Ch. 16 Flashcards
composition of the atmosphere (3)
- 78% nitrogen
- 21% oxygen
- 1% other (argon, CO2, methane, water vapor)
Layers of the atmosphere (4)
- troposphere
- air pollution issues
- stratosphere
- air pollution issues
- Ozone layer: protects from UV rays
- mesosphere
- thermosphere
define pollution
addition of matter or energy that degrades the environment
2 sources of pollutants
- natural
2. anthropogenic (human-produced)
dense population centers and pollutants (3)
- use large quantities of fossil fuels for manufacturing, transportation, and domestic activities
- release large quantities of pollutants
- high population density correlated with poor air quality
primary air pollutants
directly released from a source
what does primary air pollutants include (5)
- carbon monoxide (CO)
- volatile organic compounds (VOCs)
- particular matter (PM)
- sulfur dioxide (SO2)
- oxides of nitrogen (NOx)
secondary air pollutants
results from interaction of primary air pollutants in presence of sunlight
what does secondary air pollutants include (4)
- Ozone (O3)
- particular matter (PM)
- oxides of nitrogen (NOx)
- peroxyacetyl nitrates (PAN)
How many pollutants has EPA established standards for?
6 “Criteria Pollutants”
6 “criteria pollutants”
- carbon monoxide (CO)
- particular matter (PM)
- sulfur dioxide (SO2)
- nitrogen dioxide (NO2)
- lead (PB)
- Ozone (O3)
hazardous air pollutants (HAPs or air toxics)
separate category of substances with higher toxicity (187 total HAPs)
examples of HAPs (6)
- benzene
- methyl chloride
- perchloroethylene
- asbestos
- mercury
- dioxin
Formation of carbon monoxide (CO)
formed from combustion of fossil fuels
impacts of CO (1)
binds to hemoglobin, reducing ability of blood to carry oxygen
current status of CO
70% reduction for 1990-2009
particular matter (PM)
solid particles and liquid drops dispersed into atmosphere
formation of PM10 (6)
- coarse particles
- dust from road travel
- agriculture
- construction
- industry
- smoke
formation of PM2.5 (2)
- fine particles
- secondary pollutants such as sulfates and nitrates
impacts of PM (2)
- reduced visibility
2. respiratory probs
Current status of PM10
38% reduction for 1990-2009
current status of PM2.5
27% reduction for 2000-2009
formation of sulfur dioxide (SO2) (2)
- formed from combustion of fossil fuels (coal)
- most SO2 generated by power plants
Impacts of SO2 (3)
- aggravates respiratory probs
- reacts with H2O and O2 to form acids
- can be inhaled or contribute to acid precipitation
current status of SO2
65% reduction for 1990-2009
formation of NO2 (2)
- nitrogen monoxide (NO) formed from combustion of fossil fuels
- NO is converted into NO2 in the atmosphere
impacts of NO2 (4)
- haze
- acid precipitation
- respiratory probs
- components of photochemical smog
current status of NO2
40% reduction for 1990-2009
formation of lead (PB) (2)
- lead additives to gas and paint
- metal smelters and battery manufacturers
impacts of PB (3)
many health impacts including:
- kidney damage - mental retardation
current status of PB (2)
- lead has been removed from gas and paints
2. 99.5% reduction in atmospheric lead concentration
volatile organic compounds (VOCs)
hydrocarbons that evaporate easily
formation of VOCs
formed from combustion of fossil fuels and use of solvents
impacts of VOCs (2)
- contrib to formation of photochemical smog
2. some are hazardous air pollutants
current status of VOCs
43% reduction from 1990-2009
Ground-level Ozone (O3) and Photochemical Smog
“good up high, bad nearby”
O3
highly reactive secondary pollutant
Photochemical smog
- mixture of pollutants (O3, aldehydes, PAN) that result from interaction of NO2, NO, and VOCs in the presence of sunlight and warm temps
- fog and smoke
Impacts of O3 and photochemical smog (3)
- respiratory probs
- damages plants
- reduces agricultural yields
Current status of O3 and photochemical smog
21% reduction 1990-2009
where is photochemical smog most commonly found? (2)
- cities with lots of car traffic, lots of sunlight, and warm temps
- cities in valleys or close to mountain ranges (thermal inversions)
clean air act guidelines to controlling air pollution (6)
- establish air quality standards
- conduct periodic reviews of criteria pollutants
- reduce emissions of acid rain precursors (SO2, NOx)
- reduce emissions of pollutants which reduce visibility and generate haze
- control toxic air pollutants
- limit use of chemicals which damage stratospheric ozone layer
emission reductions that have improved air quality (3)
- motor vehicles
- particular matter
- power plants
acid deposition (3)
- accumulation of acid-forming particles on a surface
- wet deposition: rain, snow, fog
- dry deposition: dry particles
sources of acid deposition (3)
- natural and anthropogenic sources
- SO2 - sulfuric acid
- NOx - nitric acid
impacts of acid deposition on structures
limestone, wears away over time
impacts of acid deposition on terrestrial ecosystems
forest decline due to acidification of soils and presence of aluminum
impacts of acid deposition on aquatic ecosystems
reduction of species diversity due to acidic conditions and presence of aluminum
current status of acid deposition
reduction in SO2 and NOx emissions from motor vehicles and power plants have reduced acid precipitation
describe stratospheric ozone (2)
- absorbs 99% of UV energy from the sun
- UV light has high energy content and is linked to:
- skin cancer in humans
- increased mutations in all organisms
depletion of O3 (2)
- CFCs react with O3 in atmosphere and deplete O3 layer
- CFCs are highly stable
Current status of O3 (2)
- production and use of CFCs has decreased significantly
- size of O3 hole appears to be stabalizing
