Announcements – Oct 25

Test results are in.

CNNBooming China's acid rain 'out of control' November 30, 2004 China's explosive economic growth is outpacing environmental protection efforts, leaving the country awash in "out of control" acid rain. Acid rain fell on more than 250 cities nationwide and caused direct annual economic losses of $13.3 billion, equal to nearly three percent of the country's gross domestic product. Two major causes were the rapidly growing number of cars and increasing consumption of cheap, abundant coal as the country struggles to cope with energy shortages and meet power demand. China is the world's largest source of soot and sulphur dioxide (SO2) emissions from coal, which fires three-quarters of the country's power plants.

Third of China 'hit by acid rain' Sunday, 27 August 2006

One third of China is suffering from acid rain caused by rapid industrial growth, an official report quoted by the state media says.

Pollution levels have risen and air quality has deteriorated, the report found. This comes despite a pledge by the authorities to clean up the air.

CNN, November 16, 2004 Study links smog increase, urban deathsCHICAGO, Illinois (Reuters) -- Increases in air pollution caused by cars, power plants and industry can be directly linked to higher death rates in U.S. cities. Reducing such ozone pollution by about 35 percent on any given day could save about 4,000 lives a year across the country. The conclusion came from a look at 95 urban areas where about 40 percent of the U.S. population lives, comparing spikes in ozone pollution there with death rates from 1987 to 2000. Ground-level ozone typically increases when temperatures rise. While short-term increases have been recognized as causing jumps in hospital admissions, this study provides strong evidence of short-term effects of ozone on mortality," said Francesca Dominici, an author of the study.

Air Quality I

Lecture Objectives:

1) What are the major types and sources of airborne pollutants?

2) What are the issues with ozone?

3) Has the Clean Air Act been effective?

Atmosphere Atmosphere - air above the earth 78% nitrogen, 21% oxygen, 1% carbon

dioxide, water, other gases

AtmosphereDivided into four zones: Troposphere, Stratosphere, Mesosphere, Thermosphere

Decrease in density further from EarthTroposphere is where weather takes placeStratosphere contains most of the ozone

Atmosphere Airborne particles mix, dilute, but remain in

atmosphere

Accumulate in direction of winds

Can lead to health problems

Asthma Adults with

asthma: 14 million (6.9%) (2001)

Children with asthma: 6.3 million (8.7%) (2001)

Number of deaths: 4,269 (2001)

http://www.cdc.gov/nceh/airpollution/about.htm

Air pollutants Primary air pollutants

Materials that when released pose health risks in their unmodified forms

Secondary air pollutantsPrimary pollutants interact with one another,

sunlight, or natural gases to produce new, harmful compounds

Primary Air Pollutants Five major materials released directly into

the atmosphere in unmodified forms. Carbon monoxide Hydrocarbons Particulate matter (2.5 m and 10 m) Sulfur dioxide Nitrogen oxides

189 substances are regulated under the Clean Air Act

Carbon Monoxide (CO) Produced by burning of organic material

(coal, gas, wood, trash, etc.)

Automobiles biggest source (80%) Decreases because of fuel efficiency, catalytic

converters Offset by increase in number of cars, time spent

driving

Cigarette smoke another major source

Carbon Monoxide (CO) Toxic because binds to

hemoglobin, reduces oxygen in blood

Not a persistent pollutant, combines with oxygen to form CO2

Most communities now meet EPA standards, but rush hour traffic can produce high CO levels

Hydrocarbons (HC) Hydrocarbons - organic compounds with hydrogen,

carbon

From incomplete burning or evaporated from fuel supplies

Major source is automobiles, but some from industry

Contribute to smog

Improvements in engine design have helped reduce

Particulates Particulates - small pieces of

solid materials and liquid droplets (2.5 m and 10 m)

Examples: ash from fires, asbestos from brakes and insulation, dust

Easily noticed: e.g. smokestacks More attention, more regulation

Particulates Can accumulate in lungs and interfere with the ability

of lungs to exchange gases.

Some particulates are known carcinogens

Those working in dusty conditions at highest risk (e.g., miners)

pollution decreased 88% from 1970 - 2000

Sulfur Dioxide (SO2) Produced by burning sulfur

containing fossil fuels (coal, oil)

Coal-burning power plants major source

Reacts in atmosphere to produce acids

One of the major components of acid rain

Sulfur Dioxide (SO2) When inhaled, can be very corrosive to lung

tissue

London 1306 banned burning of sea coal 1952 “killer fog”: 4,000 people died in 4 weeks

tied to sulfur compounds in smog

Nitrogen Oxides (NO, NO2) Produced from burning of

fossil fuels

Contributes to acid rain, smog

Automobile engine main source

New engine technology has helped reduce, but many more cars

Acid Rain Sulfur dioxides and Nitrogen oxides combine with

water in the atmosphere to form sulfuric acid and nitric acid

The pollutants remain airborne for ~1-3 days and travel 250-750 miles

Combine with water in the atmosphere, fall back as rain, snow, etc. – water with pH more acidic than normal rainfall.

US and Canadian governments officially recognized effects in 1986

Effects of Acid Rain Can degrade buildings and monuments

made of limestone

Effects of Acid Rain Can acidify freshwater lakes (pH<4.7)

Disrupt physiological processes Release of toxic compounds normally bound to

soil (e.g. aluminum) Inhibition of nitrification, build up of ammonia Causes loss of game fish & other desirable

species 25,000 lakes in N. America altered by

acidification Midwest lakes often on limestone, which

neutralizes acids

Photochemical Smog Photochemical smog – secondary pollutants

formed by reaction of nitrogen oxides and HC with sunlight

Includes ozone (O3) destroys chlorophyll, injures lung tissue ground-level ozone is “bad ozone”

Photochemical Smog Biggest problems in

cities, mountains can make it even worse

Mountain ranges, wind directions lead to thermal inversions

when cool air is trapped below layer of warm air

pollutants accumulate, aren’t released to upper atmosphere

http://www.epa.gov/airnow/ozone.html

Hazardous Air Pollutants Hazardous Air Pollutants (HAP) are

compounds that can harm human health or damage the environment.

Some released from consumer activities. Benzene escapes during automobile refilling.

Most released from manufacturing Toxic chemicals released from smelters Chemical and petroleum industry are primary

sources

Indoor Air Pollution In U.S., 90% of time spent

indoors; inside air often more polluted than outside air

Problems with weatherized building: little air exchange

Asbestos, carbon monoxide, formaldehyde, lead, pollen, dust, smoking

Causes diseases: emphysema, heart attacks, strokes, lung cancers

Other Air Quality Issues Ozone Depletion

Ozone in the stratosphere is “good ozone”

Shields us from harmful ultraviolet light

Skin cancer and cataracts

Chlorofluorocarbons Used as refrigerants, cleaning solvents, propellants 1970s – discovery that average concentrations of

Ozone in the stratosphere were declining

UV radiation breaks down CFC molecules, releasing atomic chlorine. A free Chlorine atom reacts with an ozone molecule,

converting it from O3 to O2. One chlorine atom can break apart more than 100,000

ozone molecules.

Chlorofluorocarbons CFCs take 10-20 years to make it into the

stratosphere. Can react with ozone for up to 120 years.

1970s – CFCs as propellants in spay cans banned in US

1987 – Montreal Protocol No increase in CFC production 50% reduction of production by 2000

1991 – DuPont announced new refrigerant 1996 – US stopped producing CFCs

Control of Air Pollution Different Approaches

Regulations on auto industry Fines to enforce bans Switch from high sulfur coal to low sulfur coal Switch to oil, gas, wind, solar, nuclear power “Scrubbers” on smoke stacks to remove sulfur

after use expensive -- $200 million per power plant

Much of regulation done under Clean Air Act

Clean Air Act (1970, 1977, 1990)Control requirements the federal government implements and states administerAll sources subject to ambient air quality regulation (NAAQS)New sources subject to more stringent controlsHazardous pollutants and visibility reducing emissions regulatedAugust 2003 changes reduce control

no pollution control devices if “routine maintenance” repairs are < 20% of the replacement value of the entire process unit

Clean Air Act Since Clean Air Act passage, EPA reports air

pollution cut by 1/3 and acid rain cut by 25%.

EPA estimates human health, welfare, and environmental benefits have outweighed costs by 40 to 1.

Old coal-fired power plants and SUVs, diesel trucks and buses are still major problems

Improvement in Air Quality 4/5 primary air

pollutants decreased since 1970

Nitrogen oxides per vehicle down, but overall emissions increased due to larger number of cars

Lead emissions way down after switch to unleaded gasoline

Points to know – Nov 291) Know the types and proportions of the gases that make up

the atmosphere. In which zone of the atmosphere does weather take place? Which contains ozone?

2) Distinguish between primary and secondary air pollutants. What are the 5 major primary air pollutants, where do they come from, and what problems do each cause?

3) What is photochemical smog, and how do thermal inversions contribute to the problem?

4) Why should we be concerned with indoor air pollution?5) Distinguish between “bad” ozone and “good” ozone. What

is causing depletion of the “good” ozone?6) What does the Clean Air Act regulate, and how successful

has it been?