Bad air day: more than 142 million Americans, or 50 percent of the U.S. population, breathe grade "F" air. The American Lung Association's state of the Air 2002 Report studied air quality in 678 counties, and 400 flunked. What's choking the air? An invisible gas--ground-level ozone. Read the graph below, then check out ozone chemistry, and test your pollution know-how. (Earth science: ozone/air pollution).What's Bad Air? The U.S. Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and (EPA EPA eicosapentaenoic acid.
n.pr See acid, eicosapentaenoic.
n. ) monitors air quality daily. And one major pollutant pol·lut·ant
Something that pollutes, especially a waste material that contaminates air, soil, or water. they keep an eye on is ozone. At unhealthy levels, ozone can trigger lung irritations and breathing problems in merely four hours of outdoor activities. Ozone is measured in parts per million parts per million
mg/kg or ml/l; see ppm. (ppm)--the number of ozone molecules for every million molecules of air mixture. Here's how the EPA ranks ozone concentration in the air: good (0.0 to 0.064 ppm); moderate (0.065 to 0.084 ppm); unhealthy for sensitive groups (0.085 to 0.104 ppm); unhealthy (0.105 to 0.124 ppm); and very unhealthy (0.125 ppm and above). "To increase public awareness we've put EPA's findings in terms that more people can relate to, like school grades," says Janice Nolen, Director of National Policy at the American Lung Association The American Lung Association (ALA) is a non-profit organization that "fights lung disease in all its forms, with special emphasis on asthma, tobacco control and environmental health". . And grade "F" counties had at least 10 days with ozone levels above 0.085 ppm over three years.
How "Bad" Ozone Forms
Naturally occurring ozone gas, which resides 10 to 17 kilometers (6 to 10 miles) above Earth's surface Noun 1. Earth's surface - the outermost level of the land or sea; "earthquakes originate far below the surface"; "three quarters of the Earth's surface is covered by water"
surface , offers protection from the sun's harmful ultraviolet (UV) rays. Ground-level ozone, although composed of the same chemical formula (three atoms of oxygen), is a harmful air pollutant and lung irritant ir·ri·tant
Causing irritation, especially physical irritation.
A source of irritation.
n 1. an agent that causes an irritation or stimulation.
2. . It's also the primary ingredient of urban smog. Here's how "bad" ozone is made.
1 Motor vehicle exhaust and industrial emissions spew nitrogen oxides (NOx)-including nitrogen dioxide nitrogen dioxide
A poisonous brown gas, NO2, often found in smog and automobile exhaust fumes and synthesized for use as a nitrating agent, a catalyst, and an oxidizing agent.
Noun 1. (NO)--into the air.
2 The sun's UV rays and air temperature above 20[degrees]C (68[degrees]F) convert NO2 into one molecule of nitric oxide nitric oxide or nitrogen monoxide, a colorless gas formed by the combustion of nitrogen and oxygen as given by the reaction: energy + N2 + O2 → 2NO; m.p. −163.6°C;; b.p. −151.8°C;. (NO) and one atom of oxygen (0): NO2 + UV sunlight = NO + O
3 The single oxygen atom combines with molecular oxygen (O2) in the air to form three atoms of oxygen, or ozone (O3): O + O2 = 03
4 In clean air, the NO reacts with O3 to form NO2 and O2: NO + O3 = NO2 +O2. Ozone is broken down.
5 But in polluted pol·lute
tr.v. pol·lut·ed, pol·lut·ing, pol·lutes
1. To make unfit for or harmful to living things, especially by the addition of waste matter. See Synonyms at contaminate.
2. areas, volatile organic compounds volatile organic compound Environment Any toxic cabon-based (organic) substance that easily become vapors or gases–eg, solvents–paint thinners, lacquer thinner, degreasers, dry cleaning fluids (VOCs)--emitted from automobile exhaust, power plants, solvents in paints, factories, dry cleaners, and even vegetation, like trees--interfere with Step 4. VOCs react with NO, converting it back to NO2:
VOC (Vertical Online Community) See vertical portal. + NO = NO2
Excess NO2 means there's less NO in the air to break down ozone (step 4). The pollutant accumulates.
WHAT DO YOU KNOW ABOUT YOUR AIR?
Check out the diagram above and graph at left to correctly answer the following questions:
1. Which of the following describes lower atmospheric ozone?
a. It occurs at ground level.
b. It protects Earth against UV rays.
c. One molecule contains two oxygen atoms.
d. One molecule contains two nitrogen atoms.
2. Which of the following statements are true?
a. The combination of motor vehicle and industrial emissions alone are enough to form "bad" ozone.
b. Sunlight and air temperature play a role in converting car and factory emissions into "bad" ozone.
c. A molecule of ozone contains one atom of nitric oxide.
d. An excess of nitrogen dioxide in the air causes more "bad" ozone to form.
3. Ozone is measured in parts per
4. From 1998 to 2000, Fresno County had a total of 231 days with ozone levels above
a. 0.065 ppm.
b. 0.85 ppm.
c. 0.125 ppm.
d. 0.350 ppm.
5. Why do you think seven of the 10 most ozone-polluted counties in the U.S. are in California?
To learn more about ozone: www.epa.gov/airnow For more on the State of the Air 2002: www.stateoftheair.org
THE 10 MOST DZONE-POLLUTED COUNTIES IN THE U.S. TOTAL NUMBER OF DAYS WITH UNHEALTHY LEVELS OF OZONE RANKING POPULATION (1998-2000) 1 San Bernardino, CA 1,669,934 270 2 Kern, CA 642,495 250 3 Fresno, CA 763,069 231 4 Riverside, CA 1,530,653 199 * 5 Tulare, CA 358,470 222 6 Harris, TX 3,250,404 142 7 Fulton, GA 744,827 117 8 Los Angeles, CA 9,329,989 110 * 9 Merced, CA 200,745 112 10 Sevier, TN 65,783 111 * These counties rank as more polluted than the ones below them even with fewer total days of high-level ozone. Their ranking combines fewer days with much higher ozone levels. Note: Table made from bar graph.
1. a 2. b and d 3. d 4, b 5. Answers may vary, but may include California's high number of vehicles on the road and generally warm climate, a perfect combination to form excessive ozone.