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Environmental Science. Unit 3 – Air Pollution (STE 7th ed. Chapter 12). Where are we going?. 1. Air Pollution Sources Smog: Photochemical and industrial 2. Acid Deposition Sources Ecological Effects 3. Indoor Air Pollution Sources Health Effects
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Environmental Science • Unit 3 – Air Pollution(STE 7th ed. Chapter 12)
Where are we going? 1. Air Pollution • Sources • Smog: Photochemical and industrial 2. Acid Deposition • Sources • Ecological Effects 3. Indoor Air Pollution • Sources • Health Effects 4. Health Effects of Gaseous and Particulate Pollutants 5. Preventing and Controlling Air Pollution • Laws • Trends • Technology
Air PollutionHuman Inputs to Troposphere • modify Earth's gaseous nutrient cycles • N & S compounds released by burning fossil fuels • CO2 & other greenhouse gases from burning fossil fuels & clearing forests
Air PollutionHuman Inputs to Troposphere Anthropogenic vs. Natural Sources Anthropogenic Natural Mt. Pinatubo, PhillipinesJune, 1991 A coal barge on the Monongahela River moves past a U. S. Steel Corporation coke plant at Clairton, Pennsylvania, 1973 Wildfires across Oklahoma and TexasJan 2, 2006
Air PollutionSources Anthropogenic sources: fossil fuels (stationary source) motor vehicles (mobile sources) Natural: Volcanoes Forest Fires Vegetation Oceans
Air PollutionPrimary and Secondary Pollutants Primary • Carbon monoxide (CO) • Nitrogen oxides (NOx) • Sulfur dioxide (SO2) • Volatile Organic Compounds (VOC’s) • Particulates (PM) • Secondary • Ozone (O3) • Sulfur tioxide (SO3) • Nitric acid (HNO3) • Sulfuric acid (H2SO4) • Hydrogen Peroxide (H2O2) • PAN Secondary pollutants are reaction products
Air PollutionParticulate Matter DLS PM Movie
Sources Source: EPA National Emissions Inventory (NEI) Air Pollutant Emissions Trends Data
Air PollutionSmog This 1963 photo shows a massive smog episode in New York City (Photo: AP/Wide World Photo, EPA Journal Jan/Feb 1990.)
Air PollutionLondon Smog 1952 CNN 2004
Air PollutionLondon Smog 1952 • Smog = smoke + fog • Over 4,000 deaths were attributable to the Great London Smog of December 1952
Air Pollution‘Donora Death Fog’ 1948 • SE of Pittsburgh, surrounded by mountains in the Monongahela valley (subject to frequent thermal inversions) • An inversion trapped pollutants for 5 days from: • Steel mill, zinc smelter, sulfuric acid plant • Results: 7,000 of 14,000 inhabitants fell ill, 20 died
Question • Why has the incidence of smog moved from winter to summer?
Photochemical Smog NASA October 2000
Air PollutionPhotochemical Smog NOx + VOCs → O3
Ozone Production is Like Baking a Cake:Requires Time Hotter the day More O3 and other secondary pollutants produced Trafic inc. in the morning Levels of NOx and unburned hydrocarbons rise Produce more smog On a sunny day the photochemical smog builds up to peak levels early afternoon, irritating eyes and respiratory tracts
Air PollutionGround Level O3 Formation • The same O3 molecules that protect us from UV in the stratosphere • High O3 concentrations makes breathing difficult, especially for people with asthma and other respiratory diseases
Air PollutionOther Smog Types • Industrial Smog • Sulfur dioxide • Sulfuric acid dropets • Particulates • Sulfur compounds in coal an oil react with oxygen to form sulfur dioxide: S + O2 SO2
Air PollutionFactors Affecting Severity • Weather and topography, population, industry, types of fuel used • Hills, valleys and buildings restrict air flow and allow pollutants to build up at ground level • Concentration levels: • Higher emission rate, higher the concentration • Higher the wind speed the lower the concentration • Lower the inversion height the higher the concentration
Question Why do we have exceedences of CO in the winter evenings? Why do we have exceedences of PM in the winter evenings? Why do we have exceedences of O3 during summertime downwind of source regions? Calm winds, temperature inversion Wood burning fireplaces major source Calm winds, temperature inversion Sunshine, higher temperatures
SmogTemperature Inversions Troposphere usually well mixed (warm air rises, replaced by cooler air) Cool air trapped below warm air prevents mixing Inversion increases with calm winds
Demo • Inversion Chamber movie • Explain how the inversion chamber models an atmospheric thermal inversion
Air PollutionDaily Variation • Early morning traffic increases emissions of both NOx and VOCs as people drive to work • Later in the morning, traffic dies down and the NO and VOC’s react forming NO2 • As sunlight becomes more intense O3 forms faster • As the sun sets, the production of O3 is halted
Smog City • Smog city http://www.smogcity.com
Air PollutionState of the Air CNN 2003
Movies – Acid Rain FHS – Acid Rain HORIZON: A Killing Rain Acid rain was one aspect of environmental pollution high on the green agenda of the 1980s. Looking at the evidence from northern europe, this programme examines the background to the spread and recognition of this deadly environmental poison. 50 minutes. 1982. Acid Rain: New Bad NewsThe debate over acid rain continues to grow. NOVA travels to West Germany, the mid-Atlantic states and New England to examine the controversy surrounding this phenomenon.Original broadcast date: 12/11/84 Topic: environment/ecology
Acid Deposition Results from technological fix of one problem (local air pollution) What was the fix?
Acid DepositionCross-boundary Pollution • A large portion of SO2 and NO2 produced in one country is exported to others by prevailing surface winds • More than half the acid deposition in heavily populated southern Canada originates from seven central and upper midwestern states – OH, IN, PA, IL, MO, WV, and TN http://nadp.sws.uiuc.edu
Acid DepositionWhat is an acid? Sour taste, litmus test, reaction with carbonate Acid Rain Normal rainwater is weakly acidic (5.7) due to dissolved CO2
Acid Deposition Wet Deposition Removal of gases and particles by rain, snow, sleet, or fog Dry Deposition Removal of gases and particles in the absence of precipitation http://nadp.sws.uiuc.edu The National Atmospheric Deposition Program (NADP) monitors wet atmospheric deposition at 250 National Trends Network sites throughout the United States. The USGS supports 74 of the roughly 250 active NADP/NTN sites. A fundamental NADP program objective is to provide scientific investigators world-wide with a long-term, high-quality database of atmospheric deposition for research support in the areas of air quality, water quality, agricultural effects, forest productivity, materials effects, ecosystem studies, watershed studies and human health.
EPA Acid Deposition (Wet and Dry) Sulfur oxide (SOx) and nitrogen oxides (NOx) are not acids! + water + sunlight → Sulfuric acid and nitric acid
SOx Sulfur dioxide emissions are highest in regions with many coal-fired electric power plants, steel mills, and other heavy industries that rely on coal. Allegheny County, in western Pennsylvania, is just such an area, and in 1990 it led the United States in atmospheric SO2 concentration. SOx and NOx NOx The highest NOx emissions are generally found in states with large urban areas, high population density, and heavy automobile traffic. Therefore, it is not surprising that the highest levels of atmospheric NO2 are measured over Los Angeles County, the car capital of the country.
Acid DepositionEffects on Ecosystems • Acidification of surface water (lakes, rivers, etc), and subsequent damage to aquatic ecosystems. – kills aquatic plants, fish and microorganisms in lakes and streams by releasing ions of Al, Pb, Hg and Cd from soils and sediments. • Damage to forests and vegetation – Weakens or kills trees, especially conifers at high elevations; – Makes trees more susceptible to diseases, insects, drought, and fungi and mosses that thrive under acidic conditions; – Stunts growth of crops such as tomatoes, soybeans, spinach, carrots, broccoli and cotton
Acid DepositionEffects on Ecosystems • Kills aquatic plants, fish and microorganisms in lakes and streams by releasing ions of Al, Pb, Hg and Cd from soils and sediments. In acidified lakes the number of fish and amphibians is declining due to reactions of aluminum ions with proteins in the gills of fish and the embryo's of frogs High aluminum concentrations do not only cause effects upon fish, but also upon birds and other animals that consume contaminated fish
Neutralization of Soil by Acid Rain In North America most of the acidity comes from the burning of high sulfur content coal in power plants The effect of acid rain on biological life depends upon the composition of soil and bedrock in the Area – Acid Neutralizing Capacity (ANC) or buffering capacity Regions of North America with low soil alkalinity
Effects on Trees and Soils • Nutrient leaching • Heavy metal release • Weakens trees
Acid DepositionEffects on Humans • Respiratory diseases • Toxic metal leaching • Damage to structures (limestone, marble) • Damage to vehicles (rusting) • Decreases visability • Decreases productivity of fisheries, forests and farms
Acid DepositionSolutions 1980 National Acid Precipitation Assessment program 1990 CAA Ammendments 2000 Phase II CAA Decreases in SO2 but increases in NOx
Acid DepositionNY Lakes CNN 2001