CHE 468-UNIT 1

CHE 468

UNIT 1: Lecture 1 & 2

Environmental Engineering Technology

Dr. Benjamin Afotey [email protected] // 0249312880

UNIT 1:

INTRODUCTION TO ENVIRONMENTAL POLLUTION & ENGINEERING

• What is Environmental Engineering? Entails designing new methods of production and new methods of

pollution control in order to protect the environment from human development.

• Definitions and Types of Pollutants Pollution is a synonym for contamination. Therefore, pollutants are

things that contaminate the air, water and land in some manner. Any solid, liquid or gas that is present in the environment (air, water, land) in concentrations that causes some deleterious effect is considered a pollutant.

Air pollution is the presence in the outdoor atmosphere of any one or

more substances or pollutants in quantities which are or may be harmful to human health or welfare, animal or plant life or property or unreasonably interfere with the enjoyment of life or property, including outdoor recreation.

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INTRODUCTION TO ENVIRONMENTAL POLLUTION &

ENGINEERING • National Ambient Air Quality Standards (NAAQS) have been established

for six criteria air pollutants:

five primary (meaning emitted directly from the source)

particulate matter (PM), sulfur dioxide(SO2), nitrogen dioxide(NO2), Carbon monoxide (CO), and particulate lead(Pb)

one secondary pollutant (because it is formed in the lower atmosphere by chemical reactions among primary pollutants). ozone (O3).

Another class of compounds – Volatile Organic Compounds (VOC)- though not a criteria pollutant, is recognized as a major primary pollutant because of its large emissions and its importance in the reactions that form the ground level ozone.

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INTRODUCTION TO ENVIRONMENTAL POLLUTION &

ENGINEERING

• Overview of Pollution Issues

• Smog and Acid Precipitation

• Ozone Depletion

• Global Warming

• End-of-Pipe Treatment and Pollution Prevention

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Environmental Legislative and Regulations

• A number of legislative efforts to control the introduction of pollutants into the environment include: Clean Air Act ,CAA

Air Pollution Control Act, APCA

Motor Vehicle Air pollution Control Act, MVAPCA

National Environmental Policy Act, NEPA

Clean Air Act Amendment, CAAA

Clean Water Act, CWA

National Pollution Discharge Elimination System, NPDES

Safe Drinking Water Act, SDWA

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Environmental Legislative and Regulations

• The Environmental Protection Agency, EPA required by the CAAA of 1970 to establish NAAQS;

both primary standards (to protect public health)

and stricter secondary standards (to protect public welfare).

• The CAAA of 1970 also required the various states to submit State Implementation Plans (SIP) for attaining and maintaining the national primary standards.

• Tough standards were also to be written by EPA for certain new industrial plants, such as the power plants, and were to be implemented and enforced.

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Environmental Legislative and Regulations:

NAAQS

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Environmental Legislative and Regulations: Selected Examples of New Source Performance Standards (NSPS)

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National Emissions Standard for Hazardous Air Pollutants (NESHAPs)

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Causes, Sources and Effects of Major Pollutants

• A cause: is fundamental, that is, a cause explains why or how a pollutant is formed.

• A source: is locational; that is a source identifies what type of process, industry, or device discharges a particular pollutant.

• Focus is mainly on control of stationary sources, not that pollution from vehicular source is less important

• Air pollution problem from mobile sources is growing more severe each year. In various countries around the world, motor vehicles account for some 10-60% of

total air pollution emissions. design of vehicle pollution control equipment is a specialized field and is limited

essentially to the vehicle manufacturing companies.

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• Particulate Matter, PM: is very-small diameter solids or liquids that remain suspended in exhaust gases and

can be discharged into the atmosphere. They are caused by one of the three fundamental processes.

Material-handling, such as crushing or grinding ores or loading dry materials in bulk can result in the creation of fine dusts.

Combustion processes can emit small particles of noncombustible ash or incomplete burned soot.

Particles can also be formed by gas conversion reactions in the atmosphere between certain pollutant gases that were emitted previously.

• Major sources of particles include industrial processes, coal and oil burning electric power plants, residential fuel combustion and highway vehicles.

• Particulate effects include reductions in visibility such as smog or haze, soiling of buildings and other materials, corrosive and erosive damage of materials and alteration of local weather. Also particulates can damage human and animal health and retard plant growth.

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China’s Air Pollution Problem

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• Sulfur oxides (SOx) are caused by burning sulfur or any material containing sulfur.

• The main source is fossil-fuel combustion for electric power generation, although certain industrial processes such as petroleum refining and nonferrous metal smelting can be important sources in specific locations

• SO2 and SO3 can form acids when they hydrolyze with water, and the acids can then have detrimental effects on the environment. In addition, SO2 has been associated with human health problems, damage to plants and animals, smog and haze through the formation of acid mists, and corrosion of materials.

• At concentrations above 1 ppm, some bronchoconstriction occurs; above 10 ppm, eye, nose, and throat irritation is observed. SO2 also stimulates mucus secretion, a characteristic of chronic bronchitis (Goldsmith 1968).

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• Nitrogen oxides (NOx) are formed whenever any fuel is burned in air. At high temperature, N2 and O2 in the air combined to form NO and NO2.

• Organically bound nitrogen atoms present in some fuels can contribute substantially to NOx emissions. Total U.S. emissions of NOx are almost equally distributed between mobile sources and stationary combustion sources.

• Nitrogen oxides contribute to smog, are injurious to plants and animals, and can affect human health. NOx contributes to acidic deposition. Furthermore, NOx reacts with reactive VOCs in the presence of sunlight to form photochemical oxidants.

• The effects of NO2 on people include nose and eye irritation, pulmonary edema (swelling), bronchitis, and pneumonia. Long-term exposure to NO2 concentrations below this range can contribute to pulmonary fibrosis and emphysema (Stokinger and Coffin 1968).

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Causes, Sources and Effects of Major Pollutants • Photochemical Oxidants and VOCs

• Photochemical oxidants are caused by complex network of chemical reactions that occur in the ambient atmosphere. These reactions involve VOCs and NOx and are initiated by absorbing ultraviolet energy from sunlight. One of the main product of this reaction is ozone, which is a very reactive oxidizing gas.

• VOCs and NOx are both emitted in large quantities by motor vehicles and because of the importance of sunlight, photochemical oxidants are usually more prevalent in large, sunny urban areas with heavy traffic.

• Other major sources of VOCs are industrial processes like petrochemical processing, surface coating, printing, and other large operations involving organic solvents.

• Ozone and other oxidants are severe eye, nose, and throat irritants; eye irritation occurs at 100 ppb, and severe coughing occurs at 2.0 ppm. Although the NAAQS for ozone is based on a J-hour maximum, Lippmann (1989) points out that reductions in lung functions can occur in as little as five minutes of exposure to concentrations in the range of 20 to 150 ppb. Furthermore, these acute (short-term) effects worsen as the dose (concentration x exposure time) increases.

• Lippmann (1989) also raises the concern of chronic (long-term) effects. For example, people exposed to seasonally elevated concentrations of ozone for years may experience irreversible, accelerated lung aging.

• Other effects of oxidants include severe cracking of synthetic rubber and deterioration of textiles, paints, and other materials. Oxidants cause extensive damage to plants, including leaf discoloration and cell collapse (Brandt and Heck 1968), with effects starting at concentrations as low as 50 ppb.

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Trends in U.S annual emission rates for SOx, PM, VOCs and NOx

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Causes, Sources and Effects of Major Pollutants • Carbon monoxide (CO) is caused by the incomplete combustion of any carbonaceous

fuel. Power plants and other large furnaces are usually designed and operated carefully enough to ensure nearly complete combustion and do not emit much CO.

• The major source is the transportation sector. However, residential heating accounts for a significant fraction of total national CO emissions as do certain industrial processes.

• Carbon monoxide can have significant effects on human health. CO reacts with the hemoglobin in blood to prevent oxygen transfer. Depending on the concentration of CO and the time of exposure, effects on humans range from slight headaches to nausea to death.

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lyrespective O and CO of pressures partialP P where

P

P

HbO

HbCO

2OCO

O

CO

2

2

,

2102

lyrespective O and CO of pressures partialP P where

P

P

HbO

HbCO

2OCO

O

CO

2

2

,

2102

Trends in U.S annual emission rates for CO and Lead

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• EXAMPLE 1-1 • Estimate the percentage of HbCO in the blood of a traffic officer exposed to

40ppm CO for several hours. Assume the HbCO content reaches 60% of its equilibrium saturation value.

• SOLUTION 1-1 • Air is approximately 20.9% oxygen, so at saturation

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%3.20234.0

0024.0

024.004.060.0

04.01000000209.0

40210

2

2

actual

2

HbCO percent and HbCO

1.HbCO

HbCO

1.0HbOHbCO

: blood the in HbCO of Fraction

HbO

HbCO

n saturatio60% At

HbO

HbCO

Research Studies of the effects of air pollutants on human health

• Sample PM Health Studies: Increased Mortality A review of 57 studies in 37 cities worldwide found a causal relationship

between fine particle exposure and cardiopulmonary mortality (Journal of the Air & Waste Management Association, 2001)

A 16-year study by Harvard University researchers found that fine particulate pollution can shorten life spans by 2 years.

In this study of 8111 residents of 6 US cities, particulate pollution was strongly associated with excess deaths from lung cancer and heart disease, even when other lifestyle risks such as cigarette smoking were factored out.

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• Sample PM Health Studies: Heart Attacks, Bronchitis, Asthma, Cancer A study of 772 heart patients, conducted by the Beth Israel Deaconess

Medical Center in Boston, found that the risk of heart attack rose 40% on days when particulate levels were higher (reported 2001). By comparison, the increased risk from smoking is 500%.

A Loma Linda University study of 6340 Seventh Day Adventists living throughout California found that residents living in areas which exceeded federal standards for particulate matter on 42 or more days per year had: a 33% greater bronchitis risk

a 74% greater asthma risk

a 37% higher risk of developing some form of cancer (women)

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• Sample Carbon Monoxide Health Studies: Heart Birth Defects Researchers at UCLA reported that the risk of heart birth defects

was 2-3 times greater when levels of carbon monoxide or ozone were high during the second month of pregnancy - when the heart forms. (American Journal of Epidemiology)

The study included more than 9300 babies born between 1987

and 1993 in 4 Los Angeles area counties. The study matched heart birth defects with air-pollution data

gathered by 30 monitoring stations.

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• Sample Ozone Health Studies: Increased Asthma Attacks Researchers from NYU and Norwalk Hospital in Connecticut found that children

with asthma were 40% more likely to suffer asthma attacks on days with high ozone levels (reported by the American Lung Association, 1997)

Children attending summer asthma camp were studied for 3 years

On the highest pollution day, when ozone levels reached 160 ppb averaged over one hour, children with asthma were 40% more likely to suffer increased symptoms compared to days with average ozone levels of 84 ppb.

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• Sample Ozone Health Studies: Increased Asthma Onset A 2002 study in the medical journal Lancet links ozone smog to

increases in asthma cases. 3535 children in Southern California were tracked for 5 years.

Children who played 3 or more outdoor sports in smoggy areas were more than 3 times as likely to develop asthma.

Scientists had long thought that air pollution only worsens asthma - this study found that it can also contribute to onset of asthma.


• Sample Ozone Health Studies: Increased ER Visits A study of 25 hospitals in Montreal, Canada, found that in summer

1993, an increase in maximum ozone levels of 36 parts per billion (ppb) averaged over one hour was associated with a 21% increase over the average number of daily ER visits for people ages 64 and older (reported by the American Lung Association in February 1997)

A study conducted by Harvard School of Public Health found that

ozone exposure was linked with up to 15,000 hospital admissions and 50,000 emergency room visits for respiratory conditions in 13 US cities during 1993-94 (reported by the American Lung Association, 1996).

On average, up to 10% of asthma admissions during the ozone season

were attributed to elevated ozone levels.

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• The Global Picture Air pollution in the developing world is responsible for at least 50

million cases of chronic cough in children under age 14.

Respiratory disease is now the leading cause of death in children worldwide. (Air & Waste Management Association Environmental Manager, February 2000)

“At least 220 million people in cities of the developing world lack clean drinking water, 420 million do not have access to the simplest latrines, 600 million do not have adequate shelter, and 1.1 billion choke on unhealthy levels of air pollution.”

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Thank You

For any concerns, please contact

[email protected],

[email protected] // 0322 191132

CHE 468-UNIT 1

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