ch 19 acid rain acid rain outdoor/ indoor pollution
TRANSCRIPT
Factors Influencing Levels of Outdoor Air Pollution
• Outdoor air pollution can be reduced by:– settling out, precipitation, sea spray, winds, and
chemical reactions.
• Outdoor air pollution can be increased by:– urban buildings (slow wind dispersal of pollutants),
mountains (promote temperature inversions), and high temperatures (promote photochemical reactions).
Temperature Inversions
• Cold, cloudy weather in a valley surrounded by mountains can trap air pollutants (left).
• Areas with sunny climate, light winds, mountains on three sides and an ocean on the other (right) are susceptible to inversions.
Figure 19-5Figure 19-5
Fig. 19-5, p. 447
Warmer air Descending warm air mass
Inversion layer Inversion layer
Sea breezeIncreasing altitude
Decreasing temperature
PLAYVIDEO
ACID DEPOSITION
• Sulfur dioxides, nitrogen oxides, and particulates can react in the atmosphere to produce acidic chemicals that can travel long distances before returning to the earth’s surface.– Tall smokestacks reduce local air pollution but can
increase regional air pollution.
ACID DEPOSITION
• Acid deposition consists of rain, snow, dust, or gas with a pH lower than 5.6.
Figure 19-6Figure 19-6
Fig. 19-6, p. 448
WindTransformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas and
particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts
Wet acid depostion (droplets of H2SO4 and HNO3 dissolved in rain and snow)Nitric oxide (NO)
Sulfur dioxide (SO2) and NO
Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts)
Acid fogFarm
OceanLakes in deep soil Lakes in deep soil high in limestone high in limestone
are bufferedare buffered
Lakes in shallow soil Lakes in shallow soil low in limestone low in limestone
become acidicbecome acidic
ACID DEPOSITION
• pH measurements in relation to major coal-burning and industrial plants.
Figure 19-7Figure 19-7
ACID DEPOSITION
• Acid deposition contributes to chronic respiratory disease and can leach toxic metals (such as lead and mercury) from soils and rocks into acidic lakes used as sources for drinking water.
ACID DEPOSITION• Air pollution is
one of several interacting stresses that can damage, weaken, or kill trees and pollute surface and groundwater.
Figure 19-9Figure 19-9
Fig. 19-9, p. 451
Emissions
SO2 NOxAcid deposition
H2O2 O3
Others
Direct damage to leaves & bark
Reduced photo-synthesis and growth
Susceptibility to drought, extreme cold, insects, mosses, & disease organisms
Soil acidification Tree death
Leaching of soil nutrients
Release of toxic metal ions
Root damage
Reduced nutrient & water uptakeAcids
Lake
Groundwater
PANs
Fig. 19-10, p. 452
SolutionsAcid Deposition
Prevention Cleanup
Reduce air pollution by improving energy efficiency
Add lime to neutralize acidified lakes
Reduce coal use
Add phosphate fertilizer to neutralize acidified lakes
Increase natural gas use
Increase use of renewable energy resources
Burn low-sulfur coal
Remove SO2 particulates & NOx from smokestack gases
Remove NOx from motor vehicular exhaust
Tax emissions of SO2
INDOOR AIR POLLUTION• Indoor air pollution usually is a greater threat to
human health than outdoor air pollution.• According to the EPA, the four most dangerous
indoor air pollutants in developed countries are:– Tobacco smoke.– Formaldehyde.– Radioactive radon-222 gas.– Very small fine and ultrafine particles.
Chloroform
Benzo--pyrene
Styrene
Radon-222
Methylene Chloride
Tobacco Smoke
Carbon Monoxide
Asbestos
Nitrogen Oxides
1, 1, 1-Trichloroethane
Particulates
FormaldehydeTetrachloroethylene
Para-dichlorobenzene
Fig. 19-11, p. 453
INDOOR AIR POLLUTION• Household dust mites that
feed on human skin and dust, live in materials such as bedding and furniture fabrics.– Can cause asthma attacks
and allergic reactions in some people.
Figure 19-12Figure 19-12
PLAYVIDEO
Case Study: Radioactive Radon
• Radon-222, a radioactive gas found in some soils and rocks, can seep into some houses and increase the risk of lung cancer.
Sources and paths of entry Sources and paths of entry for indoor radon-222 gasfor indoor radon-222 gas.
Figure 19-13Figure 19-13
Fig. 19-13, p. 454
Outlet vents for furnaces and dryers
Open window
Openings around pipes
Cracks in wall
Slab joints
Wood stove
Cracks in floorClothes dryer
Sump Sump pumppumpFurnace
Slab Radon-222 gas Uranium-238
Soil
HEALTH EFFECTS OF AIR POLLUTION
• Your respiratory system can help protect you from air pollution, but some air pollutants can overcome these defenses. Figure 19-14Figure 19-14
Fig. 19-14, p. 455
Epithelial cellCilia
Nasal cavity
Oral cavity
Goblet cell (secreting mucus)
Pharynx (throat)
MucusTrachea (windpipe)
BronchusBronchioles
Right lung
Bronchioles
Alveolar sac (sectioned)
Alveoli
Alveolar duct
PLAYVIDEO
HEALTH EFFECTS OF AIR POLLUTION
Normal human lungs (left) and the lungs of a person who died of emphysema (right).
Figure 19-15Figure 19-15
Air Pollution is a Big Killer
• Each year, air pollution prematurely kills about 3 million people, mostly from indoor air pollution in developing countries.– In the U.S., the EPA estimates that annual deaths
related to indoor and outdoor air pollution range from 150,000 to 350,000.
– According to the EPA, each year more than 125,000 Americans get cancer from breathing diesel fumes.
Air Pollution is a Big Killer
• Spatial distribution of premature deaths from air pollution in the United States.
Figure 19-16Figure 19-16