 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

 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

 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

 Particulate Material  Nitrogen Oxides  Sulfur Oxides  Carbon Oxides  VOCs  Ozone

 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)

 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

› 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

 Carbon Oxides › carbon monoxide (CO)  Binds with hemoglobin  less oxygen  Incomplete combustion › carbon dioxide (CO 2 )  Greenhouse gas  global warming (global climate change)

 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!".

 Mercury › Bioaccumulation/biomagnification › Major source: burning coal (electricity) › Harm: brain damage (neurotoxin)  Lead › Gasoline › Paints – eaten by small children › Harm: brain damage (neurotoxin)

 Two main sources › Transportation › Industry  Natural – lightening caused fires; volcanoes

 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.

 NOx + VOCs + sunlight  photochemical smog (includes ozone)

 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

 Beijing (left)  Mexico City (above)  How tied to tourism/economics?

 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

 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

 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

 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

 Low level exposure › Irritates eyes › Causes inflammation of respiratory tract  Can develop into chronic respiratory diseases

 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

 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

 Most preventable cause of death › Lung cancer, heart attacks, strokes, other cancers  Increasing in China, Brazil, Pakistan; decreasing in US, Europe

 Smokestacks with electrostatic precipitator (right) Without Electrostatic precipitator With Electrostatic precipitator

 Smokestacks with scrubbers

 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

 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

 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

 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

 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

 More time inside  Better sealed/insulated for energy efficiency  More products from plastics and other petroleum-based products

Most serious indoor air pollutant From radioactive decay of uranium in Earth’s crust Increase lung cancer risks -2 nd leading cause

 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

 Cap and trade  Tax incentives for pollution control  Legislative standards for energy efficiency  Increasing research into renewable energy

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

 Ozone protects earth from UV radiation (UV-B, UV-C) › Part of the electromagnetic spectrum with wavelengths just shorter than visible light

 O2 + O  O3 (catalyzed by UV of sun)

 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

 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 >ClO+O 2 › ClO+O >O 2 +Cl

 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

 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