Chapter 15: Air Pollution

1. Chapter 15: Air Pollution By Megan Daly, Jordan Finci, and Collin Brady

2. Case Study

3. Case Study: When Is a Lichen Like a Canary? • 19th century coal miners- used Canaries in coal mines to listen to their singing. • Singing- warning signal. When stopped, air contained methane which could ignite and explode. • Today- use sophisticated equipment, but living things can also warn us of bad air. • Lichens- consist of fungus and an alga living together in mutualistic partnership. Widespread and long lived. • Biological indicators of air pollution- continually absorb air as source of nourishment • Help track pollution to source: • highly polluted=no lichen/gray-green crusty lichen • Moderate air pollution=orange crusty lichens • Clean air- leafy lichens • Examples • Chernobyl- People eat reindeer, determine which of remaining reindeer to move by analyzing lichens to pinpoint contaminated areas.

4. 15.1 The Structure of Science and the Atmosphere

5. The Troposphere • This is the atmosphere’s innermost layer • Made up of nitrogen, oxygen and small amounts of water vapor and carbon dioxide • 75-80% of air mass is found in troposphere • The troposphere also plays a key role in weather and climate

6. The Stratosphere • The second layer of the atmosphere (17-48km above surface) • The ozone here filters out most of sun’s UV radiation (prevents 95% of UV rays from reaching earth’s surface) • Almost twice the size of the troposphere, but contains less matter • Similar composition except stratosphere contains 1/1,000 concentration of water vapor and significantly more ozone

7. 15.2: Outdoor Air Pollution

8. 15-2 Outdoor Air Pollution • Air Pollution- presence of chemicals in the atmosphere in concentrations high enough to harm organisms and materials and to alter climate. • Effects- range from annoying to lethal • Air pollutants- Natural + Human sources • Natural- dust blowing off the earth’s surface, forest fires, volcanic eruptions, volatile organic chemicals released by some plants, the decay of plants, and sea spray • Spread out, rarely reach harmful levels (exceptions: volcanic eruptions and some forest fires) • Human- since discovery of fire, inputs increased when when we began extracting and burning coal. • Today, most outdoor pollutants from humans come from urban areas and the burning of fossil fuels in power plants and factories and motor vehicles. • Can reach harmful levels in troposphere, especially urban areas

9. Outdoor Air Pollution Continued… • Primary pollutants- emitted directly into the troposphere in a potentially harmful form. (Examples: soot, carbon monoxide) • Secondary pollutants- primary pollutants reacting with one another or basic components of air to form new pollutants • According to the World Health Organization (WHO), 1/6 people on earth (1.1+ billion), lives in an urban area where outdoor air is unhealthy to breathe • Most areas- air pollution control laws poorly enforced or don’t exist

10. Outdoor Air Pollution Continued… • US and other developed countries- government-mandated standards set maximum allowable atmospheric concentrations for six conventional air pollutants commonly found in outdoor air. • 6 pollutants: carbon monoxide (CO), nitrogen dioxide(NO2), sulfur dioxide(SO2), suspended particulate matter(SPM), ozone(O3), and lead • Most scientists add two other chemicals • volatile organic compounds (VOCs, mostly hydrocarbon, photochemical smog in cities), and carbon dioxide (CO2, increase troposphere temperature and change climate) • Many oil and coal companies against adding these- would have to spend more money controlling emissions. • 12 US stats sued EPA for failure to regulate CO2 emissions. Some states passing own laws to regulate it.

11. 15.3: Photochemical and Industrial Smog

12. Photochemical Smog • Mix of air pollutants formed by reaction of nitrogen oxides and hydrocarbons under influence of sunlight • VOCs + NO2 + heat + sunlight=ground level ozone, oxidants, other pollutants • Formed in car engines, coal power plants • Has to exposed to UV radiation in order for the photochemical smog

13. Photochemical Smog • Increase in temperature can lead to higher levels of ozone and the components of smog • All modern cities suffer, but more common in areas with sunny, dry climates and a lot of cars • (1999 study) if 400 million people in China drive gas powered cars in 2050, the resulting photochemical smog produced could cover entire western Pacific and extend to US

14. Industrial Smog • Mix of sulfur dioxide, sulfuric acid, solid particles emitted by burning coal and oil • Caused by burning of coal and oil • Has grey color from suspended solid particles

15. Industrial Smog • Today, rarely a problem in developed countries • Coal/oil now burned in large boilers with pollution control or with smoke stacks that transfer pollutants • In developing countries, lots of pollution • Lots of coal burned without pollution control

16. Asian Brown Cloud • Industrial smog across India, Bangladesh, and China • Caused by emission of ash, smoke, and dust

17. Natural Factors that Reduce Air Pollution • Rain and snow cleanse air • Why cities with dry climate more prone to photochem smog than cities with wet climates • Sea spray from oceans can wash out particulates • Wind can blow pollutants away • Dilute them by mixing with clean air

18. Factors that INCREASE air pollution: • Urban buildings can slow wind speed/reduce removal of pollutants • Hills/mountains can reduce flow of air • Leads to build up of pollutants • High temperatures promote chem reactions leading to photochemical smog formation

19. Grasshopper Effect • Atmospheric distillation that transfers pollutants to poles • when compounds that help dilute pollutants evaporate from ground areas and deposited into other places • Deposited in oceans, carried to higher latitudes, near poles • By atmospheric currents and oceanic currents

20. Temperature Inversion • Usually: air near surface warm, rises to mix with cooler air above it • Disperses pollutants • Sometimes: warm air can lie above cool air, creating temperature inversion • Air does not mix, so pollutants concentrate • Some areas more prone to temp. inversions, like LA basin • sunny climate, mountains and ocean, city with millions of people

22. 15.4: Regional Outdoor Air Pollution from Acid Deposition

23. Acid Deposition • Sulfur dioxide, nitrogen oxides, particulates react to produce acidic chemicals • Coal burning power plants use tall smokestacks • Reduce local pollution, but increase regional • Form acidic substances that remain in atmosphere • Acidic particles descend to earth through wet or dry deposition • Wet: acid rain, snow, fog • Dry: particles

24. Harmful Effects of Acid Deposition • Contributes to human respitory diseases (like asthma) • Can leach toxic metals into drinking water • Damage statues, buildings, monuments • Decreases atmospheric visibility • Can kill fish • Harm forests/crops

25. Ways to Reduce Acid Deposition • Best solutions preventative • Reduce: air pollution, coal use • Increase: usage of natural gas, renewable energy resources • Burn low sulfur coal • Remove certain chemicals from smokestacks/car exhaust

26. Section 5 Indoor Air Pollution

27. Indoor Air pollution • Often poses much greater threat to human population than outdoor air pollution • Levels of 11 common pollutants are generally two to five times higher indoors than outdoors, sometimes up to 100 times higher • Air pollution in cars is very high, especially in traffic jammed urban areas • Most people in developed countries spend 70-98% of their time indoors (includes vehicles)

28. Exposure to Radon Gas • Radon-222 is a radioactive gas found in soil and rocks • It has been known to seep into houses and increase the risk of lung cancer • Common in underground deposits of uranium, phosphate, granite, and shale • Radon-222 is harmless when exposed outdoors, bud is extremely harmful when released indoors

29. 15.6: Harmful Effects of Air Pollution

30. 15-6 Harmful Effects of Air Pollution • Respiratory system- number of mechanisms to protect from air pollution. • Hair in nose larger particles, sticky mucus lining in upper respiratory tract for small particles • Sneezing and coughing expel contaminated air and mucus • Cilia- hundreds of thousands of tiny mucus-coated hair like structures in upper respiratory tract • Prolonged or acute exposure to air pollutants- overload or break down defenses (Ex: smoking) • Lead to diseases such as asthma. 17+ million Americans have asthma, 5 million younger than age 5 • Lung cancer and chronic bronchitis over time can form from persistent inflammation and damage • Symptoms- mucus build up, painful coughing, shortness of breath. Deeper damage to lungs- emphysema, irreversible damage to air sacs • People with respiratory diseases especially vulnerable

31. Harmful Heath Effects of Pollutants • Air pollutants damage materials and human lungs and worldwide prematurely kill at least 3 million people each year • 8,200 deaths per day. 2.8 million (93%) result from indoor air pollution. • In US, EPA estimates annual deaths from indoor and outdoor air pollution range from 150,000-300,000 people • Equal to two fully loaded 400-passenger jumbo jets crashing each day with no survivors. • Most deaths come from inhalation of fine and ultrafine particles from coal-burning power plants, mostly in eastern half of US • EPA recent studies estimate 125,000 Americans get cancer from breathing soot-laden diesel fumes from buses and trucks. • 1 year, a large diesel powered bulldozer can produce as much air pollution as 26 cars.

32. Section 7 Preventing and Reducing Air Pollution

33. Air Pollution Laws in the U.S. • The Clean Air Acts in the United States have greatly reduced outdoor air pollution from six major pollutants • Laws were passed in 1970, 1977, and 1990 • Regulated by the EPA • Unfortunately smog levels didn’t drop from 1993-2002 and EPS estimates that airborne fine particles cause over 15,000 premature deaths per year in U.S., and 95,000 cases of bronchitis

34. U.S. Air Pollution Laws • Environmental scientists applaud the success of U.S. air pollution laws but have suggested several ways to make them more effective • Rely on prevention rather than cleanup • Increases fuel efficiency in cars and other vehicles • Reduce emission from two-cycle gasoline engines • More seriously deal with the problem of indoor air pollution • Better enforcement of the Clean Air Acts

35. Using Marketplace to Reduce Air Pollution • Allowing producers of air pollutants to buy and sell government air pollution allotments in the marketplace can help reduce emissions • Clean Air Act limits the amount of SO₂ that each coal burning power plant can emit each year • Cap and Trade Program

36. Reducing Outdoor Air Pollution • There are a number of ways to prevent and control air pollution from coal-burning facilities and motor vehicles • Burn low-sulfur coal or just remove sulfur from coal • Convert coal to a liquid or gaseous fuel • Shift to less polluting fuels • Tax each unit of pollution produced • Remove pollutants after combustion

37. Reducing Indoor Air Pollution • Little Effort has been devoted to reducing indoor air pollution even though it poses a much greater threat to human health • Limit smoking to well ventilated areas • Prevent radon infiltration • Place office machines in well ventilated areas • Increase intake of outside air • Change air more frequently • Circulate building’s air through rooftop greenhouses • Adjustable fresh air vents for work spaces

38. What is the Next Step? • We need to focus on preventing air pollution, with emphasis on sharply reducing indoor air pollution in developing countries • Improve energy efficiency to reduce fossil fuel use • Rely more on renewable energy • Reduce or ban indoor smoking • Develop simple and cheap tests for indoor pollutants such as particulates, radon, and formaldehyde