density
molecules per liter
atmospheric pressure
is the force, or mass, per unit area of a column of air. is caused by the bombardment of a surface such as your skin by air molecules
troposphere
the atmospheric layer closest to the earth's surface. extends only about 17km above sea level at the equator and 8km over the poles.
stratosphere
extends from about 17-48km above the earth's surface. contains less matter than the troposhpere, its composition is similar, with 2 exceptions: its volume of water vapor is about 1/1000 that of the troposphere, and its concentration of ozone (O3) is much
oxone layer
is the small amount of ozone concentrated in the stratosphere, found roughly 17-30km above sea level. stratospheric ozone produced when some of the oxygen molecules there interact with UV radiation emitted by the sun. keeps about 95% of the sun's harmful
air pollution
is the presence of chemicals in the atmosphere is concentrations high enough to harm organisms, ecosystems, or human-made materials
primary pollutants
are harmful chemicals emitted directly into the air from natural processes and human activities.
secondary pollutants
when some primary pollutants react with each other and with the basic components of air
carbon oxides
is a major outdoor air pollutant. carbon monoxide is colorless, odorless, and is a highly toxic gas that forms during the incomplete combustion of carbon-containing materias. ex: motor vehicle exhaust, burning of forests and grasslands, tobacco smoke, and
nitrogen oxides and nitric acid
nitric oxide is a colorless gas that forms when nitrogen and oxygen gas in air react at the high-combustion temps in automobile engines and coal-burning plants. nitric acid is a component of harmful acid deposition. NO --> photochemical somg.
sulfur dioxide and sulferic acid
is a major outdoor pollutant. SO2 is a colorless gas with a irritating odor. 1/3 comes from natural sources as part of sulfur cycle. 2/3 from human sources (combustion of sulfur-containing coal in electric power and infustrial plants. H2SO4 reduce visibil
particulates
is a major outdoor pollutant. suspended particulate matter (SPM) consists of a variety of soild partivles and liquid droplets small and light enough to remain suspended in the air for long periods. 62% from natural sources, 38% from human sources (coal-bu
ozone
is a major outdoor pollutant. is a colorless and highly reactive gas and is a major component of photochemical smog. can cause coughing and breathing problems, aggracte heart and lung diserases, reduce resistance to colds and pneumonia, and irritate the e
volatile organic compouns (VOC)
is a major outdoor pollutant. are organic compouns that exist as gas in the atmosphere. most are hydrocmarbons (isoprene, terpenes, methane). 1/3 methan emissions from natural resources, mostly plants, wetlands, and termites. rest from human sources (rice
industriial smog
consists mostly of sulfure diozide, suspended dropets of sulferic acid, and a variety of suspended solid particles. when burned, most of carbon in coal and oil converted into CO and CO2. unburned carcon in coal ends up in atmosphere as sooy. when col and
acid deposition
sometimes called acid rain. most dry occurs 2-3 days near emission sources, most wet 4-14 days in more distant downwind areas.
stationary sources
power and industrial plants
mobile sources
motor vehicles
smog
deadly mixture of smoke and fog
indoor air pollutio
caused by burning of wood, charcoal, coal, or dung in open fires or poorly designed stoves to heat their dwellings and cook their food.
gray air smog
suspended particles of such salts and soot give the resulting smog a gray color
brown air smog
VOCs + NOx + heat + sunlight --> groundlevel ozone + other photochemical oxidants + aldehydes + other secondary pollutants. NO is converted to reddish brown NO2.
photochemical oxidants
NO2, O3, and PANs. damaging chemicals can react with and oxidize certain compounds in the atmosphere or inside your lungs.
5 natural factors to help reduce outdoor air pollution
1: particles heavier than aire settle out as a result of gravitational attraction to the earth. 2: rain and snow help cleanse the air of pollutants. 3: salty seaspray from the ocean washed out much of the particulates and other water-soluble pollutants fr
6 factors can increase outdoor air pollution
1: urban buildings (slow wind speeds and reduce dilution and removal of pollutants). 2: hills and mountains ca nreduce the flow of of air in valleys below them and allow pollutant levels to build up at ground level. 3: high temps promote the chemical reac
temperature inversion
S,of cooler air nearer ground. cuz cool air denser than warm air, air near surface not rise and mix with above air, allows pollutants to build up in stagnant layer of cool air near ground. towns or city located in valley surrounded by mountains. city with
wet deposition
acid rain, snow, fog, cloud vapor wuth pH less than 5.6*
dry deposition
acidic particles
deficiencies in US air pollution control laws
US rely mostly on pollution cleanup, rather than prevention; congress failed to increase fuel-efficiency standards for cars, SUVs, ans=d light trucks; regulation of emission from motorcycles and 2cycle gasoline engines remains inadequate; little or no reg
Clean Air Act of 1990
authorizes an emissions trading, or cap-and-trade, program. enables the 110 most polluting power plants in 21 states to buy and sell SO2 pollution rights.