Particulate Pollutants

Particulate matter pollution or particulate pollution is one of the

deadliest types of air pollution in India and on a global level. The

primary reason for the rise in particulate pollution, type of air

pollution, is because of human activities. Major sources of particulate

matter emission are factories, power stations, incinerators, industries,

automobiles, and diesel generators. All of this is anthropogenic

sources or due to human activities. So let us know more about what is

particulate matter, sources, and effects. 

What is Particulate Pollution?

Suspension of microscopic solids and liquids particles present in the

form of droplets floating in the air or atmosphere refers to as

Particulate pollution. Particulate pollution/ particulate matter/

Atmospheric particulate matter is called PM. The source of the

particle can either be natural or anthropogenic.

Particulate matter can be present in the atmosphere in the same form it

is released from the source. Sometimes PM can undergo complex

chemical reactions in the atmosphere. It is the deadliest type of air

pollution because particulate matter can easily penetrate deep into the

lungs and bloodstreams of human body unfiltered. Moreover, these

particles vary from each other in shape, size, and composition.

Browse more Topics under Environmental Chemistry

● Oxides of Sulphur and Nitrogen

● Hydrocarbons and Oxides of Carbon

● Greenhouse Effect and Global Warming

● Ozone

● Air Pollution

● Acid Rain

● Water Pollution

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Particulate matter on the basis of size can fall into two different

categories:

● Inhalable coarse particles: The diameter size of the particles

range from 2.5 to 10 micrometers (PM10 – 2.5).

● Fine Particles: Usually found in haze and smoke and the size

can range up to 2.5 micrometers (PM).

Inhalable coarse particles are present in the nearby regions of dusty

industries and roadways. Fine particles originate from forest fires.

Moreover, they can also originate on a reaction of air with gases

released from the industries, automobiles and power plants.

Size of Particulate Matter (Source: Wikipedia)

Particulate Pollutants

A particulate pollutant is a microscopic or microscopic liquid and

solid particles present in the form of the suspension in the air.

Particulate matter can be released from different types of human

activities such as vehicle emissions, smoke particles, dust particles,

and ash from industries. Particulate matter present in the air is mainly

of two types- Viable particles and non-viable particles.

● Viable Particulate Matter: These particles include lower living

organisms such as algae, bacteria, molds, fungi, etc. They are

dispersed into the air. Human beings are allergic to these

microorganisms and they can also cause different types of

diseases in plants and animals.

● Non-Viable Particulate Matter: We can classify these particles

on the basis of size and their nature. These particulates include

smoke, dust, mists, and fumes.

Video on Environmental Chemistry

Smoke Particles

Smoke particulates contain a mixture of liquid and solid particles.

Combustion of any kind of organic matter leads to the formation of

smoke particles. Examples include the release of smoke from a

cigarette, burning of garbage and dry leaves, burning of fossil fuel, oil,

etc.

Dust

The size of dust particulates is more than 1 micrometer (μm) in

diameter. Dust particulate matter originates from grinding, crushing,

and attribution of solid substances. Examples of this type of

particulate emission include the release of sawdust during word

works, release of sand particles during sandblasting, pulverization of

coal, release of fly ash and cement from factories, dust storms, etc.

Mists

Vapors in air undergo condensation to form a mist. Production of mist

is also possible by particles of spray liquids. For instance, herbicides

and pesticides are used in the form of sprays in agriculture but

sometimes it is possible to miss the spray target and enter the

atmosphere and form mists. Another example is the sulfuric acid mist.

Fumes

Formation of fumes is possible by the condensation of vapors during

different processes such as boiling, distillation, sublimation, and other

types of chemical reactions. Organic solvents, metallic oxides, and

metals undergo a chemical reaction to generate fume particles.

The adverse effect of the particulate pollutants will vary according to

the particle size. Therefore, airborne particles like fumes, dust, mist,

etc are harmful to human health. Larger particles of size more than 5

microns have the ability to enter and block the nasal passage.

However, particles of the approximate size of 10 microns can directly

enter the lungs and affect it severely.

The earlier lead was one of the major air pollutants. It causes an

interruption in the development and maturation of RBCs (Red Blood

Cells). Generation of this pollutant was possible by vehicular

emission. Lead-containing petrol or leaded petrol was one of the major

sources of air-borne lead emission in India. However, it was a thing of

the past because unleaded petrol is used nowadays. Hence, India has

gradually overcome this major air pollutant.

Effects of Particulate Matter

A particulate pollutant is very dangerous to human health, plants, and

to the entire climate. Children and elderly people are prone to diseases

caused by particulate pollution. However, normal persons can also

experience temporary problems.

Effects on Health

Exposure to particulate pollution can cause irritation of eyes, throat,

and nose. It can also cause tightness in chest, difficulty in breathing

and decrease in lung function.

Lung Cancer

PM vary in shape and size. Fine particulates can enter easily and

penetrate deep into the respiratory systems of human and can affect

the lungs. It attacks the bronchi and can cause lung cancer.

Asthma

Reports suggest that particulate pollutants can cause asthma with the

increase in the fine pollutant globally. Rising rate of diagnoses links

asthma to particulate matter pollution.

Cardiovascular Problems

Fine particles can easily enter the body without facing resistance from

the body. Therefore fine particles have a drastic impact on the heart

and the functions of the heart. Therefore, particulate matter is

responsible for many cardiovascular diseases. Frequent exposure to

PM can lead to a large amount of inhalation of particles. Therefore,

accumulation of PM will cause the buildup of plaque in the arteries

and vascular inflammation.

Atherosclerosis

Air pollutant inhalation can cause plaque buildup. This will lead to

hardening of arteries and in turn cause heart problems.

Birth Defects and Failed Pregnancy

Particles ability to enter into the body makes it easy to enter any

pregnant mothers body and then into the child during long exposure to

particulate air pollutants. Thus, the harmful chemical pollutants can

cause any type of birth defects. It is also the reason failed pregnancies

specifically in town and cities facing extreme levels of pollution.

Death

High levels of aerosols and other pollutants can cause premature

death. Air pollution due to coal industries is the cause of many

premature deaths every year in India and globally.

Effect on Vegetation and Plants

Particulate pollutants have the ability to block stomatal openings.

Therefore, it can retard the photosynthesis process. Hence, air

pollutants can damage the plant, reduce crop and vegetation yield, and

increase their mortality rate.

Effect on Climate

The rise of particulate pollution is disturbing the environmental

balance. Therefore, it is predicted that it can be the precursor of many

climatic disasters such as volcanic eruptions. Reports suggest

particulates matter can negatively impact weather on a regional level.

PM decreases the levels of evaporation of water in the Indian Ocean.

It is linked to the lack of Indian monsoon or reduction of the Indian

monsoon.

Nowadays droughts occur more often on a global scale than it used to.

Aerosol haze and particulate pollution have the ability to push tropical

rainfall and are the reason for a number of droughts human’s

experiences on a global level. PM causes the decrease in rainfall. It is

also responsible for the increase in greenhouse gases and global

warming.

Solved Question for You

Question: Inorganic or organic fine particles suspended in air refers to

as

A. Particulate Pollutant

B. Aerosol

C. Gaseous pollutant

D. Smoke

Solution: Option B

Oxides of Sulphur and Nitrogen

Do you know Delhi is one of the most polluted cities in the world?

The presence of toxic gasses and various air pollutants usually cross

the permissible limit. Central Pollution Control Board suggests that

the air quality of Delhi is in extremely poor condition and it is

breaching all the permissible air quality standards. Oxides of sulphur

and nitrogen, oxides of carbon, hydrocarbons, hydrogen sulphide,

ozone and other oxidants gaseous along with particulate pollutants like

fumes, dust, smoke, etc. are the air pollutants that are responsible for

severe air pollution in Delhi as well as many other states in India. 

Tropospheric / Air Pollution

Example of Smog in Delhi During Winter Season (Source: Delhidailynews)

The cause of tropospheric pollution is the presence of gaseous and

solid air pollutants in the air in an excess quantity than desirable. It is

primarily of two types

● Gaseous Air Pollutants– This category of air pollutants

includes substances such as oxides of sulphur and nitrogen,

hydrogen sulphide, hydrocarbons, ozone, oxides of carbon, and

other oxidants.

● Particulate Pollutants– It includes pollutants such as smoke,

dust, mist, smog, fumes, etc.

Example of Air Pollution (Source: Wikipedia)

Oxides of Sulphur and Nitrogen

We know elemental nitrogen is one of the major components of

earth’s atmosphere. Thus, it will participate in many natural processes.

It is responsible for the formation of nitrogen dioxide entering the

atmosphere. The classic example of the formation of nitrogen oxides

is by the chemical reaction of atmospheric nitrogen and oxygen during

the thunderstorm.

The chemical reaction occurs in the presence of lightning to form the

nitric oxide which further undergoes reaction with oxygen to form

nitrogen dioxide. Oxides of sulphur and nitrogen are responsible for

many natural phenomena.

Similarly, oxides of sulphur such as sulphur dioxide enter the

atmosphere by natural processes such as volcanic eruptions.

Moreover, oxidation of hydrogen and sulphide during organic matter

decomposition process in the absence of air leads to the formation of

sulphur dioxide.

Since many decades the natural processes based on oxides of sulphur

and nitrogen have been taking place and there was a global balance of

these gases in the earth’s atmosphere. However, lately many

anthropogenic or human activities led to the increase in the amounts of

the compounds more than the desired quantity.

Thus, it is causing an imbalance in the earth’s atmosphere and

exerting detrimental effects. Thus the excess quantity of the gases

makes it air pollutants. We will study the negative impact of oxides of

sulphur and nitrogen when present in excess quantity than the

permissible limit.

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Hydrocarbons and Oxides of Carbon

● Greenhouse Effect and Global Warming

● Ozone

● Air Pollution

● Acid Rain

● Water Pollution

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Oxides of Sulphur

The general term to refer to all oxides of sulphur is SOx. The major

oxides of sulphur are sulphur dioxide and sulphur trioxide. Sulphur

dioxide (SO2) gas has a characteristic pungent, irritating taste and

odour but it is a colourless gas. Moreover, it is water soluble and

forms sulphurous acid (weak acid).

Sulphur dioxide can slowly react with the oxygen present in the air to

form sulphur trioxide (SO3). However, it is not a stable compound so

it tends to react with water to form sulphuric acid. The oxidation

process of SO2 is slow without the presence of a catalyst. However,

particulate matter present in the polluted air act as the catalyst and

speeds up the sulphur dioxide reaction to form sulphur trioxide.

2SO2 (g) +O2 (g) → 2SO3 (g)

Moreover, gaseous pollutants such as hydrogen peroxide and ozone

can also promote the reaction.

SO2 (g) +O3 (g) → SO3 (g) + O2 (g)

SO2 (g) + H2O2 (l) → H2SO4 (aq)

Source of Oxides of Sulphur

The burning of sulphur-containing fossil fuel leads to the formation of

oxides of sulphur. Although sulphur dioxide is the most common gas

among oxides of sulphur it is highly poisonous to living organisms

including plants and animals.

Effects of Sulphur Oxides

Human Beings

Reports suggest even low concentrations of oxides of sulphur

especially sulphur dioxide can cause respiratory problems such as

bronchitis, asthma, and emphysema in human beings. It can also cause

eye irritation, redness, and tears.

Breathing of this air pollutant can cause irritation to nose and throat

which can further give rise to constant coughing, wheezing, breathing

difficulties and tightness in the chest. SO2 can cause bronchitis and

lung cancer on exposure to higher levels.

Plants and Vegetation

Oxides of sulphur interfere in the chlorophyll synthesis process and

damage plant cells. Moreover, interruption of chlorophyll synthesis

process will slow the photosynthesis process of the plants. Higher

concentration of sulphur dioxide stiffens flower buds. Thus, the flower

buds will eventually fall off.

It causes excessive water loss in plants. This air pollutant decreases

the quality of plant and affects plant yield. It reduces crop yields.

Oxide of sulphur is more harmful if it combines with other pollutants

such as a combination of oxides of sulphur and nitrogen, the

combination with fluorides, etc.

Materials

Sulphur dioxide causes severe erosion to stones and statues, especially

if the materials contain carbonate in them. It can also cause pitting,

scarring, and discolouration of the materials. SO2 promotes corrosion

reaction in different metals and metal surfaces in the presence of

moisture. It causes discolouration of paper, paint, fabric, leather, etc.

Acid Rain

Sulphur dioxide and sulphur trioxide present in the atmosphere

combines with water droplets during the time of rain. As a result of

which the rain falls in the form of sulphurous acid (H2SO3) or

sulphuric acid (H2SO4). This pH of this rain is much lower than the

normal pH of rainwater. This type of rain is called acid rain. The acid

rain damages soil surface, vegetation, land, etc. It causes leaching of

soil and plant canopy and loss of nutrients. Acid rain disturbs the

aquatic life.

Smog

Two primary component of Industrial smog or London smog is

sulphur dioxide and particulate pollutants such as soot, dust, smoke,

etc from burning of coal. The combustion of sulphur-containing

materials such as coal or fossil fuels releases sulphur dioxide. This

combines with water droplets and forms highly toxic particles.

However, nowadays due to the adoption of advanced measures by

industry and government, it is now a thing of past.

Oxides of Nitrogen

Nitrogen in combination with oxygen can form a series of oxides such

as nitric oxide (NO), nitrous oxide (N2O), dinitrogen tetroxide (N2O4),

dinitrogen trioxide (N2O3), and dinitrogen pentoxide(N2O5).

However, the oxides responsible for environmental pollution are NO,

NO2 and N2O.

Collectively the oxides of nitrogen are known as NOx. The oxides of

nitrogen can behave as the primary pollutant by producing toxic

reaction themselves or they can act as secondary pollutants and

combine with other pollutants to form acid rain, photochemical smog,

aerosols.

Sources

Oxides of nitrogen can form from natural as well as human activities

or anthropogenic sources. Nitrogen-containing compounds burn in

industries and automobiles to form nitrogen oxides. This is also an

example of anthropogenic sources.

The main components of air are Dioxygen and dinitrogen. They will

do react together at a normal temperature. However, during the time of

lightning the nitrogen and oxygen combine to form oxides of nitrogen

at high altitudes. When NO2 oxidizes and form nitrate (NO3) ion that

enters into the soil and acts as a fertilizer.

Dinitrogen and dioxygen combine during the burning of fossil fuel at

high temperature, released from the automobile engines, to form

significant amounts of nitrogen dioxide and nitric oxide.

N2 (g) + O2 (g) → 2NO(g) at 1483 K

The nitric oxide will rapidly react with oxygen to form NO2 (nitrogen

dioxide).

2NO (g) + O2 (g) → 2NO2 (g)

The rate of nitrogen dioxide production will increase if the reaction

occurs between stratospheric ozone and nitrogen oxide.

NO (g) + O3 (g) → NO2 (g) + O2 (g)

The irritant red haze usually seen in the traffic and congested regions

is due to the presence of oxides of nitrogen.

Effects of Oxides of Nitrogen

Human Health

It is a harmful lung irritant and can cause respiratory diseases in

children. The chemical can increase the chances of lung infections. It

is also a powerful eye irritant. The symptoms of oxides of sulphur and

nitrogen are quite similar. This can also cause coughing, wheezing,

bronchitis but few additional symptoms are colds and flu.

Elderly people and children are more prone to having asthma on

exposure for a long duration. Oxides of nitrogen can increase the

chances of acute respiratory illness such as acute bronchitis in

children. It can also increase airway resistance in adults. The gaseous

pollutant is toxic to any living tissue.

Vegetation

The gaseous pollutant can damage vegetation. It can cause damage to

plant leaves and in turn, affect photosynthesis rate. NO2 has the

potential to suppress the growth of plant even at a very low

concentration of 0.3ppm. It can make plants, vegetation, and trees

prone to diseases. Higher concentration of oxides of nitrogen can

decrease the production of chlorophyll and can cause chlorosis.

Acid Rain

Nitrogen dioxide can combine with water droplets/water vapour in the

atmosphere and fall down in the form of acid rain. Acid rain is very

harmful to materials, vegetation, soil surface, etc.

Materials

It is harmful and can cause discolouration and damage to the materials

such as fibres, textile materials, metals, etc.

Photochemical Smog

Oxides of nitrogen in the presence of sunlight and hydrocarbons can

form photochemical smog. This type of smog is very toxic and contain

a bunch of different chemical compounds such as ozone, organic

compounds (peroxo compounds, aldehydes, acetyl nitrate, ketones),

and aerosols.

Solved Examples for You

Question: Select the gaseous pollutant that causes acid rain

A. Ozone and dust

B. SO and CO

C. SO and NO

D. CO and NO

Solution: Option C.

Hydrocarbons and Oxides of Carbon

With the alarming rise of pollution levels in our environment, it is

very important that we keep ourselves informed about it. One main

thing for us to know is what exactly is contributing to this pollution.

So let us learn more about the three major pollutants- carbon

monoxide, carbon dioxide and hydrocarbons. 

Hydrocarbons

A hydrocarbon is any compound that consists carbon and hydrogen

atoms. They are organic compounds. Because of the unique covalent

nature of carbon, there are thousands upon thousands of hydrocarbons

in the world. So gasoline, petroleum, coal, kerosene, charcoal, natural

gas etc are all a form of hydrocarbons.

So as you can see hydrocarbons have widespread uses in our day to

day lives. They are also a main source of fuel for the industrial and

manufacturing sector. And in India especially, where thermal

electricity is the main source of electricity, the power sector majorly

depends on hydrocarbons such as coal.

Hydrocarbons are introduced to our environment in innumerable

ways. Be it their use as a fuel or their applications in the

manufacturing sector or even by spillage and leaks sometimes. It is

believed that 60% of air pollution is caused due to automobiles that

run on these hydrocarbon-based fuels.

Now the main culprit of this pollution is the incomplete combustion of

this hydrocarbon fuels. This causes hydrocarbons to react with

Nitrogen Oxides (NO2). When the resultant gases are hit by the sun’s

rays it leads to the formation of ozone.

Now ozone i.e. O3 is a heavy form of oxygen. It settles down in the

atmosphere. This is why polluted air (for example air near traffic

jams) feels heavy. Now ozone is a pollutant in this case and causes

smog. This incomplete combustion of hydrocarbons drastically brings

effects the air quality, causing several problems from diseases to

visibility issues.

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Oxides of Sulphur and Nitrogen

● Greenhouse Effect and Global Warming

● Ozone

● Air Pollution

● Acid Rain

● Water Pollution

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Carbon Dioxide as a Pollutant

Carbon dioxide is one of the main pollutants with regards to air

pollution. It is a primary pollutant, which means it is emitted into the

environment directly by human and natural sources. It is a greenhouse

gas, which is the main reason responsible for rising temperatures and

global warming.

Though there are many natural resources for the release of CO2, the

main being respiration by animals. this is not the cause of the excess

CO2 in the environment. The natural CO2 produced will balance out

according to the carbon cycle. The CO2 pollution is mainly attributed

to the emissions from the burning of fossil fuels.

So be it the cars that run on the road or the manufacturing plants or the

thermal electricity plants, they all release immense amounts of carbon

dioxide. Over the last hundred years or so the situation has worsened

and as of yet, there is no viable solution in sight.

Carbon Monoxide as a Pollutant

Carbon monoxide is another primary pollutant which is extremely

dangerous to the environment and also to human directly. It is

colorless, odorless and tasteless gas which is very toxic. So as you can

understand it is a potentially lethal gas.

The biggest source of CO is the incomplete combustion of

hydrocarbon fuels. When enough oxygen is not supplied during the

combustion reaction, carbon monoxide is produced.

If a location has a constant high level of CO, its environment starts to

suffer. They accumulate unhealthy levels of Ozone and Particulate

Matter (PM). This, in turn, will cause further air pollution.

Solved Questions for You

Q: The process by which carbon sinks remove carbon dioxide (CO2)

from the atmosphere is known:

a. Carbon absorber

b. Chain of Carbon

c. Carbon Sequestration

d. None of the Above

Ans: The correct answer is “C”. A carbon sink is a natural or artificial

reservoir that accumulates and stores some carbon-containing

chemical compound for an indefinite period. The process by which

carbon sinks remove carbon dioxide (CO2) from the atmosphere is

known as carbon sequestration.

Greenhouse Effect and Global Warming

The surface of the earth is heating up at a rapid pace. Till date sixteen

out of total seventeen warmest years have been recorded after the year

2000. Melting of glaciers, rising of sea levels, decrease in the forests,

danger, and scrambling of wildlife. We can trace back all the above

consequences to one common factor Global Warming. How? Let us

know! 

Global Warming

Scientist interchanges the term global warming with climate change.

Although temperature rises in certain areas but the ocean current move

the heat around in different parts of the globe. As a result of which

some regions experience cooler climate and some experience warmer

weathers. Therefore, the climate changes vary in different regions.

Hence, the term climate change is generally used by the scientists

instead of global warming.

Climatic researchers of WHO suggest global warming is the reason

for around 150,000 deaths every year globally, according to an article

published in Scientific American in 2009. Global warming is

responsible for the rise in temperature. Data from NOAA and NASA

indicates that the year 2016 was the hottest year since the inception of

climate record keeping from 1895. There has been an overall increase

of 0.8 of over the stretch of 100 years.

Earth surface has the ability to absorb almost 75% of the entire solar

energy. This is responsible for the increase in temperature. However,

part of the energy is given back to the atmosphere in the form of

radiation. There are certain gases that have the ability to trap heat and

restrict the heat from escaping from the atmosphere.

These gases are called greenhouse gases. Example of greenhouses

gases includes ozone, methane, carbon dioxide, chlorofluorocarbon

(CFC), etc. These gases absorb heat and add to the process of heating

of atmosphere thereby raising the temperature. This phenomenon is

global warming.

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Oxides of Sulphur and Nitrogen

● Hydrocarbons and Oxides of Carbon

● Ozone

● Air Pollution

● Acid Rain

● Water Pollution

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Check out our detailed article on Global Warming here.

Greenhouse Effect & Its Use

What is greenhouse effect? Was greenhouse effect always a bad

news? The answer to the second question is no. It is useful in certain

cases. There are certain places where the temperature is quite low. In

those places greenhouse room, glass surrounded room helps to grow

vegetables, fruits, and flowers. The energy from the sun enters the

room.

The room is made up of glass and it helps to retain the heat inside the

room. Therefore, the solar energy helps in warming the soil and aiding

in the plant growth and vegetation. However, the temperature of the

outside will always be lower than the temperate inside the greenhouse.

Moreover, the soil and plant release infrared radiation. Thus, the glass

reflects part of the energy and absorbs part of it.

Similarly, greenhouse effect helps in the sustenance of life and

temperature. The atmosphere of the earth has a blanket of air which

surrounds us just like the greenhouse room. The atmosphere has the

ability to restrict the heat and trap it around the earth. This

phenomenon is a natural greenhouse effect. Thus, it helps in keeping

earth warm thereby maintaining temperature and sustenance of life.

The major gas that contributes to absorption of heat is carbon dioxide.

Other greenhouse gases are methane, nitrous oxides, CFCs, and ozone.

Initially, the production of gases was within permissible quantity.

Therefore, it was useful in maintaining the natural balance and life

sustenance. However, the growing anthropogenic or human activities

are constantly increasing the gases beyond the permissible limit.

Global warming is responsible for melting of glaciers, the rise in sea

level, flooding of the coastal regions and an overall increase in the

temperature. The rise in temperature is also the reason behind increase

incidence of diseases such as yellow fever, malaria, dengue among

others. This is Greenhouse Effect.

Example of greenhouse farming (Source: Wikipedia)

Greenhouse Effect on a larger scale causes Global Warming

We all know that earth is the only planet that can support and sustain

life, rest of the planets have extremely cold or hot temperature. The

presence of the thin atmospheric layer makes it possible to support

life. The thin layer of the atmosphere contains greenhouse gases like

CO2, water vapour, methane gas, nitrous oxide, etc that has the ability

to absorb sun rays and warm up the planet.

This prevents the earth from becoming too cold. The absence of

greenhouse effect will make the Earth’s average temperature to be

nearly 60° Fahrenheit, an extremely cold planet. Hence, life would be

impossible without the greenhouse effect. However, the concentration

of greenhouse gas is on the rise since the 18th century.

At present, the carbon dioxide level is have increased almost to 40%.

The levels of greenhouse gases are at its all-time high than the

previous 650,000 years and are continuously rising. This is because

the modern life and changes in the lifestyle of humans have led to the

constant release of heat-trapping gases or greenhouse gases. This is

constantly warming up the atmosphere.

Therefore, this has started increasing the greenhouse gas to an

unnatural level and significantly increasing the greenhouse effect.

Thus, it is disturbing the environment and is altering the earth’s

temperature. This phenomenon refers to as Global Warming.

Gradual Increase in Carbon Dioxide Concentration Every Year (Source: Wikipedia)

Definition of Greenhouse Effect

It is essential to balance the incoming solar energy by radiating part of

energy back to space. We know planet Earth is much colder in

comparison to the sun. There are particular chemical compounds or

gases present in the atmosphere that allow passing of shortwave

radiation (solar energy). This will in turn heat the water bodies and

lands.

However, earth after warming up will radiate the energy at much

longer wavelengths (infrared light). Land and ocean emit this radiation

and the atmosphere along with the clouds absorbs the radiation.

Hence, the radiation will again reradiate back to the Earth due to the

presence of the greenhouse gases such as carbon dioxide, methane,

CFC, nitrous oxide, etc. This is known as greenhouse effect.

Greenhouse Effect (Source: Wikipedia)

Greenhouse Effect- A Rapidly Rising Problem

The greenhouse effect is heating up the Earth’s atmosphere.

Greenhouse gases are a rapidly rising problem because it is

responsible for climatic change at a faster rate. It is becoming difficult

for some living organisms to keep pace with this climatic change and

unable to adopt the change. This is creating new and unique

challenges to all life forms.

Therefore, the amount of the heat the greenhouse gases are trapping is

increasing with the gradual increase in the concentration of

greenhouse gases present in the atmosphere. Hence greenhouse effect

is rapidly raising the problem. Thus, we need to decrease the release

of these gases to decrease their quantity in the atmosphere.

Greenhouse Gases

Greenhouse gases include carbon dioxide, methane, and nitrous oxide.

Industrial greenhouse gases include hydrofluorocarbons, sulfur

hexafluoride, and perfluorocarbons.

Methane

The production and transport of natural gases such as coal and oil

release methane. The release of methane gas is also possible from

livestock practices, agricultural practices and decomposition of

organic waste present in the solid waste landfills.

Nitrous Oxide

Combustion of solid waste and fossil fuels releases nitrous oxide.

Moreover, industrial and agricultural activities are the cause for

release of this greenhouse gas.

Carbon Dioxide

The burning of fossil fuels such as coal, tar, and natural gas releases

CO2. Burning of waste materials, wood and trees release CO2.

Furthermore, the land use changes, deforestation, and soil degradation

are the possible causes for adding up to the already existing CO2

quantity.

Major Carbon Dioxide Emitters (Source: Wikipedia)

Fluorinated Gases

Bunch of gases including hydrofluorocarbons, sulfur hexafluoride, and

perfluorocarbons, etc are the fluorinated gases released during many

commercial and industrial activities. Sometimes the gases are released

due to household activities. However, these gases do not occur

naturally. In certain cases, these chemicals are the replacement for

ozone-depleting compounds like CFCs. However, they are equally

harmful if not more.

Global Warming and Climate Change

The major climate change due to global warming is definitely a

significant increase in global temperature. Moreover, the rise in

temperature is the reason behind many deaths. It is also the cause of

the increase in the incidence rate of some diseases such as dengue,

malaria, etc.

Global warming is a threat to animals and plants. It is disturbing the

entire ecological balance of the environment. Melting of polar ice caps

and glaciers is increasing the rise in the water levels (sea and ocean)

all around the globe. Furthermore, freshwater resources are reducing

day by day.

According to scientific organizations like NASA, WHO and such,

global warming is responsible for extreme weather incidences, ocean

acidification, and many other similar impacts that are affecting the

society and nature. However, it is possible to cease these drastic

problems by adopting proper changes to our very own lifestyle.

Regulatory bodies and the governments across the globe should

enforce proper policies to decrease the release of greenhouse gases in

the atmosphere. Government and regulatory bodies like United

Nations are actively trying to enforce policies to stop the effect.

Therefore, it is very important to participate in strong international

agreements by countries across the globe and together work to save

the planet and change the environment.

Change in Precipitation by End of 21st Century (Source: Wikimedia)

Solved Question for You

Question: The gradual reduction in the amount of the direct irradiance

on a global scale at the surface of Earth is

A. Global Warming

B. Greenhouse Effect

C. Global Dimming

D. None of the above

Solution: Option C

Ozone

All of us are aware of how the concern related to depletion of ozone

layer and the ozone hole, which also led to the ban of many chemicals

such as the chlorofluorocarbon (CFC). Depletion of O3 can increase

UV radiation entering Earth surface. This can not only lead to

different type of severe diseases like cancer but it can also threaten the

entire life on earth. Thankfully, the latest evidence suggests that the

ozone depletion has come to a halt due to global initiatives were taken

everywhere. Let us know more about this compound and its

importance.

Ozone

Have you seen the air or water purifier? One of the types of air or

water purifier utilizes ozone for removal of unwanted toxic

substances. The chemical compound can trap the bacteria and kill

them. Hence, ozone is not only present in earth’s atmosphere but it is

also possible to artificially produce this chemical substance.

Can you name another planet other than Earth that has ozone layer?

Venus has a thin ozone layer near at an altitude of 100 kilometres

from the surface of the planet. Thus, large concentrations of O3

molecules are present in the upper layer of atmosphere, specifically

troposphere.

It is a type of gaseous compound. It is made from the combination of

three oxygen atoms. Therefore, the chemical formula of this

compound is O3. The formation of O3 is a two-step reaction. In the

first step, the oxygen molecule is broken down into oxygen atoms

with the help of sunlight. In the second step, the collision of oxygen

atoms with another oxygen atom leads to the formation of ozone.

Structure of ozone (Source: Wikipedia)

We can also produce ozone artificially with the help of oxygen

molecules in the laboratory. The principle is similar to natural process.

However, voltage electric current is applied in place of sunlight.

Ozone formation takes place by placing dry oxygen in ozonizer and

passing it through high voltage electric current by silent electric

discharge. The electricity will transform the oxygen molecule into

ozone. The most commonly known ozonizers for laboratory purposes

are Siemens and Brodie ozonizer’s reaction:

3O2 + energy = 2O3

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Oxides of Sulphur and Nitrogen

● Hydrocarbons and Oxides of Carbon

● Greenhouse Effect and Global Warming

● Air Pollution

● Acid Rain

● Water Pollution

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Ozone Layer

French Physicist Charles Fabry and Henri Buisson discovered ozone

in the year 1913. Ozone layer/ shield is a region present in the

stratosphere of the earth’s atmosphere and this region absorbs majority

sun’s UV radiation. Mainly found in the lower region of stratosphere

almost 20 to 30 kilometres above Earth.

The thickness of the layer differs according to the season and

geographic region. The Earth’s stratosphere contains high

concentrations of this compound. However, it is still a small portion in

comparison to other gases present in Earth’s atmosphere. United

Nations General Assembly declared International Day for the

Preservation of the Ozone Layer on September 16th.

Importance of Ozone Shield

The stratosphere of the earth’s atmosphere contains a significant

amount of O3. Thus, this gaseous compound protects living organisms

including humans from the harmful UV radiations (λ = 255 nm).

Excessive exposure to the UV radiation for a longer period of time can

cause melanoma or skin cancer in humans.

Furthermore, it can cause many other forms of cancer and other

diseases. Overall excessive UV radiation is a threat to any living

organism. Hence, it is essential to maintain and protect the ozone

layer.

Formation of Ozone

The reaction of UV radiation with O2 or dioxygen molecules results in

the formation of O3. The UV radiation splits the oxygen molecule into

the free oxygen or O atoms. These O atoms combine with molecular

form of oxygen to form ozone (O3). It is thermodynamically an

unstable compound and has a tendency to decompose into molecular

oxygen. Therefore, a constant dynamic equilibrium is present between

the production and decomposition of O3 molecules.

O2(g) → O(g) + O(g)

(in presence of UV Radiation)

O(g) + O2(g) ↔ O3(g)

(in presence of UV Radiation)

Depletion of Ozone Layer

In the past decade, we have come across constant news about

depletion of the ozone layer. The seriousness of the situation made

global regulatory bodies like the UN and the countries to work

together to bring this constant depletion to a halt. So, what is the

reason for depletion of ozone?

The depletion of the protective O3 layer is because of the presence of

particular chemicals in the stratosphere of earth’s atmosphere. The

constant release of compounds like carbon tetrachloride, carbon

tetrafluoride, CFCs (chlorofluorocarbon) or freons and other chlorine

or bromine containing halogens in the atmosphere is the main reason

for the depletion.

CFC compounds are non-inflammable, non-toxic, nonreactive organic

molecules. Hence, it is used in air conditioners, refrigerators, plastic

foam production, cleaning computer parts, etc.

However, these chemicals mix with normal atmospheric gases and

finally reach the stratosphere. Thus, these compounds break down into

free chlorine radicals in the presence of powerful UV radiation in the

stratosphere.

CF2Cl2 (g) → Cl(g) + CF2Cl(g)

(in presence of powerful UV Radiation)

The chlorine radicals combine with the stratospheric O3 thereby

forming molecular oxygen and chlorine monoxide radicals.

Cl(g) + O3(g) → ClO(g) + O2(g)

Chlorine monoxide radicals will further react with atomic oxygen to

form more chlorine radicals.

ClO(g) + O(g) → Cl(g) + O2(g)

This process will continue and constantly regenerate chlorine radicals.

This, in turn, will lead to the breakdown of ozone. Hence, CFCs are

transporting agents that are responsible for damaging the ozone layer.

Ozone Hole

The first report of depletion in O3 layer came out in the 1980s by an

atmospheric scientist in Antarctica. This was observed over the South

Pole. Later it was found that certain specific set of conditions were

responsible for the formation of the hole. During summer season a

reaction between nitrogen dioxide and methane leads to the formation

of chlorine monoxide.

ClO(g) + NO2(g) → ClONO2(g)

Moreover, methane will also react with chlorine atoms to form

chlorine sinks.

Cl(g) + CH4(g) → CH3(g) + HCl(g)

This helps in prevention of excess ozone depletion. However, a

special type of clouds “polar stratospheric clouds” formation occurs

over Antarctica during the time of winters. These clouds provide a

surface for the reaction of chlorine nitrate. Thus, the chlorine nitrate

undergoes hydrolysis to form hypochlorous acid.

ClONO2(g) + H2O(g) → HOCl(g) + HNO3(g)

Chlorine nitrate also undergoes reaction with hydrogen chloride to

produce molecular chlorine.

ClONO2(g) + HCl(g) → Cl2(g) + HNO3(g)

However, during the springtime when the sun returns to Antarctica

again, the warmth emits sun and undergoes photolysis reaction with

HOCl and Chlorine molecule.

HOCl(g) → OH(g) + Cl(g)

(in presence of light)

The above reaction leads to the formation of chlorine and begins a

chain reaction thereby causing ozone depletion.

Cl2(g) → 2Cl(g)

(in presence of light)

Effects of Ozone Depletion

O3 depletion leads to the entry of more UV radiation into the

troposphere. UV radiations are very harmful and can cause health

issues such as skin cancer, ageing of skin, cataract, sunburn, etc. It not

only affects human health but it is also a threat to plants and other

living organisms.

Depletion in the O3 layer is responsible for killing the

phytoplankton’s, decrease the productivity of fish, etc. It can cause

mutation in plant cells by affecting the plant protein.

Furthermore, UV radiation increases the rate of evaporation from a

surface through the surface of stomata. Therefore, it decreases the

moisture content of the soil. It also affects constructions and materials.

Thus, it damages paints and fibres which lead to fading of the colour

faster.

Solved Examples for You

Question: Strangely ozone on Earth’s stratosphere serves to be a very

beneficial compound and protects us from extreme ultraviolet

radiation by absorbing most of it. However, if present in Earth’s

troposphere, the same compound act as a toxic substance. Explain

Solution: The reason for this is ozone act as a toxic gas and it is a very

strong oxidizing agent. Therefore, it can react with unburnt

hydrocarbons and form compounds like formaldehyde, acrolein, and

peroxyacetyl nitrate (PAN) thereby causing pollution. It is also one of

the major components of photochemical smog. It is also a powerful

eye irritant.

Moreover, it can cause damage to plant life. It can cause corrosion of

stones, building materials, metals and other painted surfaces. If Ozone

is present in the troposphere in excess quantity, it can cause many

diseases like a headache, nose and throat irritation, cough, breathing

problem, chest pain, and dryness of throat and so on.

Air Pollution

Air pollution is fast becoming one of the most eminent problems we

are facing. Once what was only considered a nuisance has now

become a global crisis. Everything we have learned about air pollution

can be expressed in terms of chemistry. The pollutants go through

chemical changes in the atmosphere and become toxic to the

biosphere. Let us take a look at atmospheric pollution. 

Atmospheric Pollution

We live on the Earth’s surface, in the biosphere. Just above us,

enveloping the earth is the atmosphere. The lowest region of this

atmosphere is the troposphere. It extends up to 10 km from the Earth’s

surface and then comes the stratosphere. Everything from wind

currents, cloud formation, precipitation etc happens in this two layers.

Hence most of the air pollution also occurs in these two layers of the

atmosphere. Most of the pollution that causes us so many problems

transpires in the troposphere. This is what we call atmospheric

pollution or tropospheric pollution.

We have already learned that there are various pollutants responsible

for the air pollution. In terms of environmental chemistry, these

pollutants are broadly divided into two categories – Gaseous

Pollutants and Particulate pollutants (solid pollutants). Let us see

which specific pollutants we are dealing with.

Gaseous Pollutants

1] Carbon Oxides

These are the main culprits of atmospheric pollution. They are also the

most recognized air pollutants. The major flaw of oxides of carbon is

that they are one of the main pollutants that cause the deadly

greenhouse effect on the planet.

Carbon Monoxide is a dangerous, poisonous pollutant that harms our

environment in many ways. The major source of CO is incomplete

combustion of fossil fuels like coal, wood, charcoal etc. Even exhaust

from cars contains small amounts of Carbon Monoxide.

2C + O2 → 2CO

The other carbon oxide and the most well know pollutant in the world

is Carbon Dioxide. CO2 is actually an essential element for human

survival because plants need it to perform photosynthesis. However it

is currently present in our atmosphere and our surroundings, in

extremely large quantities, and this is harmful to humans.

Carbon Dioxide is mainly released due to the burning of fossil fuels.

This is something we do for nearly everything in our day to day lives.

From manufacturing activities to running our cars to launching rockets

they all need to burn fossil fuels. This is why it is so hard to control

the emissions of CO2.

2] Sulphir Oxides

These are another class of pollutants dangerous due to the harm they

cause to living beings. Sulphur Dioxide (SO2) in particular is a nasty

pollutant that is very dangerous in high concentration. In fact, these

pollutants can cause respiratory distress and lung diseases in humans.

One major source for SO2 is the combustion of petroleum products

that contain sulphur. Sometimes even charcoal contains traces of

sulphur and releases SO2 during combustion. One natural source of

Sulphur oxides is volcanic eruptions.

This sulphur dioxide may also get oxidized and turn to SO3. And then

when reacted with moisture or water it becomes Sulphuric Acid and

precipitates on Earth as Acid Rain.

2SO2 + O2 → 2SO3

SO3 + H2O →H2SO4

3] Nitrous Oxides

Nitrogen is actually the most abundant gas in our atmosphere. It

accounts for 78% composition in air. However, oxides of nitrogen are

a major pollutant of atmospheric pollution. Just like Carbon dioxide

and monoxide, nitrous oxides are also majorly released by vehicle

emissions.

One other natural activity that produces nitrogen oxides is lightning.

When lightning strikes dioxygen and dinitrogen combine at very high

temperatures. Nitrogen Dioxide (NO2) is one of the most dangerous

pollutants there is. It has a red-brown color that one often sees over

traffic jams and in fumes coming out of factories.

N2 + O2 → 2NO

2NO + O2 →2NO2

To humans, it is particularly harmful as it directly attacks our

respiratory systems. In high concentrations, it may cause pulmonary

oedema & haemorrhage. It is toxic to plants too and slows down their

photosynthesis rate.

Particulate Pollutants

Particulate matter is the collective of all solid and liquid particles

suspended in the atmosphere which are polluting and harmful to our

biosphere. These particles originate and various different sources and

are of many sizes and compositions. This particulate matter may

originate in this form or can even be caused due to gaseous pollutants

reacting with elements and becoming particulate matter.

The size and shape of the particulate matter play a big role in how

harmful they are to the atmospheric pollution. Let us take a look at a

few of these pollutants.

● Soot: Incomplete combustion of coal and charcoal always

leaves behind a black powder-like substance. This is soot. It is

extremely small in size and toxic in nature. It can travel

through our windpipe and settle in our lungs. Soot can cause a

variety of diseases from Asthma to Bronchitis. Also, soot

contains SO2 and NO2 that form acid rain.

● Metal Particles: These oxides are formed during metal

reactions. These particles react with other compounds in the air

like SO2 and become highly toxic. If inhaled by humans they

have any ill effects on our health. One main harmful effect is

that metal particles will reduce blood’s ability to coagulate

quickly, slowing down the process

● Asbestos Dust: Asbestos is a highly toxic substance. Any

activity related to it like manufacturing asbestos sheets or

asbestos insulation can release asbestos dust. This is very

harmful and a major cause of atmospheric pollution.

● Dust Particles: Dust particles forming in everyday events or

construction or agricultural activities etc is also a pollutant.

They attach to other pollutants and become more harmful. In

humans, they may cause allergies and other respiratory

diseases.

Solved Example for You

Q: Low visibility during cold weather is due to:

a. formation of fossil fuels

b. unburnt carbon particles or hydrocarbons suspended in the air

c. lack of adequate power supply

d. none of the above

Ans: The correct answer is “B”. The suspended particles like unburnt

carbon particles and hydrocarbons mix with smoke and fog, especially

in the cold weather and the visibility is lowered. This is smog (Smog =

Smoke + Fog).

Acid Rain

We have all learned about Acid Rain before. We know that it is

caused due to a high level of pollution in the atmosphere. However,

the actual chemistry of how acid rain precipitates onto the Earth is

slightly more complicated. Let us take a detailed look at the chemistry

and causes of acid rain. 

Acid Rain

Firstly let us understand exactly what acid rain is. The pH level of

rainwater is supposed to be 5.6. While the pH value of water is 7

which is what we consider neutral, rainwater has a more acidic nature.

This is because there are some acidic compounds that are naturally

mixed in with rainwater. These compounds, such as Nitrous oxide,

carbon dioxide etc, are found in the lower levels of the atmosphere

and mix in with the rainwater.

But if the pH of rainwater falls below 5.6, it is now acidic in nature.

This is when we term as Acid rain. Acid Rain is highly toxic to all

living organisms in the world, and a major cause of land and soil

pollution.

(epa.gov)

Causes of Acid Rain

Now we are already aware that acid rain is a result of heavy air

pollution. Here we will study the two main culprits that are majorly

responsible for acid rain – Sulphur Dioxide (SO2) and Nitrous Oxide

(NOx).

Both SO2 and NO are released into the atmosphere by human

activities. These pollutants are transported into the atmosphere by

wind and air currents. Here they react with the water in the

atmosphere and oxygen in the air to form Sulphuric Acid and Nitric

Acid respectively. These acids then lower the pH value of rainwater,

making it acidic and harmful.

Let us look at the chemical reactions that occur in the atmosphere.

2SO2 (g) + O2 (g) + 2H2O (l) → 2H2SO4 (aq)

4NO2 (g) + O2 (g)+ 2H2O (l) → 4HNO3 (aq)

Now let us look at the major causes of acid rain that release these

pollutants ( SO2 and NO) into the air

● The biggest cause is electricity production by burning coal.

This thermal electricity plants are responsible for about 70% of

Sulphur Dioxide release in the world. They also release huge

quantities of NO about 20% in total.

● Any type of fossil fuels that we burn release both these

pollutants. So the burning of petrol and diesel to run

automobiles, crafts and aeroplanes is one of the major causes of

this pollution.

● Also, every production and manufacturing plant that uses

pollutants is also at fault. Especially if they do not have an

effective pollution control system in place.

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Oxides of Sulphur and Nitrogen

● Hydrocarbons and Oxides of Carbon

● Greenhouse Effect and Global Warming

● Ozone

● Air Pollution

● Water Pollution

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Forms of Acid Rain

● Wet Deposition: This is the most common form of acid rain.

The sulphuric acid and nitric acid are the main causes of acid

rain. They get mixed with the rain and fall on the earth’s

surface as acid rain. They may also precipitate in other forms

such as sleet, snow, hail, or even fog. All these are just another

form of wet acid deposition via acid rain

● Dry Deposition: Now it is not necessary that the acids mix with

the moisture and fall down as rain. They may also deposit on

the earth’s surface in a dry form. This happens more in an area

that receives an infrequent and low amount of rainfall, like

deserts and arid areas.

Dry deposition occurs when the pollutants form particles in the air.

These particles settle on the earth’s surface on land and lakes, ponds

etc. They even settle on plants and trees. Then when the rainfall

eventually occurs, the particles mix in with water and form acids.

These polluted waters then pollute the land and all living organisms in

the biosphere.

Solved Question for You

Q: Which ions among the following are present in elevated amounts in

acid rains?

a. Calcium Ions

b. Carbonate Ions

c. Hydrogen Ions

d. Hydroxide Ions

Answer: The correct answer is “C”. Acid Rain is acidic in nature.

Hydrogen ion is the characteristic ion present in an acid. Hence

hydrogen ions are present in elevated amounts in acid rain.

Water Pollution

What are the types of pollution? Water pollution is one of the major

issues India is facing at present. Untreated sewage is one of the

prominent causes of this form of pollution in India. CPCB (Central

Pollution Control Board) estimates 62 billion litres of urban sewage

flows into rivers per day. Almost 80 percent of Indian water bodies

fall among the polluted category. Imagine what will happen in the

next twenty years if proper action is not taken by each and every

citizen living in the country. So, it is very important to know more

about the causes of water pollution. 

Water Pollution and Its Types

[Source: Wikipedia]

Water is a necessary component for the sustenance of life. Even after

knowing how essential water is for the sustenance of life, we still take

water for granted and waste it time and again. Mostly, it is the human

activities that have led to water pollution and compromised with the

quality of water.

Water pollution reaches the surface or grounds via different paths. The

places of pollution or source that can be easily identified easily called

point source. In the case of the point source such as industrial and

municipal discharge pipes, the pollutant enters via these mediums in

the water source.

The identification of certain pollution sources is difficult such as

agricultural run-offs, stormwater drainage, acid rain, etc. These

sources of pollution are non-point sources. It is difficult to recognize

them because it is possible to have many agricultural runoffs like

farms, animals or crop lands from where water can enter into the water

source. Below is a list of major water pollutants and the different

sources from it originates to finally enter the water bodies.

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Oxides of Sulphur and Nitrogen

● Hydrocarbons and Oxides of Carbon

● Greenhouse Effect and Global Warming

● Ozone

● Air Pollution

● Acid Rain

● Soil Pollution

● Waste Management and Green Chemistry

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Causes of Water Pollution

Contamination of Water by Pathogens

Disease-causing agents or pathogens is one of the major water

pollutants responsible for contamination of water and causes of water

pollution. Domestic sewage and animal excreta contain different types

of pathogens such as bacteria and other microorganisms. For instance,

human excreta contain bacteria like Streptococcus faecalis and E. coli

responsible for gastrointestinal diseases.

Water Pollution Due to Organic Wastes

Another very important pollutant is organic matter like leaves, trash,

grass, dried leaves, etc. The runoff of the organic matter leads to the

pollution of water. Excessive growth of phytoplankton in water can

also be among the causes of water pollution. However, these wastes

are biodegradable (waste that can decompose).

The large bacterial population present in the water can decompose the

organic matter. These bacteria consume the oxygen present in the

water. However, the amount of oxygen present in the water depends

upon the holding capacity of the water.

The oxygen present in water is the concentration of dissolved oxygen

(DO). The DO concentration in cold water is up to 10 parts per million

or 10 ppm. This amount is very small in comparison to oxygen in the

air which is around 200,000 ppm. The DO concentration in water is a

very important factor in terms of aquatic life.

The inhibition of life can take place if the DO concentration is lower

than 6 ppm. Photosynthesis of aquatic plants releases oxygen or the

atmospheric oxygen reaching the water is the source of oxygen in any

water body. Thus, during the night there is a decrease in the

concentration of oxygen in the water because photosynthesis is not

possible and the aquatic plants constantly consume oxygen for the

respiration process.

However, if organic matter enters the water bodies, the

microorganisms present in the organic matter utilize the oxygen

available in water. Therefore, this will, in turn, cause the

oxygen-dependent aquatic life to slowly diminish and die due to lack

of oxygen in the water. Hence, anaerobic bacteria (bacteria that do not

require oxygen for their survival) will gradually start decomposing the

organic waste and produce foul-smelling chemicals harmful to human

health.

Biological Oxygen Demand

In most cases, aerobic bacteria (bacteria that do require oxygen for

their survival) utilizes the DO to decompose the organic wastes

thereby depleting the DO concentration. Therefore, a particular

amount of oxygen is needed by bacteria to decompose the organic

matter present in a particular volume of the water sample.

This is known as BOD or Biochemical Oxygen Demand. Therefore,

the amount of BOD indicates the amount of organic matter present in

a water sample. BOD indicates the amount of oxygen which can easily

break down the organic material present in a water body. The BOD

value of clean water is 5ppm. The BOD value of highly polluted water

can reach up to 17 ppm and sometimes more.

Chemical Pollutants

All of us have read that water is an excellent solvent. Therefore it can

dissolve even harmful heavy metals like mercury, cadmium, nickel,

etc. These types of heavy metals fall into the category of important

types of pollutants because they are very harmful to human body.

Moreover, human beings are not capable of excreting these heavy

metals. It will not show its effect is present in small quantity.

However, over the time the concentration of the metals will rise in the

human body due to gradual decomposition and can possibly cross the

tolerance limit.

Heavy metals if cross the tolerance limit can cause damage in different

parts of human body including kidney, liver, central nervous systems,

etc. Moreover, another type of chemical pollutants includes acids and

salts. An acid such as sulphuric acid can be found in mine drainage

and salts can be found in many sources such as sodium and calcium

chloride to melt snow and ice in colder regions.

Another set of chemical pollutants responsible for water pollution are

organic chemicals. For instance, oil spills (petroleum products) pollute

the oceans. Similarly, pesticides are a class of organic substance that

can one of the causes of water pollution when they drift down as

run-off from lands or in the form of sprays.

Additionally, industrial chemicals such as PCBs or polychlorinated

biphenyls are a class of very harmful class water pollutant. Recent

studies indicate they are carcinogenic (cancer-causing). PCB is present

in many regular household and industrial chemicals like cleansing

solvent, detergents, and fertilizers. However, nowadays biodegradable

detergents are used.

Eutrophication

The lack of oxygen can be responsible for destroying the aquatic life

of any waterbody. Chemical pollutants like fertilizer contain

phosphates in the form of additives. Therefore, phosphate addition in

water can lead to rapid growth of algae. Hence, gradually the algae

growth can cover entire water surface which can lead to the reduction

in oxygen concentration.

Therefore, lack of oxygen can cause death and decay of aquatic

animals thereby creating anaerobic conditions in the waterbody.

Hence, the water body will become bloom-infested and can inhibit the

growth of other living organisms. This entire process is

eutrophication.

Therefore, eutrophication refers to a process where water bodies

support dense plant population due to nutrient enrichment, which can

also cause animal death by depriving the animal life of oxygen thereby

resulting in gradual loss of biodiversity.

International Standards of Drinking Water

Fluoride

It is important to regularly check and maintain the fluoride ion

concentration in drinking water within the permissible limit. Lack of

fluoride in drinking water can lead to tooth decay. It is important to

add soluble fluoride in drinking water to make the concentration up to

1 ppm. However, the concentration should not cross 2 ppm or it can

lead to brown mottling of teeth. Moreover, excessive fluoride can

cause harmful effect to teeth and bones.

Lead

Lead pipes are used for water transportation and contaminate the

water in the process. The maximum permissible limit for the

concentration of lead in drinking water is 50 parts per billion. High

concentration of lead in drinking water can cause problems associated

with liver, kidney, reproductive system, etc.

Sulfates & Nitrates

Sulfate concentration greater than 500 ppm in drinking water can

cause the laxative effect. Nitrate concentration in drinking water

should not exceed 50 ppm. High nitrate concentration in drinking

water leads to harmful effects such as methemoglobinemia or blue

baby syndrome.

Other Metals

Many other types of metals can be present in drinking water.

However, the permissible limit for each metal may vary from each

other. Below table represents the permissible concentration of few

metals in drinking water.

Solved Question for You

Question: Explain the disadvantage of using biodegradable

detergents?

Solution: Even though biodegradable detergents do not contain

harmful chemicals like PCBs but there is a possibility the bacteria

responsible for decomposing biodegradable detergent can consume it

and grow rapidly. Therefore, hen these biodegradable detergents enter

the water as waste bacteria will feed and rapidly start growing thereby

using up all the oxygen present in the water. Hence, the aquatic life

will be affected.

Soil Pollution

What causes Soil Pollution? Human activities are the primary cause of

soil pollution and land degradation. By the end of this topic, you will

know how different forms of human activities are responsible for the

majority of different types of soil pollution.

Soil, Soil Pollution & Pesticides

Soil Pollution has gradually become a major challenge that we need to

overcome for establishing a healthy environment. Weathering of the

earth’s crusts by different processes leads to the formation of soil that

accumulates over the centuries. The soil is the home for a large part of

bacterial biodiversity and other microscopic and macroscopic living

organisms.

Example of Soil Pollution (Source: Wikipedia)

However, let us consider our very own country India. Indian economy

is largely dependent on agriculture. Thus, we Indians give very high

priority to the development of agriculture, fisheries, and livestock.

Therefore, for surplus production, it is very important to protect crops

from any type of damage that occurs due to insects, weeds, rodents

and other crop diseases.

So, how do we protect crops? The very obvious answer is pesticides

and herbicides. However, do you know these pesticides and herbicides

is a leading cause of soil pollution? Therefore, it is very important to

judiciously use pesticides because it contains lots of different harmful

chemicals. Therefore, to improve soil and prevent soil pollution it is

important to limit the use of pesticides and herbicides.

Causes of Soil Erosion here.

Definition of Soil Pollution

Soil pollution refers to anything that causes contamination of soil and

degrades the soil quality. It occurs when the pollutants causing the

pollution reduce the quality of the soil and convert the soil inhabitable

for microorganisms and macro organisms living in the soil.

Soil contamination or soil pollution can occur either because of human

activities or because of natural processes. However, mostly it is due to

human activities. The soil contamination can occur due to the presence

of chemicals such as pesticides, herbicides, ammonia, petroleum

hydrocarbons, lead, nitrate, mercury, naphthalene, etc in an excess

amount.

The primary cause of soil pollution is a lack of awareness in general

people. Thus, due to many different human activities such as overuse

of pesticides the soil will lose its fertility. Moreover, the presence of

excess chemicals will increase the alkalinity or acidity of soil thus

degrading the soil quality. This will in turn cause soil erosion. This

soil erosion refers to soil pollution.

Causes of Soil Pollution

Soil pollution can be natural or due to human activity. However, it

mostly boils down to the activities of the human that causes the

majority of soil pollution such as heavy industries, or pesticides in

agriculture.

Pesticides

Before World War II, the chemical nicotine chemical present in the

tobacco plants was used as the pest controlling substance in

agricultural practices. However, DDT was found to be extremely

useful for malaria control and as pest control of many insects during

World War II. Therefore, it was used for controlling many diseases.

Hence, post-war, people started using it as pest control in agriculture

for killing rodents, weeds, insects, etc and avoiding the damages due

to these pests. However, everyone gradually the adverse effects of this

chemical which led to the ban of this chemical in many parts of the

world including India.

Moreover, pests became resistance to DDT due to the chemicals

regular use. Hence this led to the introduction of other harmful

chemicals such as Aldrin and Dieldrin. Pesticides are synthetic toxic

chemicals that definitely kill different types of pests and insects

causing damage to agriculture but it has many ecological

repercussions.

They are generally insoluble in water and non-biodegradable.

Therefore, these chemicals will not gradually decompose and keep on

accumulating in the soil. Therefore, the concentration of these

chemicals will increase when the transfer of these chemicals take

place from lower to higher trophic level via the food chain. Hence, it

will cause many metabolic and physiological disorders in humans.

Chlorinated Organic toxins

The harmful effect of DDT and other chemicals led to the introduction

of less persistent organic and more-biodegradable substance such as

carbamates and organophosphates. However, these chemicals act as

harmful toxins for nerves, hence they are more dangerous to humans.

It led to pesticides related to the death of field workers in some

agricultural fields.

Learn about the Causes and Effects of Water Pollution here.

Herbicides

Slowly, the industries began production of herbicides like sodium

arsenite (Na3AsO3), sodium chlorate (NaClO3), etc. Herbicides can

decompose in a span of few months. However, even they affect the

environment and are not environmental friendly. Even though they are

not as harmful as organo-chlorides but most of the herbicides are

toxic. They are known to cause birth defects.

Furthermore, research suggests that spraying herbicides causes more

insect attack and diseases of plants in comparison to manual weeding.

One thing to note here is all the above factors occupy just a small

portion of the causes. Majority of the causes is related to

manufacturing activities in chemical and industrial processes that are

released in nature or environment.

Inorganic Fertilizers

Excessive use of inorganic nitrogen fertilizers leads to acidification of

soil and contaminate the agricultural soil. Also known as

agrochemical pollution.

Industrial Pollution

The incorrect way of chemical waste disposal from different types of

industries can cause contamination of soil. Human activities like this

have led to acidification of soil and contamination due to the disposal

of industrial waste, heavy metals, toxic chemicals, dumping oil and

fuel, etc.

Inferior Irrigation Practices

Poor irrigation methods increase the soil salinity. Moreover, excess

watering, improper maintenance of canals and irrigation channels,

lack of crop rotation and intensive farming gradually decreases the

quality of soil over time and cause degradation of land.

Solid Waste

Disposal of plastics, cans, and other solid waste falls into the category

of soil pollution. Disposal of electrical goods such as batteries causes

an adverse effect on the soil due to the presence of harmful chemicals.

For instance, lithium present in batteries can cause leaching of soil.

Urban Activities

Lack of proper waste disposal, regular constructions can cause

excessive damage to the soil due to lack of proper drainage and

surface run-off. These waste disposed of by humans contain chemical

waste from residential areas. Moreover leaking of sewerage system

can also affect soil quality and cause soil pollution by changing the

chemical composition of the soil.

After-Effects of Soil Pollution

Soil pollution is not only the problem in India but it is a global

problem. It causes harmful effect on the soil and the environment at

large. Contamination of soil will decrease the agricultural output of a

land. Major soil pollution after effects are:

Inferior Crop Quality

It can decrease the quality of the crop. Regular use of chemical

fertilizers, inorganic fertilizers, pesticides will decrease the fertility of

the soil at a rapid rate and alter the structure of the soil. This will lead

to decrease in soil quality and poor quality of crops. Over the time the

soil will become less productive due to the accumulation of toxic

chemicals in large quantity.

Harmful Effect on Human Health

It will increase the exposure to toxic and harmful chemicals thus

increasing health threats to people living nearby and on the degraded

land. Living, working or playing in the contaminated soil can lead to

respiratory diseases, skin diseases, and other diseases. Moreover, it

can cause other health problems.

Water Sources Contamination

The surface run-off after raining will carry the polluted soil and enter

into different water resource. Thus, it can cause underground water

contamination thereby causing water pollution. This water after

contamination is not fit for human as well as animal use due to the

presence of toxic chemicals.

Negative Impact on Ecosystem and Biodiversity

Soil pollution can cause an imbalance of the ecosystem of the soil.

The soil is an important habitat and is the house of different type of

microorganisms, animals, reptiles, mammals, birds, and insects. Thus,

soil pollution can negatively impact the lives of the living organisms

and can result in the gradual death of many organisms. It can cause

health threats to animals grazing in the contaminated soil or

microorganisms residing in the soil.

Therefore, human activities are responsible for the majority of the soil

pollution. We as humans buy things that are harmful and not

necessary, use agricultural chemicals (fertilizers, pesticides,

herbicides, etc.), drop waste here and there. Without being aware we

harm our own environment.

Therefore, it is very important to educate people around you the

importance of environment if they are not aware. Prevention of soil

erosion will help to cease soil pollution. Thus, it is our small steps and

activities that can help us to achieve a healthier planet for us.

Therefore, it is essential for industries, individuals and businesses to

understand the importance of soil and prevent soil pollution and stop

the devastation caused to plant and animal life.

Solved Examples for You

Question: List down some preventive measures of soil pollution?

Solution:

● Use of correct farming techniques

● Recycling of Waste before disposal

● Proper disposal method of household and industrial waste

● Use of organic fertilizers instead of chemical fertilizers and

pesticides

● Community education and awareness

● Proper maintenance of sewage system

Waste Management and Green Chemistry

Studying different types of pollution and its effect has definitely made

you realize the necessity to save the environment. So how can we save

our immediate environment? We can achieve this by controlling

environmental pollution and by the implementation of different

measures, strategies, activities, and protocols. The adoption of these

steps and strategies to control air, water, soil, and industrial waste

pollution is nothing but waste management. Let’s study more about

green chemistry in this section. 

What is Waste Management?

Waste management, also known as waste disposal, is the steps and

actions taken to manage waste from the start or release of waste to end

or final disposal. It includes the collection of waste, transport of

waste, waste treatment and waste disposal along with regulation and

monitoring of the waste disposal.

Management of waste also covers the legal and regulatory framework

related to the guidelines of waste management and recycling. Waste

can be present in the form of solid, liquid and gas. However, the steps

to dispose and management of each form is different.

Waste management and the regulatory framework encompass every

category of waste such as industrial waste, biological waste,

household waste and special types of waste. Special types of waste

include biomedical and radioactive waste materials. All the above type

of waste have the potential to harm human health but the degree of

effect may vary.

Source: Wikipedia

Waste Disposal and Management

Majority of the waste products can be traced back to human activities

for example waste disposal after extraction and processing of raw

materials in the industries. You may have seen the non-uniformity in

the waste disposal and management practices in developing and

developed countries.

Management practices also vary within a country depending upon

region (rural or urban region) and sectors (industrial or residential

sector). The sole purpose of waste management is to decrease the

impact of the adverse effect of waste on the environment, health of

living organisms, and aesthetics.

The major part of waste management is municipal solid waste

management or MSW management. The bulk of MSW consists of

industrial waste, waste from commercial activities and household

waste. However, household waste is not the only solid waste. The

waste discards originating from agricultural, medical, mining and

other industrial activities falls into the solid waste category as well.

The disposal of these wastes improperly can lead to environmental

pollution and degradation. Therefore, management of wastes and

proper disposal is very crucial to maintain the health of living

organisms and prevent environmental degradation.

Source: Wikipedia

Collection and Disposal of Waste

You might have seen small dustbins around your house and even

dustbins in particular places in your community. These are the small

initiative to keep your house and area near you clean. Hence, the

domestic waste collection is done in small bins and then it is

transferred to the larger community bins. The management,

establishment of community bins are overseen by private and

municipal employees.

Larger vehicles move around the places and collect the discards from

the community bins and discard it into the disposable site. It is the

place where the waste accumulation takes place before further

processing. Sorting of garbage on the basis of biodegradable

substances and non-biodegradable substances take place at this site.

● Non-biodegradable compounds include glass, plastic, and metal

scraps which further undergo recycling process

● Biodegradable compounds can easily be converted to compost.

Thus, they are deposited into landfills.

Browse more Topics under Environmental Chemistry

● Particulate Pollutants

● Oxides of Sulphur and Nitrogen

● Hydrocarbons and Oxides of Carbon

● Greenhouse Effect and Global Warming

● Ozone

● Air Pollution

● Acid Rain

● Water Pollution

● Soil Pollution

● Rainbow

● Stratus Clouds

● Condensation

● Parts of Plants

● Ozone Layer Depletion

● River Deltas

● Land Pollution

● Afforestation

● Leaching

● Floods and Causes of Floods

Consequences of Improper Waste Disposal

If waste does not find its way to garbage bins then it will gradually

enter the sewers. Part of the garbage will be eaten by cattle. However,

non-biodegradable waste such as metal scraps, glasses, and polythene

bags will block the sewer system and cause problem and

inconvenience.

Moreover, the consumption of polythene bags by cattle can kill the

cattle also. Thus, it is very important to practice proper waste

management protocol and discard the domestic waste in bins so the

waste will eventually be collected and disposed of. Poor waste

management can cause health problem which can further lead to

epidemics because of the contamination of groundwater.

It is extremely hazardous for people who are regularly in direct

contact with the wastes such as rag pickers and employees working for

disposing of the waste. These people handle the waste without any

types of protective devices such as gloves, masks, etc.

Green Chemistry

India was able to gain self-sufficiency in food by the end of the late

20th century with the help of pesticides and fertilizers. Moreover,

India was able to gain food self-sufficiency by implementing better

methods of farming, irrigation, high-quality seeds, etc. However,

overuse of soil and constant use of fertilizers lead to deterioration of

soil quality, water quality, and air quality.

So, how can you solve the problem? By ceasing India’s way to

development or by stopping the development process? No, definitely

not. Thus, it is essential to discover and adopt better methods that do

not control or stop the development but it helps to reduce the

environmental degradation. Here, Green Chemistry comes into play.

Let us learn more about green chemistry.

What is Green Chemistry?

Green chemistry is a whole new way of thinking or entire new

production approach that helps in using the existing knowledge and

fundamentals of chemistry and other sciences to decrease the negative

impact environment is facing. Green chemistry is different processes

and methods that can help in minimizing the effect of pollution or

environmental deterioration.

It is a combination of chemistry and chemical engineering for the

betterment of the environment. There are methods in industrial

processes that not only add to the environmental pollution but the

processes are not cost-effective and harmful to the environment. These

processes are the cause of hazardous waste generation.

Moreover, disposal of by-product generated is the cause of

environmental pollution. The process should be such that even though

the by-product cannot add anything gainful but it should not add to the

environmental pollution.

Importance of Green Chemistry

Therefore, it is important to utilize the presently available knowledge

to reduce the chemical hazards and also help in developmental

activities. This should form the basis of green chemistry. So, what are

the measures that need to be taken? For instance, we should be careful

while using certain highly toxic organic solvents like toluene,

benzene, carbon tetrachloride, etc.

We know any chemical reaction requires reactants, a medium in which

reaction will take place and proper attacking reagents. Physical

parameters such as pressure, temperature, and catalyst will decide the

extent of any reaction. Therefore, it is essential to use environmental

friendly mediums that can form environmental friendly products.

Hence, it will help in forming products without releasing any chemical

pollutants into the environment.

It is important to select starting materials during a synthesis process so

the end products yield almost 100%. This is possible by employing

optimum conditions during the synthesis process. It would be

advantageous to carry out the chemical reactions in an aqueous

medium because of properties of water. Water has low volatility and

high specific heat. Furthermore, it is non-inflammable, cost-effective,

and is devoid of carcinogenic properties.

Application of Green Chemistry in Day-to-Day Life

Dry Cleaning of Clothes

Earlier it was prevalent to use Tetrachloroethene (Cl2C=CCl2) solvent

as the dry cleaning agent. However, it is toxic and has carcinogenic

properties. Moreover, it can contaminate groundwater and can add up

to water pollution. However, nowadays liquefied carbon dioxide acts

as the detergent instead of Tetrachloroethene for dry cleaning of

clothes.

Liquid CO2 is less harmful and the extent of groundwater

contamination is less in comparison to Tetrachloroethene. Moreover,

hydrogen peroxide is also used these days for bleaching of clothes.

H2O2 provide better results and require the lesser quantity of water.

Bleaching of Paper

Earlier people were using chlorine for bleaching of paper. However,

hydrogen peroxide along with a proper catalyst produces the similar

bleaching action. Therefore, these days chlorine is replaced by

hydrogen peroxide (H2O2)

Synthesis of Chemicals

Nowadays commercial preparation of ethanal is by a one-step

oxidation process. This helps in ethanal production by ethene

oxidation in the presence of a catalyst (ionic) in an aqueous medium.

This process yields almost 90%.

CH2=CH2 + O2 → CH3CHO (90%)

Catalyst Pd(II)/Cu(II) in water

Solved Question for You

Question: Which of the option is the greenest solvent?

A. Formaldehyde

B. Ethanol

C. Water

D. Benzene

Solution: Option C.

Rainbow Colors – Meaning of Seven Colors

Everyone loves the Rainbow that forms after the rain. Rainbow is a

natural phenomenon that creates a magical effect on the environment.

Also, the rainbow colors are soothing and each color has its own

meaning.

Rainbow

Rainbow refers to an arch that is visible in the sky that is caused by

the dispersion and refraction of the sun’s light by the rain. In addition,

it can also form by water droplets present in the atmosphere.

Rainbow Colors

Every rainbow that shines in the sky consists of seven colors.

Furthermore, these colors are Red, Orange, Yellow, Green, Blue,

Indigo, and Violet. Commonly people call them VIBGYOR that is a

short form of these colors.

What is the Meaning of Seven Rainbow Colors?

Red

The first color of the rainbow is Red. Furthermore, the color has the

longest wavelength. In addition, according to Christianity, this arc

resembles Archangel Uriel that represents wisdom and energy.

Besides, Buddhism and Hinduism the red arc relates to the base or

Muladhara Chakra that is the first chakra, which connects a human

being to the physical plane.

Orange

This is the second color of the rainbow arch. Furthermore, this color is

the combination of the color before and after it (Red and Yellow

respectively). Besides, in a rainbow orange represents creativity and

the ability to enjoy oneself.

Most noteworthy, in the chakra system it represents Swadhisthana that

is energy-related with creativity, sexuality, and fertility.

Yellow

It is the third color of the rainbow arch. Furthermore, this arch relates

to archangel Jophiel that corresponds to the brilliance of thoughts and

wisdom. Besides, in the rainbow yellow represent the brilliance of the

sun.

Furthermore, in the chakra system, it represents the Manipura Chakra

that is the seat of man’s ego and personal power alike to how the sun

feeds the earth.

Green

This is the fourth color of the rainbow. Also, it relates to the

Archangel Raphael, which corresponds to healing. Besides, in the

rainbow green represents health, love, and wealth. Furthermore, in the

chakra system, it corresponds to Anahata that is the heart chakra that

has the ability to receive and give love.

Blue

It is the fifth color of the arch of the rainbow. In addition, it associates

with the Archangel Michael who is the leader of all Archangels and

also represents spirituality.

Also, within the rainbow blue denotes the spirit world and connection

with water.

Besides, in the chakra system, it represents Vishudda, which are throat

chakra and the ability to communicate with purity.

Indigo

This is the sixth color of the rainbow arch. In addition, it represents

the bridge between the subconscious and conscious worlds within the

rainbow. Furthermore, in the chakra system, it is Ajna Chakra

represented by the third eye and the capacity to see the unseen on the

spiritual level.

Violet

The last and the seventh color of the rainbow is violet. Besides, it

associates with Archangel Zadkeil who represents mercy. In addition,

within the rainbow, the color is the mixture of red and blue and it

corresponds to divine inspiration and imagination.

Furthermore, in the chakra system, it represents the Sahasrara Chakra,

which coincides with the point where human consciousness connects

with the spiritual consciousness and the divine.

Solved Question for You

Question. Which color sequence of the rainbow is correct?

A. Indigo, Violet, Blue, Green, Yellow, Orange, and Red.

B. Blue, Indigo, Green, Violet, Yellow, Orange, and Red.

C. Red, Orange, Yellow, Green, Blue, Indigo, and Violet.

D. Red, Orange, Yellow, Blue, Indigo, Violet, and Green.

Answer. The correct answer is option C.

Stratus Clouds – Definition, Facts, and Types

What is the Definition of Stratus Clouds?

There are many different forms of clouds. These forms result because

of the difference in size and height of clouds. There are the highest

clouds, mid-level clouds, and the lowest clouds. Stratus Clouds are the

lowest-level clouds.

The term status refers to a sheet or a layer. This is a term used to

denote a class of clouds that are flat and featureless capable of

producing slight drizzles. It forms a continuous grey layer covering

the sky. It can make the day feel dull and grey. The clouds when

coming very close to the ground takes the form of a fog. They are

found at a lower height as compared to altostratus, below 6000 feet.

There may be many different shapes of clouds. However, they possess

a restricted number of forms. This difference in shapes is the result of

consistent rising and falling of the clouds. They change forms within

minutes throughout the atmosphere. The formation of clouds is a

result of the condensation process. The change of liquid to gas is

known as evaporation.

Read about Layers of Atmosphere for better understanding of Stratus

Clouds

However, the vice-versa i.e. the change in state from gas to liquid is

known as condensation. On attaining saturation level i.e. a state where

the atmosphere cannot hold the water anymore is where the

condensation takes place. The water vapor condenses in a liquid or

solid form. Thus, liquid and solid forms are water or ice-crystals

respectively. Let us have a look at facts and types of stratus clouds.

Facts & Types In Relation to Stratus Clouds

It is a cloud with a horizontally layered appearance. Furthermore, the

rising air in the lower heights of the Earth’s atmosphere leads to the

formation of such types of clouds. There are also many subforms of

stratus clouds. These include:

Altostratus clouds: Altostratus clouds are middle layered clouds. The

sun is visible through these clouds. There is a possibility of rain In

thickened clouds. However, this form is changed to nimbostratus

when the possibility of rain becomes persistent.

Cirrostratus clouds: Cirrostratus clouds are high level, thin clouds that

are difficult in the detection and can create halos. The level of

moisture is huge in the upper troposphere. Thus, cirrostratus clouds

are formed. These types of clouds are common in the polar regions of

the lower stratosphere.

Stratocumulus clouds: These are clouds resembling a much of

cumulus clouds. However, the exception is that it is largely dark, and

also the clouds are grouped together i.e. in larger masses. The chances

of precipitation are almost nil. However, there may be slight rain

sometimes. These types of clouds are a sign of coming of storms,

characterized by gusty winds and dull weather. Moreover, they are

viewed underneath the cirrostratus and altostratus.

Nimbostratus clouds: Nimbo refers to precipitation. Thus,

nimbostratus clouds are rain layered clouds. There is no occurrence of

lightning or thunder. They lead to ceaseless rain, but no thunder. Thus,

they are dark and gray in appearance.

Stratus clouds thus form a blanket that tends to cover the entire sky.

These are in combination with other types. Also, there are many

species of such types of clouds. The subforms of stratus clouds

provide knowledge of the effects of the same on the weather, thus

helping to forecast the situation.

Questions on Stratus Clouds

Q. Formation of stratus clouds near the ground is known as:

1. Smoke

2. Fog

3. Smog

4. Vapors

Ans: The correct answer is 2.

The stratus clouds, when formed near the ground, is known as fog.

The falling ambient temperature of the air or the added moisture in the

air causes fog.

Condensation – Meaning, Process, and Examples

What is Condensation?

Its summertime and you’re thirsty. You take out a bottle of chilled

water and keep it aside after drinking. After that, you notice small

beads of water on the bottle later. It is quite fascinating to watch. But,

where did it come from? Similarly, imagine that you are taking a hot

shower. Once you’re done, you take a look at the mirror. The fog

covers the mirror and you can’ see anything. Once you wipe it off, you

see the same small water beads. This is exactly what condensation is.

Meaning of Condensation

Condensation refers to the process of water vapour changing into

liquid water. In other words, the water present in the air i.e. water

vapour cooled down when it came in contact with your mirror’s

surface after the hot shower. This resulted in the vapour condensing or

turning into a liquid form. Thereon, you will notice moisture or water

beads plus fog which was in the mirror.

Therefore, condensation is a change in the state of water from a gas in

a liquid form. It takes place when the vapour in the warm air meets a

cool surface. However, it does not necessarily require a solid surface.

To simplify it, just think of condensation as the opposite of

evaporation.

Process of Condensation

Just like any other matter, water also consists of molecules. The

molecules are energetic, fast-moving and far apart when they are in

the form of vapour. Thus, when this vapor bumps into cooler

temperatures, they become the opposite. That is, they get slower,

lesser energetic and drift closer. Subsequently, the vapour turns into

liquid upon reaching a threshold energy level.

Anyone can demonstrate the process of condensation through an easy

experiment. You will require a cup and water. Fill a cup nearly

two-thirds full of hot water. Take one more cup, flip it upside down,

and put it on top of the cup with hot water. Then put an ice cube on

top of the upside-down cup.

Condensation will start to form at the top of the upside-down cup, just

like a cloud. Therefore, you can try out this experiment at home with

kids to make them understand this phenomenon in a better and

effective manner.

Examples of Condensation

Condensation happens at both large scale and small scale. It is an

everyday event that takes place right in front of our eyes. You are

surrounded by this phenomenon if you think of it. Some common

examples of this occurrence are –

Morning Dew – This happens when the moisture present in the air

condenses on the grasses and leaves cooling overnight.

Droplets on can or bottle – The cold surface of your can or bottle

causes the moisture in the warm air to condense on its surface.

Foggy windshield – The air in your car has moisture. Moreover, the

breath and bodies of the inhabitants of the car add to it. When there is

enough moisture and the windshield is cool, the moisture condenses

on the windshield as droplets.

Foggy breath – Cold weathers allow your inner moisture to condense

into large droplets. It is also a prime example of condensation

happening without any surface to collect drops on.

Foggy mirror – As we discussed earlier. You mirror fogs up after a hot

shower. It happens because the shower moisture condenses on the cool

mirror.

Clouds – Another example of condensation without surface clouds.

Questions on Condensation

Question- What is the Opposite of Condensation?

A. Precipitation

B. Evaporation

C. Sublimation

D. Deposition

Answer- The correct answer is B. It is the opposite of evaporation.

Parts of Plants and Their Functions

Plants are an important part of human life and vegetation as well.

They are very beneficial to us and give us a lot of things. We are

surrounded by plants, but have you ever stopped to notice the parts of

a plant? All parts of plants are important and carry out different

functions. All of them come together to perform their respective

functions for the healthy life of the plant. We will dig deep into the

parts of plants and their functions.

Parts of Plants

A plant is made up of primarily four parts. They are –

● Roots

● Stem

● Leaf

● Flower

Functions of Parts of Plants

Function of Roots

A plant has roots that grow in the ground. This underground part plays

a very important role in pulling the water and minerals so they can

reach the plant. Furthermore, it also expands within the ground so that

for better water absorption the water increases.

Roots also play the role of anchors which helps in creating better

stability. In addition, the roots also fuse the development of the plant

and stock reserve food material. They also store food that binds the

soil together.

Function of Stem

The stem is the part that stays above the ground. A stem usually bears

leaves, fruits plus flowers. It distributes the nutrients and minerals all

the way from the plant to the leaves. Furthermore, the stem is the

support system of the plant.

Moreover, it shields the plant and assists in asexual dissemination.

The thorns of a stem protect it from animals as well. The growth of a

stem takes place upwards allowing leaves to reach the sunlight for

photosynthesis.

Function of Leaf

It is safe to say that a leaf is one of the most important parts of a plant.

It contains chlorophyll which assists the plants in preparation for food.

Moreover, the veins of a leaf allow the flowing of nutrients plus water.

A leaf has three basic parts which are petiole, leaf base and lamina.

The leaves of the plant help in photosynthesis. Moreover, they help in

removing any excess water via stomata. In short, it is for transpiration.

Moreover, some plants have leaves which also assist in the process of

reproduction. Thus, leaves perform a number of functions, which

helps the plant grow healthier.

Function of Flower

The bright and beautiful part of the plant which you see is the flower.

They play a role in making food. A flower has female as well as male

parts. Both of these work collectively to fertilize the plant so it can

produce seeds.

A flower consists of four basic parts, which are petals, sepals,

stamens, and pistil. The petals attract insects and birds in order to

pollinate them. After that, the flower buds are protected by sepals.

Similarly, the stamens which are the male part and the pistil that is the

female part help in the reproduction system.

Questions on Parts of Plants

Question- Which of the following is the female part of the flower?

A. Petals

B. Sepals

C. Stamens

D. Pistil

Answer– The correct answer is option D. The pistil is the female part

of the plant It holds the structure that becomes the fruits and seeds. It

consists of three functional parts which are stigma, style, and ovary. It

helps in the reproductive system as when stamens or birds or bees

drop pollen onto the pistil, it pulls in the pollen. Then it begins to yield

a fruit that will develop and help diffuse the seed of the plant.

What is Ozone Layer Depletion?

Ozone layer depletion means the thinning of the ozone layer present in

the upper atmosphere. That is harmful to nature and the atmosphere.

Ozone layer depletion is one of the major problems for the atmosphere

and also for all the living beings including the flora and fauna of this

earth.

What is the Ozone Layer?

The ozone layer is the layer present in the Stratosphere. It absorbs the

harmful ultraviolet rays that come from the sun. Moreover, it causes

harmful radiation that has a high concentration of ozone (O3) which is

harmful to living beings on the earth.

The ozone layer is basically present in the lower stratosphere that is

near about 20 to 35 kilometers above the earth. Moreover, the

thickness of the ozone layer may differ depending upon the seasonal

and geographical changes.

The ozone layer is important for the earth because it protects the earth

from the harmful ultraviolet radiation. This radiation comes from the

sun and is harmful to the earth’s surface

The flora and the fauna would not be able to survive if the earth will

be directly affected by the harmful ultraviolet rays. Moreover, humans

and animals on earth will face a lot of problems because of excess

heating.

Causes of Ozone Layer Depletion

According to the studies done by the scientists the cause of the ozone

layer depletion is human activity. All the activities are done by human

beings. Through which the chemicals are made that contain chlorine

or bromine. These are basically called ODS that stands for

Ozone-Depleting Substance.

The ozone layer depletion was observed by the researchers in the early

1970s. Furthermore, the ozone-depleting substances are said to be

Eco-friendly and they are very popular for the last some decades and

are still in use.

These ozone depletion substances float and then reach the

stratosphere. Therefore, the formation of chlorine and bromine takes

place and these chemicals cause the depletion of the ozone layer at a

very high speed.

They are capable of breaking down the molecules of the ozone layer.

One chlorine molecule has a capacity to breakdown thousands of

molecules present in the ozone layer, therefore, it results in the

depletion of the ozone layer.

Natural Causes of Depletion of the Ozone Layer

It is found that the ozone layer gets affected by some natural causes

that are sun-spots and stratospheric winds. However, these cause a

very nominal contribution to the ozone layer depletion which is near

about 1 to 2 percent and therefore these effects are temporary. Some

major volcanic eruptions have also contributed to the depletion of the

ozone layer. Two of them are (Chichon in 1983) and another one is

(Mt. Pinatubo in 1991).

Man-made Causes of Depletion of the Ozone Layer

Human activities are the main cause of the depletion of the ozone

layer. It occurs due to the excessive use of the man-made chemicals

that are bromine and chlorine which release from the man-made

compounds such as:

● Chlorofluorocarbons (CFCs)

● CFCs (chlorofluorocarbons)

● Halon

● CH3CCl3 (Methyl chloroform)

● CCl4 (Carbon tetrachloride)

● H CFCs (hydro-chlorofluorocarbons)

● Chlorofluorocarbons

● Methyl bromide

Solutions to Ozone Layer Depletion

Less use of Fuel: by reducing the usage of the fuels and petroleum

used in vehicles nowadays we can help in reducing the ozone layer

depletion

Less use of pesticides: pesticides helps in growing your farms and

plants but cause harm to the ozone layer and contribute to ozone layer

depletion.

Limited use of harmful chemicals for cleaning: the chemicals used for

making cleaning products results in depletion of the ozone layer.

Questions on Ozone Layer Depletion

Ques. Ozone Layer consists of:

(A). O3

(B). H2O

(C). Na Cl

(D). H2sO4

Ans. The answer is option A.

River Deltas – Introduction, Formation, Types

The submission of sediments by a river near its mouth point before it

drains into a body of water leads to the formation of river deltas. A

river delta forms at the mouth of a river where the river deposits the

sediment load which it carries. Moreover, it drains it into a

slower-moving or static body of water.

Introduction to River Deltas

Formation of a River Delta usually occurs when the river joins a sea,

estuary, ocean, lake, reservoir or in rare cases a slower moving river.

The deltas of rivers are usually highly fertile areas and thus some of

the most densely populated settlements of humans are based on such

deltas. Major examples of major deltas of the world are the Nile River

delta and the Ganges River delta.

Formation of River Deltas

There are various criterions which constitute the formation of a river

delta. Under this segment of the article, we will discuss some of those

points:

1. The river needs to carry sufficient sediment to deposit at its

mouth to form the delta.

2. The tidal currents or waves of the river need to be weak. It is

because the river is unable to carry the sediments into the body

of water which it joins.

3. The river must drain into a body of water that is either static or

has a slow flow rate to prevent the fast removal of sediments

carried by the river at its mouth.

When a river enters its last phase before it drains into another body of

water, it is usually no longer confined to the channel in which it flows

but its waters spread out as it enters another body of water. The

spreading out of the river decreases its velocity and this, in turn,

reduces its capacity to carry the great load of sediments with it. Hence,

the sediments get deposited on the river bed and river banks. As the

sediments build up over time, the river no longer flows through a

single channel since the heavy deposits of sediments impede the flow

of water.

Types of River Deltas

1. Wave-dominated deltas

In wave-dominated deltas, wave-driven sediment controls the shape of

the delta. Waves also cause deltas to retract and reflect by eradicating

sediments from the river’s mouth.

2. Tide dominated deltas

A tide controls the shape of the delta in the case of tide-dominated

deltas. Erosion plays a significant role in shaping such deltas.

Distributaries are formed in such deltas when there is sufficient water

in the region like during storm surges and floods. These distributaries

gradually silt up and finally become non-existent. The Ganges river

delta is a great and famous example of the tide-dominated delta.

Solved Question For River Deltas

Question: Write a short note on Gilbert Deltas

Answer: A Gilbert delta is formed when the sediments deposited to

form the delta are coarse in nature. While some suggest that Gilbert

deltas are formed at both marine and lacustrine locations, others

suggest that they are formed when the river waters blend more easily

with the waters of a freshwater lake. Moreover, usually in cases of

rivers entering the sea or a salt lake, the waters of the river float.

Land Pollution – Definition, Causes, and Prevention

The world is getting polluted day by day as you read this. Human

activities have given birth to different kinds of pollution that are

harming our planet. One of those kinds is land pollution. We are all

aware that land pollution is equally distressing and destructive.

Therefore, we must find out the causes and solutions to this pollution.

Definition of Land Pollution

Land Pollution refers to the deterioration of the earth’s land surfaces.

Furthermore, it occurs mainly due to the indirect and direct effects of

human activities. Similarly, when we misuse the land resources, land

pollution happens.

It is a global issue that needs to be fixed immediately. The

unnecessary materials contaminate the quality of our land. For

instance, even the garbage on the streets is a kind of land pollution

only.

Causes of Land Pollution

There are various causes which contribute to this pollution. The

various substances that spill on the land cause land pollution.

Similarly, these substances have different sources of origin. The most

common ones are:

● Garbage

● Factories

● Farming

● Mining

Garbage

This is one of the most common causes of land pollution. You will

find garbage in every household. Tonnes of garbage is produced by

common households annually. When such massive amount gets

generated, the ways to dispose of it falls short.

Therefore, all this garbage gets dumped onto land. This land of

disposal is referred to as a landfill. It is basically a wastage of free

land which also gives birth to new problems. For instance, these

landfills release toxic gases that harm living beings as well as the

ozone layer.

Factories

Factories contribute largely to land pollution. They produce toxic

waste products and chemical which prove very damaging to land.

Furthermore, these factories dump off their waste in lands and water

bodies. While some countries have stringent laws against this, some

do not. This increases land pollution.

Farming

We know farming is very important for every person. They fulfill our

food demands. However, irresponsible farming becomes very harmful

sometimes.

Clearing of forests for land area in order to farm makes way for land

pollution. Moreover, the insecticides and fertilizers sprayed on crops

also damage the land.

Mining

It is yet another activity that contributes to land pollution. In order to

obtain coal and minerals, we dig holes into the land. This results in

land erosion.

Similarly, it also produces harmful gases and toxins which results in

contaminated land as well as the air.

Prevention of Land Pollution

There are many ways which can be taken on a bigger level as well as a

small one. It can help in preventing land pollution. In order to execute

it, the government and citizens must come together to do so. We can

begin with:

Reducing the usage of chemicals and pesticides

Reducing the use of chemical fertilizers and pesticides can help in

preventing land pollution. In addition to contaminating the soil, they

also do no good to the crops.

Therefore, farmers must use natural ingredients instead of these

harmful toxins. They can switch to manure and bio-fertilizers. This

will help in minimizing land pollution.

Reforestation

As we know that forests and grassland bind the soil. We must practice

reforestation to protect the land from pollution. It will further prevent

floods and soil erosion. Moreover, it will make the land more fertile

and enhance biodiversity.

Recovering and Recycling Material

We must recycle waste material to stop it from polluting the land. We

must properly dispose of organic and inorganic waste separately. It

will help in lessening the burden of landfills. Moreover, it will save

more natural resources.

Solved Question for You

Question- Which of the following does not contribute to land

pollution?

A. Mining

B. Farming

C. Reforestation

D. Garbage

Answer– The correct answer is ‘C’.

Afforestation – Definition, Advantages, and Disadvantages

We know that our earth is turning into a concrete jungle with the onset

of industries and commercialization. Furthermore, this time of crisis

has resulted in various ways of harming the environment. We need to

help our earth heal so there can be a better future. One way is to

practice afforestation. It is an environment-friendly practice which is

quite beneficial. However, you might be unaware that it has

disadvantages too. We will find out how.

Definition of Afforestation

Afforestation is a method to establish a forest. It is a great way of

making those lands greener which has been without forests for quite a

time or none at all. It has a lot of benefits which can help both

mankind and the environment.

In other words, it can have a positive impact on the environment and

also reduce levels of carbon dioxide. However, if we do not practice it

correctly, it will harm the species diversity and agriculture profits.

Advantages of Afforestation

The afforestation of afforestation outweighs its disadvantages.

Nonetheless, we must practice is effective to not face the

disadvantages.

Forest Rebuilding

When we cut down trees of a forest, we cause way too much damage

to everything it comprises of. This cutting down happens for various

reasons. We need wood, build homes and also for agricultural

practices. All this results in loss of habitat, change in climate as well

as the loss of biological diversity.

When we restore these areas, we allow these forests to naturally

replenish over the course of time. One may also require planting only

the native trees which once grew there. Similarly, it will also reverse

the biodiversity losses which happened due to deforestation. It will

also help in cleaning the atmosphere and restoring it to its former

condition.

Creating New Forests

When we practice afforestation in areas that had no forests, it gives us

benefits of its own. Moreover, this conversion of semiarid lands into

forests makes them more sustainable and prevents soil erosion too.

Moreover, we can also create sustainable infrastructure in addition to

reducing the levels of carbon dioxide in our environment. Through

this practice, we can add to the forest density of the world.

Flood Control

One of the greatest benefits of afforestation is definitely flood control.

Through this method, we can enhance the water filtration. In addition,

we can also control floods by planting more trees. Moreover,

excessive sediment transport can be prevented too.

In other words, forests reduce the impact of flooding. It is able to do

so because it delays and reduces the size of the floods. Furthermore, it

scatters the water in a more steady way.

Disadvantages of Afforestation

While there are many advantages of afforestation, we also have

various disadvantages. This practice needs to be managed properly. If

we do not pay careful attention, we may lose our local biodiversity.

Moreover, it will also modify certain biomes. Additionally, when we

will introduce non-native and invasive species it can damage

biodiversity. It also reduces the streamflow and various people lose

their income from agriculture.

Similarly, the native grasslands which we convert to forests might not

have a similar habitat for local species. Thus, it will result in a lack of

plant diversity which will, in turn, decrease the number of accessible

habitat types for forest dwellers.

Solved Question for You

Question- Which of the following is an advantage of afforestation?

A. Loss of local biodiversity

B. Reduced streamflow

C. Flood control

D. Economic loss

Answer– The correct answer is option C. Afforestation helps in

controlling the floods.

Leaching – Definition, Process, and Questions

Whenever we brew a cup of tea or make an instant coffee, leaching in

action is visible. Leaching is basically a process of extracting any

substance from a solid material that has to come in contact with a

liquid element. However, leaching the liquid is much important. The

liquid facilitates the ability to remove or extract any given substance

from a solid matrix i.e. material.

Definition of Leaching

Leaching is a primary process in hydrometallurgy, in this, the metal

values of a solid metal bearing elements are transferable into an

aqueous solution by the action of a lixiviant. Within the industry of the

chemicals, the process of leaching is usually referred to as the

extraction process. When we make a hot cup of green tea we need a

green tea bag and some hot water for making it.

Moreover, we proceed with boiling it and then add it to a cup. As we

steep our green tea bag inside the hot water, what we notice? Notably,

the water here not only just changes in color but it also extracts the

green tea from the tea bag into the water. After steeping it for a couple

of minutes, we sip it and not just taste the hot water but also the taste

of the green tea leaves through it.

Although preparing tea is a very common process. This process of

making tea is also an ideal example of working of the leaching. We

take a solid matrix like a tea bag then we introduce it to a liquid.

During this process, the hot water extracts the components from the

tea bag and the water gets a flavor. Now that we know what actually

leaching is, let’s look at this process in more detail.

Process of Leaching

Firstly, the solvent comes in contact with the solid matrix. A solvent is

usually a liquid substance that functions for dissolving a substance or

the solute. A solute is an element that a solvent dissolves. Thus, the

solvent will become the liquid and the solute would be the substance

we would extract from the solid matrix. Moreover, referring to our

example of the tea, the solute would be our green tea extracted

whereas the hot water would be the solvent.

Above all, the solvent moves through the solid matrix, separating the

substance, or solute, from this matrix so that we can collect it. This

step of the process is usually known as percolation. Percolation is just

a fancy word we generally use for filtering. We essentially filter out,

or separate, the solute that we desire from the solid matrix, with the

use of a solvent.

Shrinking-Core Model

As we know, while leaching a solid with a liquid the solid goes to the

liquid phase while the earlier one remains. The removal of the solid as

liquid dissolves into a particle that leads to a diameter of a

non-leached core that shrinks with the time.

Eco-Friendly Leaching

We are able to see if organic acids are eligible for the use of leaching

of lithium and cobalt from the batteries with a little success.

Experiments that we perform with varying temperatures and the

concentrations of metal acid shows that the optimal situations are 2.0

m/L of the organic acid at a temperature of near about 90 °C. The

reaction has overall efficiency exceeding 90% with no other harmful

byproducts.

4 LiCoO2(solid) + 12 C4H6O5(liquid) → 4 LiC4H5O5(liquid) + 4

Co(C4H6O5)2(liquid) + 6 H2O(liquid) + O2(gas)

Questions on Leaching

Ques. The boiling point of any solvent is:

(A). Boiling solvent.

(B). Decoction.

(C). Leaching.

(D). None of the mentioned.

Ans. (B). Decoction.

Floods – Definition and Different Causes of Floods

Flood is a term used to denote an enormous amount of water. When

there is an outflow of water in a place, it is said to be flooded. The

situation caused when the water becomes uncontrollable is said to be

flooded. The flood may take different forms such as in the form of

heavy rainfall when there is a breaking of the dam. Furthermore, the

melting of snow also leads to flooding. Floods lead to an overfull and

huge spread of water but are not considered safe for the purpose of

drinking. Thus floods bring with them a number of diseases such as

typhoid, cholera and many others. Here, we shall discuss the various

causes of floods.

Causes of Floods

Flood is usually a result of natural causes. It may also be caused by

man-made factors. It causes huge damage to life and property. There

are many different causes leading to flooding. Some prominent among

them include:

Massive Rainfall

Drainage systems and the effective infrastructure design aid during

heavy rains. They help the drainage of excess water into reservoirs in

an easy way. But in cases of heavy rainfall, the systems stop working.

Thus flood is caused.

Overflowing of the Rivers

The people living along the river always have a risk of life from the

overflowing of the Rivers. To prevent such a situation, a string of

dams are built. However, if these dams are not managed properly, they

may cause flooding and huge damage.

Collapsed Dams

In the event of huge rainfall, the dams built begin to collapse. Thus,

causing the flood situation to become even critical for the people

living around.

Snowmelt

At the time of the high melting of snow due to heavy precipitation and

other factors, the situation of flooding arises. Adopting sustainable

measures for heavy precipitation can help in dealing with the flooding

situation.

Deforestation

The cutting of trees in a reckless manner i.e. deforestation is also a

major cause of man-made flooding. Trees prevent soil erosion and

also the loss of crops. The vegetation is also enriched as a result of

more and more trees. This also blocks the massive flow of rain, thus

preventing flooding.

Climate change

The climatic changes caused due to human practices also add to the

risk of flooding. Human beings cut trees in a large number, thus

affecting the process of photosynthesis. Thus increased level of

carbon-di-oxide in the atmosphere cause changes in climate posing

threats of natural disasters like floods etc.

Emission of Greenhouse Gases

The burning of fossil fuels, the industrial influences, the pollution all

is depleting the level of the ozone layer and increasing the level of

greenhouse gases, becoming a major cause of man-made flooding.

Other Factors

The broken supply lines cause the outflow of water but lead to less

damage. Also, there is water flow from the washing machines.

Furthermore, overflow from dishwashers worsens the situation. Also,

the lack of proper sewage systems adds to the destruction of this

natural disaster.

Thus, a flood can be caused both due to natural causes as well as it can

be a human-made flood.

Flood causes a huge loss of life and property. Waterborne diseases

spread as a result of Floods causing health problems. Moreover, the

destruction of roadways and infrastructure facilities, the disturbance of

ecosystems, improper sewage systems all demand serious efforts of

adopting sustainable measures.

Taking steps such as afforestation, decreased the emission of harmful

gases into the atmosphere could help. Also, enrichment of vegetation,

fewer deeds causing pollution and treatment of sewage could be useful

ways to combat the situation.

Solved Question for You

Q. Risk of flooding can be reduced by:

1. The building of dams, detention basins

2. Educational and awareness programs related to floods.

3. Building regulations for new developments.

4. All of the above

Correct Answer: Correct Answer is 4.

The risk of flooding can be reduced by taking all the necessary actions

stated above.