Chapter 12: Air

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Section 1: What Causes Air Pollution? Objectives

1. Name five primary air pollutants, and give sources for each. 2. Name the two major sources of air pollution in urban areas. 3. Describe the way in which smog forms. 4. Explain the way in which a thermal inversion traps air pollution.

A. Primary and Secondary Pollutants

1. Primary Air Pollutants • Put directly into the air by human or natural activity • Table 1, p. 304

Pollutant Description Primary Sources Effects 1. Is an odorless,

colorless, poisonous gas that is produced by the incomplete burning of fossil fuels

Cars, trucks, buses, small engines, and some industrial processes

Interferes with the blood’s ability to carry oxygen, slowing reflexes and causing drowsiness, and can cause death in high concentrations

2. When combustion (burning) temperatures exceed 538oC, nitrogen and oxygen combine to form nitrogen oxides.

Burning fuels in vehicles, power plants, and industrial boilers

Can make the body vulnerable to respiratory infections, lung diseases, and cancer; contributes to the brown haze seen over cities and to acid precipitation

3. Sulfur dioxide (SO2)

Contributes to acid precipitation; can react to form secondary pollutants, which can harm plant life and irritate the respiratory systems of humans

4. Volatile organic compounds (VOCs)

Burning fuels... vehicles are major source

Contribute to smog formation; can cause serious health problems, such as cancer; and may also harm plants

5. Particulate matter (particulates or PM)

Most come from construction, agriculture, forestry, and fires, but may also come from vehicles and industrial processes

Can form clouds that reduce visibility and cause a variety of respiratory problems; have been linked to cancer; may also corrode metals and erode buildings and sculptures

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2. Secondary Air Pollutants • Form when a primary pollutant comes into contact with other primary pollutants – or

with a naturally occurring compound like water vapor – and a chemical reaction occurs

• Example: ____________________, which forms when VOCs react with atmospheric oxygen in the presence of ultraviolet rays

B. The History of Air Pollution

• Has occurred since the discovery of fire • Is worse today due to the combustion of fossil fuels in industry and motor vehicles

C. Motor Vehicle Emissions ______________________________________________________

1. Controlling Vehicle Emissions ______________________________________________________ • Gave the EPA authority to regulate vehicle emissions in the US • Required the gradual elimination of lead in gasoline (lead content has been reduced

by >90% since 1970) • Required _________________________ to be placed on cars to clean

exhaust

2. California Zero-Emission Vehicle Program • Established in 1990… By 2016, 16% of all vehicles sold in CA must be ZEVs • ZEVs: have no tailpipe emissions, no emissions from gasoline, and no emission-

control systems that deteriorate over time • Other states with ZEV programs: Maine, Massachusetts, New York, and Vermont

D. Industrial Air Pollution ______________________________________________________

______________________________________________________

1. Regulating Air Pollution from Industry Clean Air Act (1970): • Required industries to use scrubbers or electrostatic precipitators to clean air before

releasing it o ____________________: machines that move gases through a spray of

water o ______________________________: machines used to remove dust

particles and ash from smokestacks (p. 307) 2. ____________________ ( = smoke + fog)

• ___________________________________________________ • Results from chemical reactions involving sunlight, air, automobile exhaust, and

ozone

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3. Temperature Inversions • Generally, air circulation in the atmosphere keeps air pollution from reaching

dangerous levels. • ___________________________________________________.

Usually, as it rises, it carries pollutants into the upper atmosphere. • A temperature inversion occurs when rising warm air is trapped by a layer of cool air,

which is trying to fall. The warm air, which is less dense, cannot continue to rise and take the pollution away.

Section 2: Air, Noise, and Light Pollution Objectives

1. Describe three possible short-term effects and long-term effects of air pollution on human health.

2. Explain what causes indoor air pollution and how it can be prevented. 3. Describe three human health problems caused by noise pollution. 4. Describe solutions to energy waste caused by light pollution.

A. Effects of Air Pollution on Health Very young or elderly people, as well as those with heart or lung problems, are

particularly susceptible to the effects of air pollution.

1. Short-term Effects • Are reversible if exposure decreases • Examples: headaches; nausea; eye, nose, and throat irritation; respiratory problems,

including bronchitis and pneumonia

2. Long-term Effects • Long-term exposure may damage the lungs of young people or worsen pre-existing

medical conditions in older people • Examples: emphysema, lung cancer, and heart disease

B. Indoor Air Pollution • May be worse than the outside air pollution • Major sources: Fig. 9, p. 311

1. Radon Gas • ___________________________________________________ • Is produced by the radioactive decay of ___________________, which occurs

naturally in the Earth • Can seep through cracks and holes in foundations, where it adheres to dust particles…

When people inhale the dust, they inhale radon, which can damage lungs (2nd leading cause of lung cancer in US)

2. Asbestos • ___________________________________________________

___________________________________________________

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• Was commonly used as an insulator and fire retardant prior to the 1970s, when the US banned most asbestos products

• If inhaled, it can cut and scar the lungs, causing ____________________… victims experience increased difficulty in breathing and ultimately, victims may die of heart failure

C. Noise Pollution

• _______________: a sound of any kind, measured in _________________ (dB; Table 2, p. 312)

• Noise pollution: unnecessary noise that affects human health and the quality of human life

D. Light Pollution

• Does not directly affect human health but does negatively affect the environment by causing (1) A diminished view of night sky (2) ___________________________________________________

• Solutions: shielding and directing light, using timers, and/or using energy-efficient light sources

Section 3: Acid Precipitation Objectives

1. Explain the causes of acid precipitation. 2. Explain how acid precipitation affects plants, soils, and aquatic ecosystems. 3. Describe three ways that acid precipitation affects humans. 4. Describe ways that countries are working together to solve the problem of acid

precipitation. A. What Causes Acid Precipitation?

• Acid precipitation: acidic rain, sleet, or snow that is produced by the burning of fossil fuels, which releases SOX and NOX and causes the following reactions: (1) ___________________________________________________ (2) ___________________________________________________

• pH scale: Fig. 12, p. 314 • ____________________: a drop in the pH of soil and surface water due to acid

precipitation… can harm ecosystems • ____________________: a rapid change in water pH

B. How Acid Precipitation Affects Soil, Plants, and Aquatic Ecosystems

• Acidification changes soil chemistry by (1) ___________________________________________________

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(2) ___________________________________________________ (3) ___________________________________________________

Which can harm or kill plants and aquatic organisms. • Acid shock can kill entire aquatic populations • Solution? Neutralize acidic water using powdered limestone (CaCO3), which is basic

C. Acid Precipitation and Humans

Acid precipitation may lead to • ______________________________________________________

______________________________________________________ • Increased respiratory problems in children • Jeopardized jobs (i.e., farmer, fisher, forester) • Destroyed buildings

D. International Conflict and Cooperation

• Air pollutants may be released in one area but fall downwind 100s of kilometers away (Fig. 16, p. 317)

• ____________________________________ (1991): agreement between U.S. and Canada to reduce acidic emissions that flow across their boundary