The Atmosphere and Air Quality Notes

1. The Atmosphere and Air Quality Notes

3. The Earth’s Atmosphere Troposphere • 75% of mass of atmosphere • 0 to 11 miles in altitude • 78% nitrogen, 21% oxygen • Location of Earth’s weather • Temperature decreases with altitude until the next layer is reached, where there is a sudden rise in temperature

4. Stratosphere • 11 miles to 30 miles in altitude • Calm • Temperature increases with altitude • Contains 1000x the ozone of the rest of the atmosphere; ozone forms in an equilibrium reaction when oxygen is converted to O3 by lightning and/or sunlight • 99% of ultraviolet radiation (especially UV-B) is absorbed by the stratosphere

5. Mesosphere • 30 to 50 miles in altitude • The temperature decreases with increasing altitude

6. Thermosphere • 50 to 75 miles in altitude • Temperature increases with increasing altitude • Very high temperatures

7. Air Issues Pollution Anthropogenic- Caused by man’s activities (transportation, power plants, industry)

8. Primary Pollutants Released directly into the atmosphere

9. Volatile Organic Compounds (VOC’s) • These may cause cancer. They are released by burning hydrocarbons (gasoline, etc.)

10. Nitrogen Oxides • These may cause lung irritation, bronchitis, and acid rain. They’re released by burning fuels.

11. Sulfur Oxides • These may cause emphysema, bronchitis, and acid rain, and are released by burning fuels and industry.

12. Particulates • These may irritate the respiratory system and cause cancer, and are released by combustion and industry

13. Carbon Monoxide • It may cause death and confusion. It is released from the combustion of fossil fuels.

14. Miscellaneous • Arsenic (from smelters; deadly), lead (from smelters; lowers IQ), mercury (from smelters; schizophrenia) radioactive elements.

15. Secondary Pollutants Form when primary pollutants react

16. Smog • Interaction between volatile organic compounds and nitrogen oxides. It often contains ozone, and may cause asthma and emphysema. • Comes from car emissions reacting w/ sunlight.

17. Acid Rain • Interaction between sulfur, nitrogen oxides, & water converted into H2SO4 and HNO3. • It damages buildings, weakens plants, causes plants & animals to absorb toxic metals, & causes an overgrowth (too much nitrogen) that depletes soil. It is primarily a problem in the NE U.S. and Europe. • Comes from coal power plants, industrial plants and transportation.

18. Air Quality is better in US; EPA estimates since 1970 • Particulate Matter (PM)- down 78% • Carbon Dioxide (CO2)- down 23% • Nitrogen Dioxide (Nox)- up 14% • Lead (Pb)- down 98% • Sulfur Dioxide (SO2)- down 32% Air quality is worse in developing countries: Mexico City & Beijing: air exceeds WHO standards 350 days/year

19. Natural Pollutants • We have very little control over these • Includes dust, pollen, microorganisms, smoke, and volcanic gases

20. Indoor Pollutants • These may cause dizziness, headache, and respiratory symptoms (asthma, pneumonia, bronchitis and emphysema) • Include particulates, formaldehyde, and asbestos • Radon- average level indoor 1.3 pCi/L (picocuries per liter) and “action level” is 4.0 pCi/L. Hotspots- PA, NJ,NY and NC mts0 causes lung cancer

21. Effects of Pollution • Health of humans, livestock, wildlife, plants, corrosion of metals, erosion and discoloration of stone, and disruption of soil nutrient cycles. • Amphibians and lichens are especially sensitive (indicator species)

22. Ozone Depletion Ozone is Being Broken Down • The ozone layer is being broken down by chemical reactions with halides (chlorine, fluorine, etc.) that are found in refrigerants, aerosols, etc. (Chlorofluorocarbons = CFC’s).

23. Holes in the Ozone Layer • Holes and thin areas in the ozone layer allow too much ultraviolet radiation to hit Earth.

24. Effects of UV Radiation • UV radiation damages the DNA in cells, causing skin cancer, cataracts, and plants tissue damage.

25. Global Warming/Greenhouse Effect Cause of Global Warming • Increased levels of carbon dioxide and methane build up an extra layer in the atmosphere that traps the heat from the sun. • Data on this is very controversial.

26. Benefits • Possible Benefits could be an increased productivity due to higher temperatures and availability of carbon dioxide.

27. Problems • Possible problems could be an overall climate change and melting of the ice caps.

28. Relationships Climate and Pollution • Windy areas have less air pollution than less windy areas • Cool, moist areas tend to develop into “gray air” cities due to build-up of smog • Warm, dry areas tend to develop into “brown air” cities due to the build-up of photochemical smog (high levels of ozone)

29. CHEMICAL PROCESS OF PHOTOCHEMICAL SMOG: Heat from vehicles, etc. produce nitric oxide which reacts with oxygen to form nitrogen dioxide, a gas with a choking odor. The nitrogen dioxide produces the brownish haze that hangs over many cities. CHEMICAL PROCESS OF INDUSTRIAL SMOG: When burned, the carbon in coal and oil is converted to Carbon Dioxide and carbon monoxide. The sulfur in the coal and oil react with oxygen to produce sulfur dioxide, a colorless, suffocating gas. This sulfur dioxide reacts with oxygen to form sulfur trioxide, which then reacts with water vapor in the air to produce sulfuric acid. This produces industrial smog.

30. Topography and Pollution • Mountainous areas tend to trap pollution • Flat areas tend to allow pollution to disperse

31. Temperature Inversions • A layer of warm air traps a layer of cold air underneath it; pollution is stuck in the cooler air • Often a problem in mountainous areas • Subsidence inversions are large and long-lasting • Radiation inversions are smaller and short-lived (caused by ground cooling faster than the upper air)

32. Human Impact (Positive) Pollution Control Devices • Emission Control Devices – filter particles • Scrubbers – use water to filter particles and gases • Catalytic Converters – on cars; finish burning wastes to decrease carbon monoxide levels • 1-800-453-SMOG

33. Law – Clean Air Act • 1963 - first passage • 1970, 1977 and 1990 - amended • Involves EPA • Sets standards for acceptable levels of sulfur oxides, nitrogen oxides, ozone, carbon monoxide, hydrocarbons, lead, & more • Provides pollution credits for industries that utilize pollution-control devices+ • Bush administration has relaxed rules • It established NAAQS and AQI

34. National Ambient Air Quality Standards (NAAQS) • Sets acceptable concentrations for 6 “criteria” pollutants that: • Threaten public health/the environment over broad areas (non-point) • Are emitted in large quantities • CO, Pb, Nitrogen Oxides, Ozone, Particulate Matter and Sulfur Dioxides

35. Air Quality Index (AQI) • Measures levels of 5 criteria pollutants • Forecast of daily air pollution levels • Purpose to educate and protect public- focuses on health effects • Categories: green= good, yellow= moderate, orange= unhealthy for sensitive groups, red= unhealthy, purple= very unhealthy

36. National Emissions Standards for Hazardous Air Pollutants • Regulates emissions (from point sources) • For specific substances (air toxics w/ known or suspected serious health effects (mutagens, carcinogens, neurotoxins) • Tend to be localized, from point sources • Examples: Ammonia, chlorine, asbestos, arsenic, mercury, benzene