8.3 + 8.4

Ch. 8.3: Environmental and Health Effects

Ch. 8.4: Air Pollution Control

5/2/23, Ms. Havu

Environmental Science

Take notes on anything bolded or italicized

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8.3 Environmental and Health

Effects

Consequences of breathing dirty air include:
increased probability of heart attacks, respiratory
diseases, and lung cancer.

This can mean as much as a five to ten-year decrease
in life expectancy if you live in a large city.

How does air pollution cause these health effects?
Pollutants can irritate and damage delicate tissues in
the eyes and lungs and cause scarring, and even
tumor growth. They can stress the heart and even
bind to hemoglobin, reducing oxygen flow to the
brain.

Multiple Choice

Where do you have the highest chance of breathing dirty air and decreasing your lifespan?

• Maine

• Philadelphia, PA

• Cherry Hill, NJ

• Antarctica

Multiple Choice

Why do you have the largest chance of breathing dirty air there?

• Because there are a lot of factories

• Because there are a lot of cars

• Because there are a lot of people smoking

• All of the above

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Acid Deposition Results

From SO4 and NOx

Deposition of acidic droplets or particles, from rain,
fog, snow, or aerosols in the atmosphere, became
recognized as a widespread pollution in the 1980s.

Acidic deposition is now understood to affect forests
and croplands far from industrial centers. Rain is
normally slightly acidic (pH 5.6). Industrial emissions
of sulfur dioxide (SO2), sulfate (SO4), and nitrogen
oxides (NOx) can acidify rain, fog, snow, and mist to
pH 4 or lower. Ongoing exposure to acid fog, snow,
mist, and dew cause permanent damage to plants,
lake ecosystems, and buildings.

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Forest Damage by Acid Rain

© William P. Cunningham

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Acid Precipitation Over the

United States

Multiple Choice

When is rain considered acidic?

• When its pH is 5.6.

• When its pH is below 4.

• When its pH is above 4.

• When its pH is above 5.6.

Multiple Choice

What is the reason for the change in the graphs of acid precipitation over the US?

• 2013 had less rain than 1986

• 2013 had more forests than 1986

• Control of sulfur dioxide emissions was better in 2013 than 1986

• There was a huge fire in 1986

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Buildings and Monuments

Show Clear Damage

Air pollution is destroying
some of the oldest and
most glorious buildings and
works of art.

Smoke and soot coat
buildings, paintings, and
textiles.

Acids dissolve limestone
and marble, destroying
features and structures of
historic buildings.

© Ryan McGinnis/Alamy

Multiple Choice

What most likely caused the damage to this statue?

• Dust and soot covered it

• Someone punched it in the face

• Acid rain dissolved it

• The artist just made it that way

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Urban Areas Endure

Temperature Inversions

In urban areas, pollution is most extreme when
temperature inversions develop, concentrating
dangerous levels of pollutants.

A temperature inversion is a situation in which
stable, cold air rests near the ground, with warm
layers above. This situation reverses the normal
conditions.

Los Angeles has ideal conditions for inversions.

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Temperature Inversions Can Trap

Air Pollution over Cities

Multiple Choice

Where and when are you most likely to experience temperature inversion?

• Maine, at night

• LA, at night

• LA, during the day

• Antarctica, during the day

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Heat Islands and Dust Domes

With their low albedo, concrete and brick surfaces in
cities absorb large amounts of solar energy.

As a result, temperatures in cities are frequently

warmer than in the

surrounding countryside, a condition known as an
urban heat island.
Tall buildings create convective updrafts that sweep
pollutants into the air. Stable air masses created by
this heat island over the city concentrate pollutants
in a dust dome.

Multiple Choice

Why is Philadelphia typically warmer than the surrounding suburbs?

• We have a high albedo because of all the trees

• We have low albedo which absorbs more sunlight

• We are in between two rivers

• We are further east

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Poor Visibility Over Los Angeles

© Jacobs Stock Photography/BananaStock/PunchStock RF

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Smog and Haze Reduce Visibility

Pollution affects rural areas as well as cities.

Grand Canyon National Park, where maximum
visibility used to be 300 kilometers (185 miles), is
now so smoggy on some days that visibility is only 20
kilometers (12.5 miles) across the canyon.

Huge regions are affected by pollution. A gigantic
“haze blob” as much as 3,000 kilometers (about
2,000 miles) across covers much of the eastern U.S.
in the summer, cutting visibility as much as 80
percent.

Open Ended

What was the main idea of 8.3?

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8.4 Air Pollution Control

“Dilution is the solution to pollution:” this catch
phrase has long characterized our main approach to
air pollution control.

Tall smokestacks were built to send emissions far
from the source, where they became difficult to
detect or trace to their source.

With increasing global industrialization, though,
dilution is no longer an effective strategy. We have
needed to find different strategies for pollution
control

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The Best Strategy is Reducing

Production

The best strategy is reducing pollution, but pollutants can
also be captured from effluent after burning.

• Particulate removal involves filtering air emissions.

Filters trap particulates in a mesh, or electrostatic
precipitators are used.

• Sulfur removal is important because sulfur oxides are

among the most damaging of all air pollutants in terms
of human health.

• Nitrogen oxides (NOx) can be reduced in both internal

combustion engines and industrial boilers.

• Hydrocarbon controls mainly involve complete

combustion or the control of evaporation.

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Electrostatic Precipitator Can Remove

99% of Unburned Particulates

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Clean Air Legislation is Controversial

But Extremely Successful

The Clean Air Act of 1963 was the first national
legislation in the United States aimed at air pollution
control.

In 1970, an extensive set of amendments essentially
rewrote the Clean Air Act.

The 1990 amendments included major changes in
incentives as well as rules for additional pollutants.

The 1990 amendments also provided incentives and
rules to support development of alternative fuels and
technology.

Multiple Choice

The Clean Air Act was first amended, and essentially rewritten, in:

• 1963

• 1970

• 1990

• 2000

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Trading Pollution Credits is

One Approach

A cap-and-trade approach sets maximum emission
levels for pollutants.

Facilities can then buy and sell emission “credits,” or
permitted allotments of pollutants.

Companies can decide if it’s cheaper to install
pollution control equipment or to simply buy
someone else’s credits.

Cap-and-trade has worked well for sulfur dioxide.

Open Ended

What was the main idea of 8.4?