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Published byDarlene McCormick Modified over 9 years ago
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Atmosphere as a Resource Types and Sources of Air Pollution › Major Classes of Air Pollutants › Sources of Outdoor Air Pollutants › Urban Air Pollution Effects of Air Pollution Controlling Air Pollution in the US
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Atmospheric Composition › Nitrogen 78.08% › Oxygen 20.95% › Argon 0.93% › Carbon dioxide 0.04% Ecosystem services › absorbs UV radiation › Moderates the climate › Redistributes water in the hydrologic cycle
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Air Pollution › natural events or human activities in high enough concentrations to be harmful Two categories › Primary Air Pollutant emitted directly into the atmosphere › Secondary Air Pollutant formed in the atmosphere when a primary air pollutant reacts with substances normally found in the atmosphere or with other air pollutants
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Particulate Material Nitrogen Oxides Sulfur Oxides Carbon Oxides VOCs Ozone
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Solid or liquid particles suspended in air (soil particles, soot, lead, asbestos, and sulfuric acid droplets) › Combustion of wood, manure, coal, oil gasoline. Agriculture. Road construction.(Black soot from diesel engines more than gasoline powered vehicles) Natural sources: volcano/forest fires Scatter/absorb sunlight (large forest fire/volcanic eruption) reduced photosynthesis Dangerous for 2 reasons › May contain materials with toxic or carcinogenic effects › Extremely small particles (PM 10 and PM 2.5 ) can become lodged in lungs (reduce lung function)
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Nitrogen Oxides › Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at high temperature; cars! › Problems Greenhouse gas, ozone depleter, contributes to photochemical smog, leads to acid rain Respiratory irritant, slow plant growth
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› Gases produced by the chemical interactions between sulfur and oxygen; industry (chemicals, metal, paper)/power plants ( coal!!!!) › Causes acid precipitation › Respiratory irritant › Slow plant growth
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Carbon Oxides › carbon monoxide (CO) Binds with hemoglobin less oxygen Incomplete combustion › carbon dioxide (CO 2 ) Greenhouse gas global warming (global climate change)
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Tropospheric Ozone (BAD) › Secondary air pollutant (NOx + VOCs + sunlight) › Component of photochemical smog › Reduces lung function; asthma; reduce plant growth; degrade plastics/rubber Stratospheric Ozone (GOOD; not air pollutant) › Essential component that screens out UV radiation in the upper atmosphere › Man- made pollutants (ex: CFCs) can destroy it "Good up high, bad nearby!".
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Mercury › Bioaccumulation/biomagnification › Major source: burning coal (electricity) › Harm: brain damage (neurotoxin) Lead › Gasoline › Paints – eaten by small children › Harm: brain damage (neurotoxin)
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Two main sources › Transportation › Industry Natural – lightening caused fires; volcanoes
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Photochemical Smog (ex: Los Angeles below) › Brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and VOCs City surrounded by mountains; in a valley.
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NOx + VOCs + sunlight photochemical smog (includes ozone)
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NO + VOCs + O2 + uv O3 + PANs › NO2 + H2O 2HNO3 + NO › NO2 + VOCs PANs › NO2 + uv NO + O; O2 + O O3 PANs = peroxacyl nitrates Worse during the day b/c sun needed = duh! Hotter = more VOCs
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Beijing (left) Mexico City (above) How tied to tourism/economics?
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Industrial smog – “gray” smog Photochemical smog – worse in summer Temperature inversion (thermal inversion) › Cold air with pollutants trapped by warmer air above Valleys, coastal Urban heat island – localized heat buildup (concrete absorbs heat, tall buildings block wind, less vegetation, more industries/cars/air conditioners that produce heat increase thunderstorms; dust domes
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Issues: persistent compounds found in areas not using them: worse in colder regions (higher latitudes and higher elevations) › Ex: PCBs: stored in body fat, example of biomagnification Stockholm Convention on Persistent Organic Pollutants
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Sulfur dioxide and nitrogen dioxide emissions react with water vapor in the atmosphere and form acids that return to the surface as either dry or wet deposition pH scale: 1 number = 10x change NORMAL RAIN = pH 5-6 ACID RAIN = BELOW 5
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Adirondack Lakes, NY: no fish (reduces species diversity) Thin-shelled eggs prevent bird reproduction › Because calcium is unavailable in acidic soil Forest decline – increases nutrient leaching/directly harms leaves › Ex: Black forest in Germany (50% is destroyed) Erodes statues, buildings, etc
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Low level exposure › Irritates eyes › Causes inflammation of respiratory tract Can develop into chronic respiratory diseases
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Sulfur Dioxide and Particulate material › Irritate respiratory tract and impair ability of lungs to exchange gases Nitrogen Dioxides › Causes airway restriction Carbon monoxide › Binds with iron in blood hemoglobin › Causes headache, fatigue, drowsiness, death (at prolonged exposure) Ozone › Causes burning eyes, coughing, and chest discomfort, asthma
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Greater health threat to children than adults › Air pollution can restrict lung development › Children breath more often than adults Children who live in high ozone (O 3 ) areas are more likely to develop asthma
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Most preventable cause of death › Lung cancer, heart attacks, strokes, other cancers Increasing in China, Brazil, Pakistan; decreasing in US, Europe
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Smokestacks with electrostatic precipitator (right) Without Electrostatic precipitator With Electrostatic precipitator
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Smokestacks with scrubbers
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Catalytic converters: reduce CO, NOx, and VOCs Drive less › Mass transit › Bike lanes/wide sidewalks › Carpooling/lanes Hybrid vehicles Restrict evaporation of dry-cleaning fluid Reduce # of wood burning stoves
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EPA sets limits on amount of specific air pollutants permitted Focuses on 6 pollutants: › lead, particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides, and ozone (CO 2 added in 2007) Act has led to decreases! Clean Air Act Amendment of 1990 focused on reducing acid rain
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Reduce sulfur content in gasoline from its current average of 330 ppm to 30 ppm › Sulfur clogs catalytic converters Require federal emission standards for all passenger vehicles › Including SUVs, trucks and minivans Require emission testing for all vehicles › Including diesel
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Air quality is deteriorating rapidly in developing countries Shenyang, China › Residents only see sunlight a few weeks each year Developing countries have older cars › Still use leaded gasoline 5 worst cities in world › Beijing, China; Mexico City, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India
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Worse in developing countries – wood/manure/coal indoors pneumonia/bronchitis Most common: › Radon, cigarette smoke, carbon monoxide, nitrogen dioxide, formaldehyde (carpets) pesticides, lead (paint/plumbing), cleaning solvents, ozone (photocopiers), and asbestos
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More time inside Better sealed/insulated for energy efficiency More products from plastics and other petroleum-based products
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Most serious indoor air pollutant From radioactive decay of uranium in Earth’s crust Increase lung cancer risks -2 nd leading cause
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Highly sealed buildings build-up of VOCs and other toxic material (glues, cleaning agents, copy machines), mold/pollen….poor ventilation Eyes irritated, headaches, nausea, respiratory infections › Lost work time, medical bills
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Cap and trade Tax incentives for pollution control Legislative standards for energy efficiency Increasing research into renewable energy
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Possible solutions: noise barriers next to highways, limit vehicle speed, quieter jet engines, local laws/enforcement for residential power tools, loud radios, etc. Unit of measurement: decibel (db) Prolonged exposure damages hearing by hurting hair cells in the cochlea Increases heart rate, migraines, dizziness, stress Disrupts animal behavior: frogs calls difficulty finding a mate
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Ozone protects earth from UV radiation (UV-B, UV-C) › Part of the electromagnetic spectrum with wavelengths just shorter than visible light
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O2 + O O3 (catalyzed by UV of sun)
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Ozone thinning/hole › First identified in 1985 over Antarctica Caused by › human-produced bromine and chlorine containing chemicals › Ex: CFCs (chlorofluorocarbons): propellants, coolants, foam-blowing agents › Stable: stay in atmosphere
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Thinning over Antarctica requires two conditions: (between Sept. and Nov. – spring) › Sunlight just returning to polar region › Circumpolar vortex- a mass of cold air that circulates around the southern polar region Isolates it from the warmer air in the rest of the planet causes clouds that Cl and Br stick Polar stratospheric clouds form › Enables Cl and Br to destroy ozone › Cl+O 3 ------------->ClO+O 2 › ClO+O------------->O 2 +Cl
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Higher levels of UV- radiation hitting the earth › Eye cataracts › Sunburns, Skin cancer (right) › Weakened immunity decrease photosynthesis damage crops (reduce crop yields) and forests
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Montreal Protocol Montreal Protocol (1987) › Reduction of CFCs (also a greenhouse gas) by 50% originally › Started using HCFCs (Hydrochlorofluorocarbons; weaker ozone depleter;greenhouse gas), phasing out Phase out of all ozone destroying chemicals is underway globally ozone layer is recovering; full recovery will not occur until ~ 2050
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