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CHE 264 Air Chem Qz1
Important information about atmospheric gases
Compound | Concentration | Source | Atmospheric Lifetime | Atmospheric Location | Sinks | Concern |
---|---|---|---|---|---|---|
Isoprene | 0.1-2 ppbv | Forests, Vehicle emissions | 2 hours | Troposphere | Oxidation | Greenhouse gas, Increases tropospheric O3 |
PAN | Urban: 50-250 ppbv Rural: <5 ppbv | CxHy+NOx | 3-10 days | Troposphere and Stratosphere | Thermal decomposition | Toxic, reservoir for NOx |
Benzene | 370 µg/m3 | Vehicle emissions, industrry | 12 days | Troposphere | Oxidation by OH | Carcinogen |
NOx | Urban: 100-400 ppbv Rural: <5 ppbv | Combustion, Supersonic aircraft, Lightning, Biomass burning, Soils | 1 day | Troposphere and Stratosphere | Formation of N2O5/HNO3 reservoirs | Urban pollution, Ozone depletion, Acid deposition |
ClONO2 | 0.1-1.6 ppbv | ClO+NO2+M -> ClONO2+M | 4 days | Troposphere and Stratosphere | Decomposition on PSCs | Reservoir for Cland NOx |
CH4 | 1.7 ppmv | Vehicle emissions, Biomass burning, Animals, Landfills, Gas (hydrofracking), Termites, Wetlands | 12 years | Troposphere and Stratosphere | Dissociation by Cl radical | Greenhouse gas |
SO2 | 10 ppt-1 ppb | Volcanic emissions, Photochemical, Anthropogenic | 1 day | Troposphere | Deposition, Oxidation by OH | Smog, Acid deposition, Impairs visibility |
CFC-12 | 500 pptv | Industry | 100 years | Troposphere and Stratosphere | Photodissociation in Stratosphere | Greenhouse gas, Stratospheric ozone depletion |
H2S | 0.05-0.3 ppbv | Swamps, photochemical | 1-2 days | Troposphere | Oxidation by OH | Acid deposition |
N2O | 319 ppbv | Agriculture emissions, Dentrification | 120 years | Troposphere and Stratosphere | Photodissociation | Greenhouse Gas, Ozone depletion |
O3 | Trop: 10-500 ppbv Strat: 0.5-10 ppmv Urban: 50-150 ppbv Rural: <5 ppbv | Photochemical | Hours-days | Troposphere and Stratosphere | Photodissociation, Reaction with HOx, NOx, ClOx | Urban Pollution, acid deposition, greenhouse gas, toxic to humans and vegetation |
CO2 | 360 ppmv | Combustion, Ocean | 100 years | Troposphere and Stratosphere | Photosynthesis | Greenhouse gas |
CO | Urban: 10,000-30,000 ppbv Rural: <200 ppbv | Combustion/Industry, Oxidation, Biomass burning, Oceans, Vegetation | 1 year | Troposphere and Stratosphere | Oxidation by OH, Soil Uptake | Toxic, Urban Pollution |