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APES > Unit 7 - Atmospheric Pollution > Flashcards

Unit 7 - Atmospheric Pollution Flashcards

1
Q

***Write about air pollutants (specific molecules or particles) not just air “pollution” as an idea

A
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2
Q

Clean Air Act

A

Clean Air Act (1970) identified 6 criteria air pollutants that EPA is required to set acceptable limits for, monitor, and enforce

  • SO2, NOx, CO, PM, O3, Pb
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3
Q

SO2 (sulfur dioxide)

A
  • formed from Coal combustion (electricity)
  • Respiratory irritant, smog, acid precipitation
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4
Q

NOx (nitrogen oxides)

A
  • formed from All FF combustion (gas esp.)
  • O3 | photochemical smog | acid precip.
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5
Q

CO

A
  • formed from incomplete combustion
  • O3, lethal to humans
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6
Q

PM (particulate matter)

A
  • FF / biomass combustion
  • respiratory irritant | smog
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7
Q

O3 (tropospheric ozone)

A
  • formed from the Photochemical oxidation of NO2
  • Respiratory irritant|smog|plant damage
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8
Q

Pb (lead)

A
  • formed from metal plants, waste incineration
  • Neurotoxicant
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9
Q

Air Pollutants vs Greenhouse Gases

A
  • CO2 is NOT one of the 6 criteria pollutants in the Clean Air Act
  • CO2 does not directly lower air quality from human standpoint (not toxic to breath, not damaging to ENT, does not lead to smog)
  • CO2 is a GREENHOUSE GAS, it leads to earth warming => env. and human health consequences
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10
Q

Coal Combustion

A
  • releases more air pollutants than other FF’s
  • 35% of global electricity
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11
Q

Impacts of SO2

A
  • respiratory irritant (inflammation of lungs), asthma, bronchitis
  • sulfur aerosols (suspended sulfate particles) block incoming sin, reducing visibility and photosynthesis
  • forms sulfurous smog
  • combines w water and O2 in atmosphere to form sulfuric acid => acid rain
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12
Q

EPA and Lead

A
  • Before CAA, lead was a common gasoline additive; EPA began phaseout of lead from gasoline in 1974
  • vehicles made post 1974 are required to have catalytic converters to reduce NOx and HC emissions (lead damages converters)
  • damages nervous system
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13
Q

primary air pollutants

A
  • emitted directly from sources such as vehicles, power plants, factories, or natural sources (volcanoes, forest fires)
  • NOx, CO, VOCs, SO2, PM, hydrocarbons
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14
Q

Secondary Air Pollutants

A
  • primary pollutants that have transformed in presence of sunlight, water, O2
  • occur more during the day (since sunlight often drives formation)
  • tropospheric O3
  • sulfuric acid (H2SO4) & sulfate (SO4-2)
  • nitric acid and nitrate ion
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15
Q

Photochemical Smog Precursors

A

~ NO2 - broken by sunlight into NO + O (free O + O2 => O3)

~ VOCs - Volatile Organic Compounds (Hydrocarbons) that bind with NO & form photochemical oxidants
- carbon based compounds that volatize (evaporate) easily (this make them smelly)
- sources: gasoline, formaldehyde, coniferous trees, oil based paints, cleaning fluids

~ O3 - forms when NO2 is broken by sunlight and free O binds to O2

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16
Q

Photochemical Smog Conditions

A
  • Sunlight: drives O3 formation by breaking down NO2 => NO + O; then free O binds with O2
  • Warmer: Hotter atmo. temp. speeds O3 formation, evaporation of VOCs and thus smog formation
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17
Q

factors that increase smog formation

A
  • more sunlight (summer, afternoon) = more O3
  • higher temp speeds evap. of VOC’s & rxn that leads to O3
  • high VOCs emissions (gas stations, laundromats, plastic factories)
  • higher vehicle traffic, higher NO2 emissions, and therefore O3 formation
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18
Q

impact of smog

A

environment - reduces sunlight; limiting photosynthesis
- O3 damages plant stomata and irritates animal resp. tracts

humans - resp. irritant; worsens asthma, bronchitis, COPD; irritates eyes

economic - high healthcare costs to treat asthma, bronchitis, COPD
- lost productivity due to sick workers missing work or dying
- ag. yields due to low sunlight reaching crops and damage to plant stomata

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19
Q

reduction of smog

A

Vehicles - decreasing the # of vehicles on the road lowers NO2 emissions
- decrease vehicles = low gas = low VOCs
(carpooling, public transport, biking, walking, etc.)

Energy - increased electricity production from renewable sources that don’t emit NOx (solar, wind, hydro)
- natural gas power plants release far less NOx than coal

20
Q

urban heat island effect

A

urban areas tend to have higher surface and air temperature than surrounding suburban and rural areas due to:

  • lower albedo; concrete and asphalt absorb more of sun’s energy than areas with more vegetation
  • less evapotranspiration: water evaporating from surfaces and transpiration from plants carries heat from surface into atmosphere and cools off rural and suburban areas w vegetation
21
Q

normal convection

A
  • normally, the atmosphere is warmest at earths surface and cools as altitude rises
  • because warm air rises, air convection carries air pollutants away from earth’s surface and distributes them higher into the atmosphere
22
Q

thermal inversion

A
  • because cold air at the surface is trapped beneath the warmer mass above, convection doesn’t carry pollutants up and away
  • during a thermal inversion, a cooler air mass becomes trapped near earth’s surface (inverting normal gradient)
    • due to a warm front moving in over it
    • due to hot urban surfaces cooling overnight while IR radiation absorbed during the day is still being released
23
Q

effects of thermal inversion

A
  • air pollutants (smog, PM, ozone, SO2, NOx) trapped closer to earth
  • respiratory irritant
  • decreased tourism revenue
  • decreased photosynthetic rate
24
Q

Natural Sources of Air Pollutants

A
  • Lightning Strikes (Convert N2 in atm. to NOx)
  • forest fires (CO, OM, NOx)
  • plants (esp. conifers) - emit VOC’s
  • volcanoes - SO2, PM, CO, NOx
25
Q

natural sources of CO2 & PM

A
  • respiration: all living things release CO2
  • aerobic decomp: decomp of organic matter by bacteria and decomposers in the presence of oxygen => releases CO2
  • anaerobic decomposition: decomp of organic matter by bacteria and decomposers in low or O2 free conditions => releases CH4
  • natural PM sources: sea salt, pollen, ash from forest fires, volcanic dust => leads to haze
26
Q

Particulate Matter

A

solid or liquid particles suspended in air (also referred to as “particulates”)

27
Q

PM10

A

particles or droplets like dust, pollen, ash, pr mold

  • too small to be filtered out by nose hairs and trachea cilia; can irritate respiratory tract & cause inflammation
28
Q

PM2.5

A
  • particles from combustion (esp. vehicles) smaller dust particles
  • more likely to travel deep into the lungs due to smaller size
  • associated with chronic bronchitis and increased risk of lung cancer
29
Q

Indoor Air Pollutants: developing nations

A
  • developing nations use more subsistence fuels such as wood, manure, charcoal (biomass)
  • these biomass fuels release CO, PM, NOx, VOCs
  • often combusted indoors with poor ventilation, leading to high concentrations
  • est. 3 billion people globally cook with subsistence fuels, resulting in est. 3.5 - 4.3 million deaths annually
30
Q

Indoor Air Pollutants: developed nations

A
  • developed nations use more commercial fuels (coal, oil, natural gas) supplied by utilities
  • typically burned in closed, well ventilated furnaces, stoves, etc
  • come from chemicals in products: adhesives in furniture, cleaning supplies, insulation, lead paint
31
Q

INDOOR AIR: PM and Asbestos

A
  • PM is a common indoor air pollutant
    ex: smoke (from indoor biomass combustion or cigarettes), dust, and asbestos
  • asbestos is a long, silicate particle previously used in insulation ( since been linked to lung cancer and asbestosis)
  • phased out of use, but still remains in older building
  • not dangerous until insulation is disturbed and asbestos particles enter air and then resp. tract
  • should be removed by trained professionals
32
Q

INDOOR AIR: CO

A
  • CO is produced by incomplete combustion of basically any fuel
  • CO is an asphyxiant = causes suffocation due to CO binding to hemoglobin
33
Q

how is CO released in developing nations

A

CO emitted from indoor biomass combustion for heating or cooking

34
Q

how is CO released in developed nations

A

CO released into home by malfunctioning natural gas furnace ventilation

35
Q

VOCs

A
  • chemicals used in variety of home products that easily vaporize, enter air, and irritate eyes, lungs, bronchioles
  • adhesives/sealants
  • formaldehyde
  • cleaners
  • plastics and fabrics
36
Q

Radon Gas

A
  • Radon 222 is a radioactive gas released by decay of uranium naturally found in rocks underground (granite especially)
  • usually enters homes through cracks in foundation
  • can also seep into groundwater sources and enter body through drinkning water
  • 2nd leading caused of lung cancer after smoking
  • EPA recommends testing homes with airborne Radon monitor
  • seal cracks in foundation to prevent entering
37
Q

reducing emission = reducing air pollutants

A
  • drive less, walk/bike/bus more
  • conserve electricity (smart appliances)
  • eat more plants, less meat
  • renewable, non-pollution emitting energy (solar, wind, hydro)
38
Q

clean air act

A
  • allows EPA to set acceptable levels for criteria air pollutants
  • monitor emissions levels from power plants and other facilities
  • tax/sue/fine corporations that release emissions above levels
39
Q

pollution credits

A
  • similar to ITQs for fish
  • companies that reduce emissions well below EPA-set levels earn pollution credits
  • they can sell these to companies that release more than acceptable levels
40
Q

CAFE Vehicle Standards

A
  • (Corporate Avg Fuel Economy) standards require the entire US “fleet” of vehicles to meet certain average fuel
  • requires vehicle manufacturers to work to make more efficient vehicles
  • more efficient vehicles burn less gasoline and release less NOx, PM, CO, CO2
41
Q

vapor recovery nozzle

A
  • capture hydrocarbon VOCs released from gasoline fumes during refueling
  • separate tube inside nozzle captures vapors and returns the, to underground storage tank beneath the gas station
  • reduces VOCs, which contribute to smog and irritate resp. tracts
  • also reduces benzene (carcinogen) released from gasoline vapors
42
Q

baghouse filter (PM)

A
  • large fabric bag filters that trap PM as air from combustion/industrial process passes through
  • shaker device knocks trapped particles loose into collection hopper below
    • PM collected and taken to landfill
43
Q

Catalytic Converter

A
  • required on all vehicles since 1975
  • contains metals that bind to NOx and CO
  • CC converts NOx, CO, and other hydrocarbons into CO2, N2, O2, & H2O
44
Q

crushed limestone (SO2)

A
  • used to reduce SO2 from coal power plants
  • crushed coal mixed with limestone before being burned in boiler
  • limestone combines with SO2 to produce calcium sulfate, reducing the SO2 being emitted
  • limestone can be used to make gypsum wallboard or sheetrock for home foundations
45
Q

fluidized bed combustion

A
  • fluidized jets of air pumped into combustion bed
  • jets of air bring more O2 into rxn, making combustion more efficient and bringing SO2 into more contact with limestone
  • also allows coal to be combusted at lower temp, which emits less NOx
46
Q

Wet and Dry Scrubbers

A

are air pollution control devices that remove particulates and/or gases from industrial
exhaust streams.

47
Q

urban noise pollution

A

any noise at great enough volume to cause physiological stress (difficulty communicating, headaches, confusion) or hearing loss

  • constructions
  • transportation
  • industrial activities
  • domestic activity

APES (6 decks)

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