Download Chapter 18: Air Pollution South Asian Brown Clouds • Covers much

Chapter 18: Air Pollution
South Asian Brown Clouds
 Covers much of India, Bangladesh, Southern China, & open ocean just east
 Size of U.S.; 2 miles thick (1-3 mi. up)
 Made of…
o 1/3rd = dust, smoke, ash from drought & deforestation (for cropland)
o 2/3rd = soot, toxic metals (Pb, Hg), fly ash, organics from fossil fuels
 Cloud Effects
o Photosynthesis down 7-10% in China & India
o Acids in haze fall = damage crops & lakes
o 700,000 premature deaths per year from respiratory ailments
o Travels east to Japan, Korea, U.S.
 25% PM, 77% soot, 33% HG in LA
London’s Killer Smog
 December 1952 – thick smog settled on London
o 4 days = 4-12,000 dead
 Factory pollution + Thermal inversion
 Clean Air Acts (‘56 & ‘68) = Today – 90% less airborne particles
China
 16 of 20 most air-polluted cities
 Acid rain falls on 1/3 of China
 1-2 rank in CO2 emissions
Earth’s Atmosphere
 Thin layer of gases
o Absorbs solar radiation
o Burns up meteors
o Moderates climate
o Transports & recycles water & chemicals
 Atmospheric Properties
o Density
 Most dense near sea level
 Gravity pulls gas towards surface
o Atmospheric Pressure
 Greatest at low elevations due to more gas molecules overhead
 ‘Thin’ air at mountain peaks
 Troposphere
o Ground to 5-11 miles up
o N2 (78%) O2 (21%), Ar (1%), varying H2O , CO2, & traces
o Temp. decreases w/ altitude
o Has 75-80% of gases
o Weather & climate
o Tropopause is the ceiling
 Stratosphere
o 7-31 miles up
o Same gas ratios except…
 More ozone (blocks UV) –formed via O2 + UV radiation = O3
 Less water vapor
o Temp increases w/ altitude due to UV absorption
 Mesosphere
o 31-56 miles up
o Temp decreases w/ altitude (-130 = top)
 Thermosphere (Ionosphere)
o 51-300 miles up
o Temp increases w/ altitude (2730 = top)
o Very thin air; mostly lightweight elements
Outdoor Air Pollution
 Natural Sources
o Wind-blown dust, volcanoes, wildfires, volatile organic chemicals (VOC) from plants
 Anthropogenic (human) Sources
o Burning of fossil fuels
o Waste incineration
 Pollutant Types
o Primary Pollutant
 Emitted directly into air from source
 SO2, CO2, CH4, CFC, NOx
o Secondary Pollutant
 Formed after primary pollutants react w/ other stuff in atmosphere
 Photochemical smog, acid rain, tropospheric ozone, PANs
 Carbon Monoxide (CO)
o Colorless, odorless, very toxic gas
o Forms from incomplete combustion of carbon-containing materials
 Cars, burning of forest/grassland, tobacco, open fires
o Binds hemoglobin blocking O2 delivery
 Carbon Dioxide (CO2)
o Colorless & odorless gas
o 93% from natural carbon cycle
o Human activities – Burning of fossil fuels, forests, & grasslands
o Amplifies greenhouse effect
 Nitrogen Oxides (NOx)
o Nitric Oxide (NO)
 Colorless gas made by N2 & O2 at high temps (car, coal, lightning)
o Nitrogen Dioxide (NO2)
 Reddish-brown gas formed by NO & O2
o Reacts to form nitric acid (HNO3)
o Irritate eyes, nose, throat, lungs, & slow plant growth (photosynthesis)
 Sulfur Dioxide (SO2)
o Colorless gas w/ bad smell
o 1/3rd from sulfur cycle, rest from humans (coal, oil refining, smelting)
o Reacts to form sulfuric acid (H2SO4)
o Reduces visibility, aggravates breathing, damages soil, plants, water, buildings, metals
 Suspended Particulate Matter
o Variety of very small solid or liquid droplets light enough to stay in air
o 62% natural – dust, wild fires, sea salts
o Human – coal, industrial plants, cars, plowed fields, dirt roads, tobacco
o Fine (PM10) or ultra-fine (PM2.5)
 Harm lungs, reduce visibility, corrode metal, fade clothes & paints
 Very toxic = Pb, Cd, PCBs
 Lead (Pb)
o Element = can’t be degraded
o Former gasoline & paint additive
 Illegal in U.S. since 1970
 Old paint, pipes, buildings, red lipstick
o Very strong neurotoxin
 Kids – blindness, paralysis, low IQ, antisocial, behavior disorders
 Ozone (O3)
o Colorless & highly reactive gas
 Good in stratosphere, BAD in troposphere (secondary pollutant)
o Causes coughing, breathing problems, aggravate lung/heart disease, irritate eyes, nose, throat &
reduce immune function
o Damages plants, rubber, fabric, paints
o Major part of photochemical smog
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Volatile Organic Compounds
o aka VOCs; gaseous organic compounds
o Mostly hydrocarbons
 Isoprene & terpene (from plant leaves)
 Methane (CH4) – GHG; human-source
 Benzene, vinyl chloride, formaldehyde
o Lead to smog & secondary pollutants
o Benzene – leukemia, other blood disorders, immune damage, death
Industrial Smog (aka Gray Air Smog)
 Caused by burning coal
o Carbon = CO, CO2, & soot (solid C)
o Sulfur = SO2, H2SO4, ammonium sulfate [gray color; (NH4)2SO4]
o Mercury
 Improved (developed nation) – filters, boilers, scrubbers, smokestacks
Photochemical Smog (aka Brown Air Smog)
 Cars (gasoline) release NO & VOCs during morning traffic
 UV + gases = 100 compounds
o O3 (most), HNO3, NO2 (brown)
o PANs (peroxyacyl nitrates) – irritate eyes, lungs, ~skin cancer
 Life Cycle
o Gases released in morning drive
o Secondary pollutants (O3, PANs, etc.) peak at noon w/ sun
o Drop off during afternoon & evening
o Falling back to ‘0’ over night
Smog Dissipation
 Settling of particles (gravity)
 Rain & snow
 Spray from oceans
 Winds mix & dilute
 Chemical reactions (SO2 to H2SO4)
Smog Intensifying
 Hills/mountains reduce air flow, pollutants buildup
 High temps
 VOC emissions from plants (e.g. poplar, kudzu, some oaks)
 Grasshopper effect – volatile air pollutants transported to poles
 Temperature Inversion
o Warm air layer sits atop cooler air
o Resists mixing (cool air trap)
o Pollutants build up in stagnant air
o Most risky cities…
 Valley surrounded by mountains (Donora, PA)
 Cars, sunny, light wind, ocean on one side & mountains on rest (L.A.)
Heat Island Effect
 Cities are warmer than nature
o Urban buildings slow wind
 Less mixing of pollutants
 Less cooling temps
o Building materials absorb heat
o Cars, power plants, factories produce heat
Acid Deposition (pH <5.6)
 SO2 & NOx added to air forming HNO3 & H2SO4 (Last 2-14 days)
 Falls as…
o Dry deposition – acidic particles land on ground (e.g. SO2 & NOx)
o Wet deposition – snow, rain, fog
 Asia (China) has it worst
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Effects
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o
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Regional problem – smokestacks release pollution high in air (mixing)
Damage buildings, metals, cars
Release soil metals (Al, Pb, & Hg)
Leaches soil nutrients (hurts plants)
 Basic soils can buffer effects
o Acidifies surface water
o Human respiratory ailments
 Reduce N & S emissions
Indoor Air Pollution
 Poor have it the worst
 Developing Nations
o Particulates from burning coal, wood, crop residue, charcoal, plastics, garbage, dung
o Few workplace regulations = high risk for workers
 Developed Nations
o Indoor much worse than outdoor
o EPA…
 11 common pollutants 2-5x higher indoors
 Inside cars 18x worse
 70-98% time spent indoors or in car (magnifies effect)
 Top of list for cancer sources
 Human’s Natural Defenses
o Nose hair, cilia motion, mucus, sneeze, cough
 Types of Indoor Pollution
o Pb & pesticides stick to shoes
o Bacteria, virus, pollen, mold, dust mites, mildew
o Asbestos
o Sick-Building syndrome – illnesses caused by various factors
 Usually linked to poor air quality
 EPA’s 4 Worst
o Tobacco smoke
o Formaldehyde
o Radon-222 gas
o Very small particulates
 Formaldehyde
o U.S. – 20-40 mil. affected by it
 Breathing, skin, eyes, throat, sinus
o Wood in buildings, furniture, drapes, upholstery, adhesives, insulation, fingernail hardener,
wrinkle-free coating for clothes
o 1 in 5,000 get cancer; 10 yrs in manufactured home (H. Katrina)
 Radon-222
o Radioactive, colorless, odorless gas
o From underground rock
 Uranium-238 decay product
o Seeps up through ground
 Outdoors – disperses quickly & decays to low levels
 Indoors – builds up; decays to Po, Pb, Bi; Lung Cancer
o Seal Cracks & Add Ventilation
U.S. Clean Air Act
 Regulates emissions
o Sets national ambient air quality standards (NAAQS) for 6 criteria pollutants
 CO, NOX, SO2, O3, Pb, particulate matter (>PM10)
o Primary standard – for human health
o Secondary standard – for environment
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Standards for 188 hazardous air pollutants (HAPs)
o Cause serious health & eco effects
o Mostly chlorinated hydrocarbons, VOCs, toxic metals
o Toxic Release Inventory (TRI)
 21,500 refineries, mines, power plant, chemical maker release waste management records
for 667 toxins
Emissions Trading (aka Cap-and-Trade)
o 110 most polluting power plants buy & sell SO2 pollution rights
 Under Clean Air Act amendment
o Each yr, given credits allowing them to release certain SO2 amounts
 If under allotted credits, free to sell, expand plant, use at other plants
Improvement Needed?
o Prevention, not cleanup
o Raise fuel-efficiency standards
o Raise penalties
o More Cap & Trade
o Regulate…
 Old factories (20,000 not under law )
 2-stroke engines – boat, jet ski, dirt bike
 Airports & Oceangoing ships
 GHG emissions, Ultrafine particles, & O3