Rebekah Campbell
AP Environmental Science Class
December 9, 2010
Chapter 18: Air Pollution
I.
Atmosphere a.
Layers i.
Troposphere:
1.
closest to earth. System involved in chemical cycling of earth’s nutrients. ii.
Stratosphere: 17-48 kilometers abover earth’s surface. a.
Ozone layer: “global sunscreen” protects from sunburn eye and skin cancer cataracts etc. b.
INFLUENCED BY GRAVITY i.
DENSITY
1.
MOLECULES PER LITER
2.
DECREASES WITH ALTITUDE ii.
ATMOSPHERIC PRESSURE
1.
FORCE PER UNIT AREA
2.
DECREASES WITH ALTITUDE c.
PROVIDES i.
PLANETS WEATHER AND CLIMATE ii.
CHEMICAL CYCLING OF VITAL NUTRIENTS iii.
GLOBAL SHIELD FROM INCOMING SOLAR RADIATION
IV.
Major Outdoor Air Pollution Problems a.
Pollution comes from natural and human sources i.
Natural sources: dust in wind/volcanic eruptions/chemicals from plants ii.
Human sources: people/cars/factories/burning of fossil fuels b.
Two categories of Pollutants i.
Primary: harmful chemicals emitted directly into the air from natural processes and human activities. ii.
Secondary: some primary pollutants react with one another and air and form new harmful chemicals. c.
Good news: the quality of outdoor in most developed countries over the past 30 years has improved. d.
Bad news: WHO declares that more than 1.1 billion people live in urban areas where outdoor air is unhealthy to breathe.
1.
Indoor air pollution: caused by burning of wood/coal in fires. e.
Major outdoor pollutants i.
Carbon oxides
1.
Carbon monixide: highly toxic gas that forms during the incomplete combustion of carbon-containing materials (motor vehicle exhaust/forest burning/tobacco smoke)

2.
Carbon dioxide: 93% of atmosphere in the result of carbon cycle.
Comes from human activites/burning fossil fuels/clearing CO2 absorbing forests and grasslands. ii.
Nitrogen oxides and nitric acid
1.
Nitric oxide: forms when nitrogen and oxygen gas react at high combustion temperatures in cars and coal burning plants. iii.
Sulfur dioxide and sulfuric acid
1.
Sulfur dioxide: comes from natural sources as part of sulfur cycle iv.
Particulates
1.
Suspended particulate matter (SPM): variety of particles floating in air. Comes from natural sources such as dust/wild fires/sea salt. v.
Ozone: major component of photochemical smog. vi.
Volatile organic compounds: hydrocarbons emitted by leaves of plants and methane. Human sources: rice paddies/landfills/oil wells. f.
Burning coal produces industrial smog i.
Industrial smog: consists of sulfur dioxide/suspended droplets of sulfuric acid/variety of suspended solid particles. ii.
INDUSTRIAL SMOKESTACKS REDUCE LOCAL POLLUTION BUT CAN INCREASE
REGIONAL AIR POLLUTION DOWN WIND iii.
Remains a problem in urban areas: China/India/Ukraine – where large quantities of coal are still burned in houses/power plants/factories. g.
Sunlight plus cars equals photochemical smog i.
Photochemical smog: a mixture of primary and secondary pollutants formed under the influence of UV radiation from the sun. ii.
Begins when exhaust from morning commuter vehicles release large amounts of NO and VOCS into the air over the city. NO is converted to NO2. Some is reacted with VOCS by certain trees. Result = mixture of ozone/nitric acid/aldehydes/peroxyacyl nitrates/and other secondary pollutants. h.
Several factors can decreases or increase outdoor air pollution i.
5 natural factors can reduce
1.
particles heavier than air settle out as a result of gravitational attration to earth.
2.
Rain and snow help cleanse the air
3.
Salty sea spray from the oceans wash pollutants out from air
4.
Winds sweep pollutants away by mixing them w/ cleaner air
5.
Some pollutants are removed from chemical reactions ii.
6 factors can increase
1.
urban bulidings can slow wind speed – reduce removal
2.
hills and mountains can reduce flow of air
3.
high temps promote chemicals reactions leading to photochemical smog
4.
emissions of VOCS from certain trees/plants make photochemical smog

5.
grasshopper effect: volatile air pollutants are transported by evaporation and tropical winds through the atmosphere to the earth’s polar areas – where they are deposited. Occurs during winter.
6.
Temperature inversions a.
LAYER OF WARM AIR TEMPORARILY ON TOP OF A LAYER OF
COOLER AIR b.
COOL AIR CAN’T RISE AND BECOMES STAGNANT c.
can cause pollutants to build to high levels
V.
Acid Deposition a.
Acid deposition is a serious regional air pollution problem i.
Acid deposition: acid rain ii.
CAUSED BY EXCESSIVE AMOUNTS OF NITROGEN OXIDES AND SULFUR DIOXIDE
TO THE ATMOSPHERE iii.
Coal burning plants emit air pollutants and these remain in the atmosphere for 2-14 days (either in wet deposition or dry deposition) iv.
Typical precipitation in the eastern US is at least 10X more acidic than natural precipitation is. v.
Worst acid deposition occurs in Asia – in China – where 70% of total energy and 80% of its electrictiy is from burning coal. vi.
Harms aquatic ecosystems. Most fish can’t survive in water with less pH than
4.5 vii.
Harms crops and affects forests by leaching essential plant nutrients. viii.
Most of the world’s forests and lakes are not being destrpyed or seriously harmed by acid deposition. b.
We know how to reduce acid deposition i.
Reduce coal use ii.
Burn low-sulfur coal iii.
Increases natural gas use iv.
Increase use of renewable energy resources v.
Remose SO2 particulates and NOX from smokestack gases vi.
Tax emissions of SO2 vii.
Reduce air pollution by improving energy efficiency c.
REDUCTION IS POLITICALLY DIFFICULT i.
PEOPLE AFFECTED DISTANT FROM THOSE WHO CAUSE IT ii.
COUNTRIES WITH LARE COAL SUPPOOLIES WANT TO USE IT AS MAJOR
ENERGY SOURCE iii.
There is still a long way to go even though the US has made air pollution laws.
1.
ONE OF THE FIRST AND STILL MOST IMPORTANT LAWS PASSED BY
THE UNITED STATES TO ADDRESS AIR POLLUTION WAS THE CLEAN AIR
ACT OF 1956
VI.
Indoor Air Pollution Problems a.
Indoor air pollution is a serious problem i.
LEVELS OF MANY POLLUTANTS ARE OFTEN HIGHER INSIDE A CAR OR
BUILDING THAN THEY ARE OUTSIDE ii.
Especially an issue for poor people

1.
Indoor burning of wood/charcoal/coal/and other cooking and heating fluids in open fires exposes people to dangerous levels of particulate air pollution. iii.
ALSO A PROBLEM IN DEVELOPED COUNTRIES
1.
examples of pollutants indoors a.
dust mites and cockroach droppings b.
airborne spores of mold and mildew c.
tobacco smoke and radioactive radon-222 gas d.
formaldehyde – found in buildings/furnitire/drapes/carpeting/wallpaper
VII.
Health Effects of Air Pollution a.
Your body’s natural defenses against air pollution can be overwhemed i.
Your respiratory system is equipped with mechanisms to protect you from harmful air pollution. ii.
Long exposure to air pollutants- like tobacco smoke – can overload or break down these natural defenses. b.
Air pollution is a big killer i.
According to WHO – at least 3 million people worldwide die prematurely each year from the effects of air pollution – 8200 deaths per day. ii.
In the US – 150000 to 350000 people die annually from indoor and outdoor air pollution. iii.
EPA has proposed stricter emission standards for disel-powered vehicles.
VIII.
How Should We Deal with Air Pollution? a.
Laws and Regulations can reduce outdoor air pollution. i.
Clean Air Acts in 1970/1977/1990 ii.
Congress directed EPA to extablish national ambient air quality standards for
6 outdoor criteria pollutants – carbon monixide/nitrogen oxides/sulfur dioxide/suspended particulate matter/and lead. iii.
Low sulfur diesel fuel iv.
Environmental scientists point to areas where the model could stand improvement. b.
Case Study: US Air Pollution Laws can be Improved c.
We Can Use the Marketplace to Reduce Outdoor Air Pollution i.
Clean Air Act of 1990 – authorizes an emissions trading or cap – and –trade program which enables the 110 most polluting power plants in 21 states to buy and sell SO2 pollution rights. ii.
Ultimate success of any emissions trading approach depends on how low the intial cap is set and then on the lwoewring of the cap every few years. d.
There are many ways to reduce outdoor air pollution i.
Prevention
1.
Use mass transit
2.
Walk or bike
3.
Use less polluting fuels
4.
Improve fuel efficiency
5.
Get older cars off the road

6.
Give large tax writeoffs or rebates for buying low-polluting energy effiecient vehicles. e.
Reducing indoor air pollution should be a priority i.
Prevention
1.
Clean ceiling tiles and AC ducts
2.
Ban smoking or limit it
3.
Set stricter formaldahyde emissions standards forcarpe/furniture/and building materials
4.
Prevent radon infiltration
5.
Use office machines in well ventilated areas
6.
Use less pollutiung substitutes for harmful cleaning agents/paints/and other products. f.
We need to put more emphasis on pollution prevention i.
Use output approaches ii.
Shift to preventing air pollution iii.
“What can we do about the air pollutants we produce?”