Chapter 1 – Earth’s Changing Atmosphere

Section 1.4 – Human activities affect the atmosphere

Objectives

• BEFORE, you learned

• More about how radiation and gases affect each other

• About the ozone layer and ultraviolet radiation

• About the greenhouse effect

• NOW, you will learn

• What the types and effects of pollution are

• About the effect of human activities on greenhouse gases

• How the ozone layer is changing

– Air pollution – smoke and other harmful materials that are added to the air. Some you can see/smell and there are some that you cannot see/smell at all but do exist!

– Air pollution moves around by wind (outdoors) or fans (indoor)

I. Human activity can cause air pollution

A. Types of Pollution

1. Gas pollutants – some of these gases occur naturally in the

atmosphere and are only considered pollutants when they are likely to cause harm

a. Examples: includes carbon monoxide, methane, ozone, sulfur oxides, and nitrogen oxides

• 2. Particulates – are tiny particles or droplets that are mixed in

with the air that interfere with our breathing, sunlight, and air quality

a. Examples: smoke, dust, dirt, pollen, tiny bits of salt from the oceans,

II. The ozone layer protects life from harmful radiation Examples of pollution: Human Activities: Smog – combination of smoke and fog; unburned fuels

Fossil fuels – gases and particles

Manufacturing – gases and particles

Tractors/construction equipment – dust and soil

Farming – fertilizers and pesticides

III. The greenhouse effect keeps Earth warm. Natural Sources:

Dust, pollen, soil, salt

Volcanoes and forest fires

B. Effects of Pollution

a. Effects on people

i. Irritate your eyes, nose, throat, and lungs

ii.Can smell bad and make it hard to breathe

iii. Can develop lung diseases and other health problems

iv.Can cause extra problems for those suffering from asthma

b. Other Effects

i. Can stick to surfaces and damage plants, buildings, and other objects outdoors

ii.Dusty air or a dust storm can darken a day and make it difficult to see

iii.Can be carried high into the atmosphere where it can be reflected or absorbed sunlight and affect the weather

iv.Can be moved from the air to ground, lakes, and oceans harming those things

C. Controlling Pollution 1. Smog/Ozone alerts

In some cities, smog becomes so bad that its dangerous for people to exercise outdoors

Some cities will ask people not to drive when the weather is likely to produce smog

2. Government/Laws

Clean Air Act – limits the amounts of air pollution that factories and power plants are allowed to release. Also sets rules to make car exhausts cleaner

Environmental Protection Agency (EPA) – measures air pollution and works to enforce the laws passed by Congress

II. Human activities are increasing greenhouse gases A. Sources of greenhouse gases

1. Plant growth, forest fires, volcanoes, and other natural processes affect the amounts of carbon dioxide and other greenhouse gases in the atmosphere.

2. The amount of greenhouse gases then affects temperatures on Earth

3. The higher temperatures affects plant growth and other processes that produce or reduce greenhouse gases

4. Human activities are producing greenhouse gases faster than natural processes can remove the gases from the air.

Natural Sources

• dust, pollen, soil, salt • volcanoes and forest fires: gases and particles

Human Activities

• fossil fuels: gases and particles • unburned fuels: smog • manufacturing: gases and particles • tractors/construction equipment: dust and soil • farming: fertilizers and pesticides

B. Global Warming

• The air contains 30% more carbon dioxide than it did in 1700’s.

• Temperatures have risen in recent decades.

• Scientists predict that temps will increase 2.5-10.4 degrees F by 2100.

• Global warming can affect – sources of food, the amount of water and other resources available, and even human health

C. Reducing Greenhouse Gases

Kyoto Protocol - would require developed nations to release no more greenhouse gases each year than they did in 1990

The US has not accepted it

1990, over 1/3 of all greenhouse gases released were from the US

Technology can also help reduce global warming

Examples – develop new ways to cool/heat buildings, transport people/goods, make products that use less energy, producing energy without using fossil fuels

III. Human activities produce chemicals that destroy the ozone layer

• About 85% of chlorine comes from human activity

• Excess chlorine starts a chemical reaction and breaks down the ozone layer prohibiting it to create a new layer either to balance the loss

• Montreal Protocol – a plan to stop making and using chemicals that harm the ozone layer

Since 1987, 180 nations have signed the agreement

If countries continue to follow the agreement, ozone levels will return to normal in about 50 years