Air Pollution

1. Air Pollution Chapter 18-19 There is no place on Earth that isn’t affected by air pollution…

2. Air pollution: presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems, human-made materials or to alter climate • Ranges from annoying to lethal • Refers to pollution in the troposphere • Natural sources • Dust, wildfires, volcanic eruptions • Human sources • Industrialized and urban areas • fossil fuel burning

3. Primary Pollutants: chemicals or substances emitted directly into the air from natural sources and human activities • Carbon monoxide, carbon dioxide, sulfur dioxide and nitric oxides; particulate matter; VOCs (natural sources—terpenes, plant fragrance) • Secondary Pollutants: primary pollutants react with one another and natural components to form harmful chemicals, often in the presence of sunlight and water • Ozone, acid deposition (sulfates and nitrates) • To determine and monitor Air Quality, the EPA actively monitors… • carbon monoxide • ozone • lead • nitrogen dioxide • particulate matter (also known as particle pollution) • sulfur dioxide

4. Major Air Pollutants • Carbon Oxides • Carbon Dioxide: from fossil fuel burning (major pollutant); is a greenhouse gas that impacts climate; required for photosynthesis; colorless and odorless • Carbon Monoxide: from combustion of carbon (exhaust, forest burning, fossil fuels, tobacco smoke); Limits oxygen binding in hemoglobin which can result in heart attack, asthma, emphysema, nausea and death; colorless and odorless—dangerous indoor air pollutant

5. Nitrogen Oxides (NOx) and Nitric Acid • Nitric Oxide (NO): combustion in cars, coal burning, lightning, part of soil and water (nitrogen cycle); colorless and odorless • Nitrogen Dioxide (NO2): nitrogen monoxide reacts with oxygen (NO2); reacts with water to form nitric acid and nitrate salts (acid deposition); forms photochemical smog (with sunlight); helps in the formation of tropospheric ozone; stinky, reddish-brown gas • Nitrous Oxide (N2O): greenhouse gas from fertilizers and animal wastes, also fossil fuel burning ** all are irritants to eyes, nose and throat, aggravate asthma and bronchitis; suppress plant growth and harm aquatic life

6. Sulfur Dioxide and Sulfuric Acid • Sulfur Dioxide (SO2): 1/3 comes from natural sources (sulfur cycle), the rest is anthropogenic (coal burning, oil refining, smelting); corrosive gas • Sulfuric Acid: forms when SO2 reacts with water in the atmosphere, then falls as acid deposition (acid rain). **Aggravate breathing problems (respiratory irritant), decrease plant growth, corrosive

7. Particulates • Suspended particulate matter (solid particles and liquid droplets); particles smaller than 10 micrometers are regulated by the EPA as air pollution (not filtered by nose/throat) • Outdoor: dust, wildfires, sea salt, coal/oil burning, cars (especially diesel), construction; road dust, rock crushing; volcanic activity • Indoor: cigarettes, burning inside (developing countries) **Aggravate eyes, nose, and throat, damage lungs, asthma/bronchitis, genetic mutations, and cancer (premature death) **Reduces the amount of incoming solar radiation (weather)

8. Ozone (O3) • Secondary pollutant that contributes to photochemical smog • Tropospheric ozone bad. Stratospheric ozone good. • Ozone thinning is the stratosphere…which increases the amount of UV radiation that reaches us • Damages living tissue • Results from release of CFCs and other Freons…from coolants and aerosols • Montreal Protocol—Limit these chemicals in manufactured products **Coughing and breathing problems (asthma and emphysema), lung/heart disease, irritant; damaging to rubber and plastic

9. Volatile Organic Compounds (VOCs) • Organic compounds (hydrocarbons) that exist as gases in the atmosphere • Give off strong aroma (paint, perfume, gasoline, flatulence) • Help in formation of smog, not all hazardous…but some have the potential to be harmful • Ex. Methane—greenhouse gas from landfills, cows, decomposition, oil and gas burning/refining • Others include benzene, industrial solvents, gas and plastics

10. Mercury: found in coal and oil, released from fossil fuel burning, can settle out into water. Seeing bioaccumulation into food chains. • Toxin for central nervous system • Lead: occurs naturally in rocks and soils, also present in fuels and paints. • Toxic to central nervous system (children), affects learning, concentration, and intelligence

11. Factors Affecting Air Pollution • Increase air pollution • Buildings break up wind • Hills/mountains decrease air flow • High temperature increases reactions • Emissions of VOCs increase smog formation • Temperature inversions (warm air over cool) • Decrease air pollution • Heavy particles settle out of air • Rain/snow cleanse air • Salty sea spray washes air • Winds mix air • Pollutants removed by reactions

12. Acid Deposition • Air pollutants mix with water in air to form acidic precipitation (acid rain) • Nitrogen and sulfur oxides—form nitric and sulfuric acid (pH ~5) • Has been occurring since the Industrial Revolution • Usually a regional problem…downwind of coal burning facilities • Pollutants are moved by winds • Damages statues, buildings; causes respiratory diseases, leach toxic metals into the environment from rocks; harmful to aquatic ecosystems, hurts agriculture, and weakens forests and plants • Reduced by limiting emissions of pollutants (alternative energy sources)

13. Smog • Industrial • Unhealthy mix of sulfur dioxide and sulfuric acid and solid particles • Comes from coal burning in large quantities • Rarely a problem in developed countries…big problem in developing (China) • Sulfur dioxide and sulfates mostly; “grey smog” • Photochemical • Mixture of primary and secondary pollutants formed under the influence of UV radiation • “brown smog”—made up mostly of ozone

14. Indoor vs. Outdoor Air Pollution • Indoor Air Pollution from burning wood, charcoal in open fires or poorly designed stoves; cigarette smoke • Carbon monoxide and particulates • Impacts high poverty/poor countries • Sources include: • Tobacco smoke • formaldehyde • Radon gas • Fine particulates • Pesticide residues • Lead • Organic solvents • Living organisms (mites, roaches) • Mold and fungal spores

15. Radon Gas • Colorless, odorless radioactive gas that is produced by the radioactive decay of uranium-238 (from underground rock) • Only problematic in certain areas of the country • Can seep through cracks in the foundation and build up to harmful levels in air, or seep into groundwater • Damages lung tissue and lead to cancer (second leading cause of lung cancer) • Radon-222 decays to Polonium-210 (harmful/carcinogen)

16. Dealing with Air Pollution • Clean Air Act: set aside air pollution regulations • EPA monitors pollutants and sets standards for emissions • EPA's mission is to protect human health and the environment. To achieve this mission, EPA implements a variety of programs under the Clean Air Act that focus on: • reducing outdoor, or ambient, concentrations of air pollutants that cause smog, haze, acid rain, and other problems; • reducing emissions of toxic air pollutants that are known to, or are suspected of, causing cancer or other serious health effects; and • phasing out production and use of chemicals that destroy stratospheric ozone. • These pollutants come from stationary sources (like chemical plants, gas stations, and powerplants) and mobile sources (like cars, trucks, and planes). • Buy and sell pollution allotments • Prevention in best solution! • Improve fuel efficiency standards • Alternative energy sources • Educate public about pollution

17. Air Quality Index • National Ambient Air Quality Standards • EPA sets standards for pollutants harmful to humans or the environment (clean air act) • Primary standards protect public health • Secondary standards protect public welfare • Carbon Monoxide, Lead, Particulates, Ozone, Nitrogen Dioxide and Sulfur Dioxide