BI 105A Environmental Biology

1. BI 105AEnvironmental Biology Professor Jill Nissen Montgomery College Fall 2006

2. Air Pollution Chapter 20

3. Air Pollution Air pollution consists of gases, liquids, or solids present in the atmosphere in high enough levels to harm humans, other organisms, or materials

4. Seven Major Classes of Air Pollutants Table 20.1, p. 456: • Particulate Matter • Nitrogen Oxides • Sulfur Oxides • Carbon Oxides • Hydrocarbons • Ozone • Air Toxics (Hazardous Air Pollutants)

5. Primary vs. Secondary Air Pollutants Primary air pollutants: • Harmful chemicals that enter directly into the atmosphere • Carbon oxides • Nitrogen oxides • Sulfur dioxide • Particulate matter • Hydrocarbons Secondary air pollutants: • Harmful chemicals that are produced from chemical reactions involving primary air pollutants • Ozone • Sulfur trioxide

6. Sources of Primary Air Pollutants Transportation is the major contributor to air pollution

7. Urban Air Pollution Industrial Smog • Traditional smoke pollution (Smoke + Fog = Smog) • Consists primarily of sulfur oxides and particular matter • Coal burning factories are main source Photochemical Smog • Brownish orange haze • Formed by complex chemical reactions involving nitrogen oxides, hydrocarbons, and sunlight (photo = light) • Automobiles are main source

8. Thermal Inversion • Normally, air is warmed near Earth’s surface and rises, carrying toxic pollutants with it • In a thermal inversion (temperature inversion) cool air is trapped below a cap of warmer air, and toxic pollutants remain trapped near Earth’s surface • Cities in valleys, near the coast, or on the leeward side of mountains are most susceptible (Los Angeles, Denver, Mexico City)

9. Urban Heat Islands Urban Heat Islands (p. 217-218) • Air in urban areas is warmer than air in surrounding suburban and rural areas • Affects local weather conditions, increasing thunderstorms • Contributes to the formation of dust domes, a buildup of pollutants over cities

10. Effects of Air Pollution Air pollution • Injures organisms • Reduces visibility • Attacks and corrodes materials (metal, stone, plastics, rubber, fabrics, etc.) • Reduces productivity of crops • Contributes to global warming, ozone depletion, and acid deposition

11. Air Pollution and Human Health In general, air pollutants • Irritate eyes • Inflame respiratory tract • Suppress the immune system

12. Health Effects of Specific Air Pollutants Sulfur dioxide, nitrogen dioxide, and particulate matter • Constrict airways, impairing ability to exchange gases • People with emphysema or asthma are most at risk Carbon monoxide • Combines with hemoglobin and reduces blood’s ability to transport O2 – headaches, fatigue, death • Pregnant women, infants, and people with heart or respiratory disease are most at risk Ozone • Causes burning eyes, coughing, chest discomfort

13. Children and Air Pollution Air pollution is a greater health threat for children than adults because • Their lungs are in the developmental stage • They have a higher metabolic rate • They breathe twice as much air as adults

14. Smoking Smoking • Causes lung cancer, emphysema, and heart disease • Contributes to heart attacks, stroke, and other cancers • Results in premature death for 500,000 people in the U.S. each year Passive smoking (second hand smoke) • Causes increased incidence of lung cancer, respiratory infections, and allergies • Infants and children, pregnant women, the elderly, and people with chronic lung disease are most at risk

15. Controlling Air Pollutants • Improve energy efficiency and conservation • Make the switch from coal power to natural gas, or solar power • Use smaller, more fuel efficient cars or mass transit • Require vehicle emissions inspection • Install pollution reduction devices • Filters or scrubbers for factories • Catalytic converters for automobiles

16. Reducing Emissions

17. Air Pollution Legislation • Overall, air quality in the U.S. has improved since 1970 due to the Clean Air Act • First passed in 1970 • Amended in 1977 and 1990 • Authorizes the EPA to set limits on the amount of specific air pollutants permitted anywhere in the U.S. • Still, many areas in the U.S., including Maryland, have unacceptably high levels of pollutants (Nonattainment areas)

18. Indoor Air Pollution Indoor Air pollution • Air in enclosed spaces (auto, home, school, office buildings) may have higher levels of air pollutants than outdoor air • Indoor air pollutants include radon, cigarette smoke, carbon monoxide, nitrogen dioxide, formaldehyde, pesticides, cleaning products, ozone, asbestos, allergens, and pathogens

19. Radon • Radon is a colorless, tasteless radioactive gas produced naturally by Uranium decay in the Earth’s crust • 1 in 15 homes in the U.S. have high enough levels of radon to warrant corrective action • Breathing low levels of radon can lead to lung cancer • Radon is the most serious indoor air pollutant

20. Asbestos • Asbestos is a mineral fiber that has been used in construction materials for insulation and as a fire-retardant • Most commonly found in older homes • Exposure to asbestos can lead to long-term risk of chest and abdominal cancers and lung diseases • Asbestos is only a major health risk when it is exposed and crumbling, therefore it is best left alone if it is in good condition

21. Health Effects of Indoor Air Pollution Why is indoor air pollution a particular concern? • Urban residents spend as much as 90-95% of their time indoors • Symptoms caused by indoor air pollution often resemble colds, flu, or allergies • Coughing • Sneezing • Wheezing • Nausea • Dizziness • Headaches

22. Sick Building Syndrome • Sick Building Syndrome is defined as eye irritation, nausea, headaches, respiratory infections, depression, and fatigue caused by the presence of air pollution inside office buildings • No specific illness can be found • Symptoms improve after leaving the building • Causes lost work time, diminished productivity, and increased health costs

23. Improving Indoor Air Quality There are three basic strategies to improve indoor air quality: • Source Control • Seal or enclose pollution sources • Restrict smoking • Replace water-stained carpet and ceiling tile • Improved Ventilation • Open windows and doors • Use window, ceiling, and exhaust fans • Store and use paints, adhesives, solvents, and pesticides etc. in well ventilated areas • Air cleaners • Clean or replace HVAC filters regularly • Install an electronic air cleaner or ionizer (these range from inexpensive table top models to sophisticated and expensive whole-house systems) • http://www.epa.gov/iaq/ia-intro.html

24. Review Objectives Types and Sources of Air Pollution• Define air pollution and distinguish between primary and secondary air pollutants.• List the seven major classes of air pollutants, including ozone and hazardous air pollutants, and describe their characteristics and effects.• Describe industrial smog, photochemical smog, temperature inversions, urban heat islands, and dust domes. Effects of Air Pollution• Relate the adverse health effects of specific air pollutants and explain why children are particularly susceptible to air pollution. Controlling Air Pollution in the United States• Summarize the effects of the Clean Air Act on U.S. air pollution. Indoor Air Pollution• Summarize the sick building syndrome.• Explain why radon is such a serious indoor air pollutant.