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23 Cards in this Set
- Front
- Back
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which pollutants covered by national ambient air quality standards?
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CO, SO2, NO2, Pb, PM10, PM2.5, O3
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2 categories of ntnl ambient air quality stds
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primary-protect public health
secondary-protect public welfare (visibility, bdgs) "attainment" areas have met NAAQS, "non-attainment" areas have not |
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Clean Air Act Amendments of 1970
-name 4 important things included in this act |
-creation of NAAQS
-Congressional control (and not EPA control) of auto emissions with a required 90% reduction of HC, CO, NOx by mid-70's -new source performance standards (NSPS) for stationary sources -Ntnl Emission Stds for Hazardous Air Pollutants (NESHAPS) |
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catalytic converter: which pollutants it affect
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NOx → N2
unburned HC → H2O + CO2 CO→ CO2 created because the CAA 1970 required emissions of these 3 pollutants to be reduced |
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indoor air pollution sources:
Carbon Dioxide (CO2) |
breathing (people and animals), combustion
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indoor air pollution sources:
Carbon Monoxide (CO) |
combustion/vehicle emissions (stoves, fireplaces, heaters, cigarettes, in-garage cars)
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indoor air pollution sources:
Nitrogen Dioxide (NO2) |
infiltration, combustion (in-garage cars, kerosene and gas space heaters, wood stoves, gas stoves, cigarettes)
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indoor air pollution sources:
Ozone |
infiltration of outdoor air, photocopy machines, electrostatics air cleaners → higher concentration outdoors b/c need sun
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indoor air pollution sources:
Formaldehyde (HCHO) |
particleboard, insulation, paneling, plywood, carpets, tile → higher concentration indoors (need to ventilate to dilute)
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indoor air pollution sources:
Sulfur Dioxide (SO2) |
combustion of kerosene in space heaters, gas stoves, infiltration from outdoor combustion (mainly coal combustion) → higher concentration outdoors
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indoor air pollution sources:
Radon |
(two precursors and two products) – uranium (Ur) → radium (Ra) → radon (Rn) → lead (Pb) and polonium (Po) (see Fig. 9.1 for more details on radioactive decay process)
• Ur and Ra (Rn precursors) are bound in minerals, Rn is a gas, and Pb and Po are electrically charged and can be inhaled or attached to particles and inhaled (carcinogenic) • Need to ventilate crawl space to reduce risk of exposure |
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indoor air pollution sources:
Asbestos |
insulation (for pipes, boilers, etc), flooring materials, paint, wallpaper, fire-retardant materials → only a problem if stirred up, higher concentration indoors
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health effects from asbestos
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o Lung cancer
o Mesothelioma – cancer of the mesothelial membrane lining the lungs o Asbestosis – slow, debilitating disease of the lungs – scarring of lung tissue |
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indoor vs outdoor standards
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o Indoor standards are higher in general (that is, can pollute more indoors) b/c standards are designed to protect workers, who are assumed to be healthy adults (can withstand higher exposure), while outdoor standards protect ALL people (young, old, weak, sick, etc.)
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indoor vs outdoor standards for CO
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higher than for outdoor b/c designed for workers, also has indoor ceiling value b/c of harmful health effects past this concentration
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indoor vs outdoor standards of NO2
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additionally, stringent outdoor standard b/c precursor to photochemical smog, but indoor standards do not need to be based on NO2 being a smog-precursor (no sun), so indoor standards are based only on health concerns
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What acid was first noticed as dangerous to health and agriculture?
What technology and regulation were implemented to remove this acid from emissions? |
o HCl (Hydrochloric acid)
o Technology: scrubber o Regulation: 1863 Alkali Act (See section 10.1 for the details) • Remove 95% of HCl emissions from alkali factories • Response to scrubber technology → inexpensive and efficient method of removing hydrochloric acid from alkali factory emissions |
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gas-phase oxidation for converting S(IV) to S(VI)
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1) SO2 oxidize in gas phase to H2SO4
2) H2SO4 and water (attracted by H2SO4) condense onto aerosol particles or cloud drop to produce H2SO4-H2O aqueous solution 3) H2SO4 dissociates into 2H+ + SO42- ***oxidation in first step |
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aqueouc-phase oxidation for converting S(IV) to S(VI)
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1) Dissolution of SO2(g) into liquid water drops to produce SO2(aq)
2) SO2(aq) reacts with water in the drop to form H2SO3 (sulfurous acid) 3) H2SO3 dissociates into SO32- + 2H+ 4) HSO3- and SO32- oxidize to SO42- (precursor depends on pH) **oxidation in last step |
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o Lakes (neutralizing agents)
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• Ca(OH)2(aq) + 2H+ → Ca2+ + 2H2O(aq) slaked lime (also could use NaOH(aq))
• NH4OH(aq) + H+ → NH4+ + H2O(aq) ammonium hydroxide |
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o Soil (buffer)
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• CaCO3(s) + 2H+ → Ca2+ + CO2(g) + H2O(aq) calcite or calcium carbonate
• Like eqn 5.7 |
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o Areas near the coast (buffer)
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• NaCl(s) + H+ → HCl(g) + Na+ natural sea spray
• Like eqn 5.5 |
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• What is the effect of acid deposition on marble and limestone buildings?
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o Gypsum (CaSO4-2H2O ) crust forms on calcite surface → over time rain removes crust and leaves pits → soot from smoke deposits into pits and darkens buildings
H2SO4(aq) → 2H+ + SO42- CaCO3(s) + 2H+ → Ca2+ + CO2 + H2O(aq) Ca2+ + SO42- + 2H2O(aq) → CaSO4-2H2O(s) H2SO4(aq) + CaCO3(s) + H2O(aq) → CaSO4-2H2O(s) + CO2(g) overall process |
