Announcements – Oct 25

1. Announcements – Oct 25 • Test results are in.

2. CNN Booming 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.

3. 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.

4. CNN, November 16, 2004 Study links smog increase, urban deaths CHICAGO, 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.

5. Air Quality I Lecture Objectives: • What are the major types and sources of airborne pollutants? • What are the issues with ozone? • Has the Clean Air Act been effective?

6. Atmosphere • Atmosphere - air above the earth • 78% nitrogen, 21% oxygen, 1% carbon dioxide, water, other gases

7. Atmosphere • Divided into four zones: Troposphere, Stratosphere, Mesosphere, Thermosphere • Decrease in density further from Earth • Troposphere is where weather takes place • Stratosphere contains most of the ozone

8. Atmosphere • Airborne particles mix, dilute, but remain in atmosphere • Accumulate in direction of winds • Can lead to health problems

9. 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

10. Air pollutants • Primary air pollutants • Materials that when released pose health risks in their unmodified forms • Secondary air pollutants • Primary pollutants interact with one another, sunlight, or natural gases to produce new, harmful compounds

11. Primary Air Pollutants • Five major materials released directly into the atmosphere in unmodified forms. • Carbon monoxide • Hydrocarbons • Particulate matter (2.5 mm and 10 mm) • Sulfur dioxide • Nitrogen oxides • 189 substances are regulated under the Clean Air Act

12. 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

13. 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

14. 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

15. Particulates • Particulates - small pieces of solid materials and liquid droplets (2.5 mm and 10 mm) • Examples: ash from fires, asbestos from brakes and insulation, dust • Easily noticed: e.g. smokestacks • More attention, more regulation

16. 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

17. 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

18. 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

19. 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

20. 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

21. Effects of Acid Rain • Can degrade buildings and monuments made of limestone

22. 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

23. 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”

24. 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

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

27. 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

29. 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

31. Other Air Quality Issues • Ozone Depletion • Ozone in the stratosphere is “good ozone” • Shields us from harmful ultraviolet light • Skin cancer and cataracts

32. 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.

33. 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

34. 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

35. Clean Air Act (1970, 1977, 1990) • Control requirements the federal government implements and states administer • All sources subject to ambient air quality regulation (NAAQS) • New sources subject to more stringent controls • Hazardous pollutants and visibility reducing emissions regulated • August 2003 changes reduce control • no pollution control devices if “routine maintenance” repairs are < 20% of the replacement value of the entire process unit

36. 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

37. 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

38. Points to know – Nov 29 • 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? • 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? • What is photochemical smog, and how do thermal inversions contribute to the problem? • Why should we be concerned with indoor air pollution? • Distinguish between “bad” ozone and “good” ozone. What is causing depletion of the “good” ozone? • What does the Clean Air Act regulate, and how successful has it been?