Chapter 6: Air

1. Chapter 6: Air “ I thought I saw a blue jay this morning. But the smog was so bad that it turned out to be a cardinal holding its breath.”Michael J Cohen, Professor of Political Science Bar Ilan University, Israel

2. 6.1 What Causes Air Pollution? • In Mexico City, children rarely use the color blue to make paintings of the sky; it is known as one of the most dangerous cities in the world for children because the air is so polluted (nearly 20 million people live there) • Clean air consists mostly of nitrogen and oxygen gases, along with small amounts of CO2and water vapor • Some areas, like Mexico City, get so polluted they tell kids to stay home from school; people who go outside must wear dust masks • When unhealthy substances are in the air it is called air pollution; most air pollution is a result of human activities; however, some air pollution comes from natural sources (ex: volcano will spew clouds of particles and sulfur dioxide into the atmosphere); other natural pollutants are dust, pollen, spores

3. Primary and Secondary Pollutants • Primary pollutant is a pollutant that is put directly into the air by human activity (ex: soot from smoke) • Secondary pollutants are formed when a primary pollutant comes into contact with other primary pollutants, or with naturally occurring substances like water vapor and a chemical reaction takes place (ex: ground-level ozone forms when the emissions from cars, trucks and natural sources react with the ultraviolet rays of the sun and then mix with the oxygen in the atmosphere)

4. Sources of Primary Air Pollutants • Household products, power plants and motor vehicles are sources of primary air pollutants (carbon monoxide, sulfur dioxide, nitrogen oxide and chemicals called volatile organic compounds (VOCs). • Sources of pollutants: Vehicles: carbon monoxide (important component of the exhaust), nitrogen oxide and VOCs; Coal-burning power plants: nitrogen oxide; Coal and Oil burning, power plants, refineries, metal smelters: sulfur dioxide • Particulate matter also pollutes the air; divided into fine particles (enter from fuel burned by vehicles and coal-burning power plants) and coarse particles (cement plants, mining operations, incinerators, wood-burning fireplaces, fields and roads)

5. The History of Air Pollution • Air pollution is nothing new; burning fuels put pollutants into the air [ex: Rome, 2000 years ago, philosophers complained of the foul air; England, (circa: 1273) banned burning a particular coal] • Air quality is much worse today because modern industrial societies burn large quantities of fossil fuels (urban areas are from motor vehicles and industry)

6. Motor Vehicle Emissions • Over 1/3 of our air pollution comes from gasoline burned in motor vehicles • Approximately 70% of air pollution comes from by cars and trucks, the rest by commercial vehicles; In 1995, US vehicles traveled over 2 trillion miles, by 1998, Americans drove over 2.6 trillion, 90% driven by passenger cars, the rest by trucks and buses

7. Controlling Vehicle Emissions • Clean Air Act (1970, strengthened in 1990) gave the EPA the authority to regulate automobile emissions • EPA required gradual elimination of lead in gas, resulting in more than a 90% drop of lead pollution; • Catalytic converters (required in automobiles) clean exhaust gases of pollutants before they are able to exit the tailpipe; EPA estimates that vehicles burn fuel 35% more efficiently, with 95% fewer emissions of pollutants (except CO2) than 30 years ago • Driving less is an effective way of reducing air pollution (ex: carpooling with one other person would reduce 33 million lbs. of CO2 into the air • Car manufacturers are making cars to run on fuels which cause less air pollution (solar, batteries, hydrogen, natural gas) • Brazil has over 4 million cars that run on ethanol (made from remnants of sugarcane plants) • Ethanol is less polluting; burns to form CO2 and H2O

8. California Zero-Emissions Vehicle Program • Zero-emission vehicles have no tailpipe emissions, no emissions from gasoline and no emission-control systems that deteriorate over time. • By 2016, California requires 16% of all vehicles sold to be zero-emission vehicles (SUVs, trucks, sm. vans and autos); at present, ZEVs (electric vehicles) and advanced battery vehicles are being demonstrated by major automobile companies; vehicles powered by hydrogen are being developed; some partial zero-emission vehicles are included (hybrid-electric, methanol fuel cells. • Zero-emission programs have also been adopted in Maine, Massachusetts, New York and Vermont.

9. Industrial Air Pollution • Many industries and power plants generate electricity by burning fossil fuels • Burning fossil fuels cause large quantities of oxides to be released into the air; electric power plants produce at least 2/3 of all sulfur dioxide, 1/3 of all nitrogen oxides, and ½ of the particulates • VOCs (volatile organic compounds) form toxic fumes; petroleum refineries put VOCs into the air when converting crude oil into refined fuel (gasoline); auto and airplane manufacturing release VOCs which vaporize (spray painting parts)

10. Regulating Air Pollution From Industry • Clean Air Act requires industries to use scrubbers or other pollution control devices • Scrubbers remove some of the more noxious substances; gases are moved through a spray of water that dissolve many pollutants • Electrostatic precipitators (used in cement factories and coal burning power plants) remove particulates from smokestacks; 20 million tons of ash are removed every year in the US by these electrostatic precipitators

11. Smog • When air pollution hangs over urban areas and reduces visibility, it is called SMOG (smoke and fog); chemical reaction involving sunlight, nitrogen oxides and hydrocarbons. • Pollutants released by automobiles and industries are the main causes of smog • Cities, like Los Angeles, Denver and Mexico City, suffer the most from smog (dry, sunny locations with dense traffic)

12. Temperature Inversions • Air circulation usually keeps air pollution from reaching dangerous levels (sun heats the surface of the Earth and air near it, warm air rises through the cooler air, carrying pollutants away from Earth’s surface) • Sometimes pollution gets trapped near Earth’s surface (temperature inversion- air above is warmer than the air below it); traps the pollutants below with the cooler air. If a city is located in a valley (Los Angeles), the city has a higher chance of experiencing temperature inversions

13. 6.2 Effects on Human Health • Air pollution can cause serious health problems; especially, the very young, the very old and those with heart or lung problems • Air pollution aggravates existing diseases; death certificates indicate emphysema, asthma, lung cancer as causes rather than air pollution • Americans pay tens of billions of dollars a year in health costs to treat respiratory diseases attributed to air pollution

14. Short-Term Effects of Air Pollution on Health • Many of the effects of air pollution on people’s health are short-term and are reversible IF their exposure decreases • Examples of short-term exposure: headache; nausea; irritation to the eyes, nose and throat; tightness in the chest; coughing; upper respiratory infections (bronchitis, pneumonia) • Pollution can make asthma and emphysema worsen in individuals with these conditions

15. Chronic Bronchititis and Asthma • Chronic Bronchitis is the persistent inflammation of the bronchial linings; constant coughing weakens the bronchial tubes and eventually breathing becomes difficult; particulates, oxides and acids of sulfur and nitrogen are the main irritants • Bronchial asthma is a condition in which the bronchial passages constrict and become blocked with mucus; the same pollutants mentioned above are largely responsible for aggravating asthma; asthma is not caused by air pollution but the air pollutants may worsen it

16. Emphysema and Lung Cancer • Air pollution has been linked to emphysema (air sacs in the lungs lose their elasticity and can no longer push air out of the lungs, thus the exchange of oxygen and carbon dioxide is impaired); sufferers cannot perform even the simplest of tasks without gasping for air • Lung cancer is also linked to air pollution; cigarette smoking is the major cause of lung cancer; automobile exhaust and particulates also contribute to lung cancer • Non-smoking city dwellers are 3 to 4 times likely to develop lung cancer than nonsmoking residents in rural areas

17. Indoor Air Pollution • The air inside buildings is sometime worse than the air outside (Americans spend 89%of their time indoors) • Plastic and other industrial compounds are a major source of pollution (ex: carpet, building material, paint, furniture) • Buildings that have windows that open allow pollutants to circulate and pass out of the building; ones that are tightly closed up, pollutants will accumulate and reach higher levels than they could outdoors • Sick-building syndrome (buildings with poor air quality)are most often found in the desert Southwest, Southern California and Florida • Air filters in air-conditioning systems can help relieve indoor air pollution, but not all can be removed; it is best to ventilate a building with outdoor air

18. Asbestos • Asbestos is the name given to a combination of several fibers containing silica that are valued for their strength and resistance to heat (form in long, thin fibers) • Asbestos was primarily used as an insulator and as a fire retardant, also used extensively in building materials; government banned the use of most products in the early 1970’s • Also widely used to reinforce cement, make brake linings, vinyl floor tiles, residential siding, firefighters clothing, and used in commercial buildings (schools, US has spent over $40 billion to remove from buildings) • Asbestos fibers can cut and scar the lungs (asbestosis), causing victims to have trouble breathing which will lead to heart failure

19. 6.2…continued Radon Gas • Radon gas is invisible, tasteless, and odorless, and it is also radioactive; second leading cause of lung cancer in the US • Produced by radioactive decay of uranium, which occurs naturally in the Earth • It is concentrated in porous soil overlying rocks that contain radon; can enter home, offices and schools by seeping through cracks and holes in foundations and adheres to dust particles; when you inhale the dust, it enters the lungs • In the lungs, radon releases alpha particles, which destroy the genetic material in cells lining the air passages, leading to cancer, especially among smokers

20. Noise Pollution • A sound of any kind is called noise; however, some are unnecessary and can cause noise pollution (noise that affects human health and quality of life) • Examples: airplanes, construction equipment, city traffic, factories, home appliances, lawnmowers • Health problems associated with noise pollution: loss of hearing, high blood pressure, stress, loss of sleep (leads to decreases productivity at work and in the classroom)

21. Noise Pollution…continued • Noise is measured in decibels (dB). Lowest point on decibel scale is 0 dB; highest point if 180 dB; for each increase in dB intensity, the decibel level is 10 times higher than the previous level. (ex: 20 dB is 10 times higher the intensity of 10 dB, 30 dB is 100 times the intensity of 10 dB, etc.) • 120 dB is at the threshold of pain; permanent deafness may come as a result of continuous exposure to sounds over 120 dB • Ex: rocket engine 180 dB; jet engine 140dB; rock-and-roll concert 120dB; car horn 110 dB; chainsaw 100 dB; lawnmower 90dB; doorbell 80 dB; conversation 60 dB; whisper 30dB

22. Light Pollution • Unlike air or water pollution, light pollution does not present a direct hazard to human health; however, it does cause negative affects on the environment (ex: inefficient lighting diminishes our view of the night sky and in urban areas, is often much brighter than the natural sky) • Most important environmental concern of inefficient lighting is energy waste (ex: light directed upward into the night sky and lost to space – billboards, other signs that are lit from below, lighting exteriors of buildings, poor quality street lights) • One solution to energy waste: shielding light so it is directed downward, using time controls, using low-pressure sodium sources (most efficient source of light)

23. 6.3: Acid Precipitation • Suppose that one day you are hiking in the woods. You come to a lake and sit down to rest. You are looking at the lake, amazed at how clear the water is, and then you realize something is wrong. You realize there are no fish in the water.

24. What Causes Acid Precipitation? • This lake and thousands of lakes throughout the world are victims of acid precipitation, also known as acid rain. • Acid precipitation is rain, sleet or snow that contains a high concentration of acids. • When fossil fuels are burned, they release oxides of sulfur and nitrogen; when combined with water in the atmosphere, they form sulfuric acid and nitric acid • Acid precipitation falls to Earth, flows over the land, into lakes, rivers and streams killing living things (both plant and animal)

25. pH Level • A pH (power of hydrogen) number is a measure of how acidic or basic a substance is • The lower the pH, the more acidic a substance is; the higher the pH number is, the more basic the substance is; each whole number on the pH scale indicates a tenfold change in acidity • Pure water has a pH of 7.0; normal precipitation has a pH of 5.6; water is considered acid precipitation if it has a pH below 5.0 • pH of precipitation varies between locations: Scandinavia ranges between 4.3 to 4.5; Europe between 4.5 and 5.1; eastern US and Canada ranges between 4.2 and 4.8 • The most acidic precipitation in North America occurs around Lake Erie and Lake Ontario; pH levels are about 4.2

26. How Acid Precipitation Affects Soils and Plants • Plants adapt over long periods of time to the acidity of the soil they grow in; acid precipitation can cause a drop in soil and water pH; this increase is call acidification • Acidification changes the balance of soil’s chemistry; some nutrients are dissolved and washed away, aluminum and other toxic metals may be released and absorbed by roots of plants (root damage); sulfur dioxide clogs the openings on the surface of plants

27. Acid Precipitation and Aquatic Ecosystems • Aquatic animals are adapted to live in water with specific pH levels; if acid rain falls on a lake, it can change the pH level, thus killing aquatic plants, animals and fish. Aluminum can also leach out of the soil surrounding the lake, accumulating in the gills of the fish, which interferes with the oxygen and salt exchange. • Worse in the spring when snow melts; creates acid shock (rapid change in water’s pH) which results in a large number of fish dying; also affects the reproduction of fish and amphibians (produce fewer eggs which oftentimes don’t even hatch; offspring that do survive may have birth defects and cannot reproduce) • To offset the effects of acid rain, some place in the US and other countries will spray powdered lime on the lakes to help restore the natural pH of the water

28. Acid Precipitation and Humans • Acid precipitation can affect humans in a variety of ways • Toxic metals (aluminum and mercury) can be released into the soil and find their way into crops, water and fish which are then eaten by humans • Researchers believe there may be a connection between acid precipitation and respiratory problems, especially in children • Standard of living of some peoples is affected: commercial fisherman, sport fishing industries, forestry • Acid precipitation destroys buildings and historic monuments

29. International Conflict and Cooperation • One big problem in controlling acid precipitation is that pollutants may be released in one geographic location and fall to the ground in another location (ex: ½ of the acid rain falling in southeastern Canada results from pollution produced in Ohio, Indiana, Pennsylvania, Illinois, Missouri, West Virginia and Tennessee • Very difficult to solve since acid precipitation falls downward (Canada-US Air Quality Agreement was signed in 1991); both countries agreed to reduce acidic emissions that flowed across the border.