1. Ch. 18 Air Pollution

2. Air Pollution
Solids, liquids and gases present in atmosphere in high enough levels to harm humans, organisms, or materials

3. Layers of the Atmosphere
Atmospheric pressure (millibars)
Layers of the Atmosphere
200
400
600
800
1,000
120 75
Temperature
110 65
100
Layers characterized by changes in temperature which impact absorption rates of incoming solar radiation.
Thermosphere 90 55 80
Mesosphere 45 70
Altitude (kilometers)
Altitude (miles) 60 35 50
Stratosphere 40 25
Figure 18.3: Natural capital.
The earth’s atmosphere is a dynamic system that includes four layers. The average temperature of the atmosphere varies with altitude (red line) and with differences in the absorption of incoming solar energy. Note how the atmosphere’s temperature falls and rises again twice as we move from lower to upper layers. Because the troposphere receives most of its heat from the earth’s surface, it cools as its air gets further from the surface. Most ultraviolet radiation from the sun is absorbed by ozone, found primarily in the stratosphere’s ozone layer, 17–26 kilometers (11–16 miles) above sea level. This ozone absorption causes the temperature to rise in the stratosphere. Question: Why do you think most of the planet’s air is in the troposphere? 30 15
Ozone layer 20 10
Troposphere 5
Pressure
(Sea level)
–80
–40 80
120
Temperature (˚C)
Fig. 18-3, p. 467

4. Troposphere
Where weather occurs
“air” collects photochemical ozone

5. Stratosphere Contains O3 concentrations Referred to as ozone layer
Ozone acts as UV filter

6. Altitude (kilometers) Ozone concentration (ppm)40 25 35 20
Stratosphere 30
Watch This
Benefical Ozone 25
Stratospheric ozone 15
Altitude (kilometers) 20
Altitude (miles) 10 15 10 5
Troposphere
Harmful Ozone 5
Photochemical ozone 5 10 15 20
Ozone concentration (ppm)

7. Air Pollution Natural Sources Human-made sources Lightning Volcanoes
Wildfires
Dust blown by wind
Alter chem. of atm.
Concentrated in urban

8. Air Pollution Primary Pollutants Secondary Pollutants CO CO2 NO2 SO2
CH4 and most
other hydrocarbons
HNO3
H2SO4
Most suspended particles
H2O2 O3
PANs
Most NO3– and SO42– salts
Natural Source
Stationary
Human Source
Human Source
Mobile
Fig. 18-5, p. 469

9. Pollutants Primary Pollutants Secondary Pollutants
Emitted directly into the air
Carbon oxides, NOx, SO2, particulate matter, hydrocarbons
From reactions between primary pollutants and normal air components or other pollutants
Ozone, SO3
Air quality improving in developed countries
Less-developed countries face big problems
Indoor pollution: big threat to the poor

10. Pollutants

11. Major Classes of Air Pollutants
Carbon Oxides
Carbon monoxide & carbon dioxide
Sulfur Oxides
Sulfur dioxide & sulfur trioxide
Nitrogen Oxides
Nitric oxide, nitrogen dioxide, nitrous oxide
Volatile Organic Compounds (VOCs)
- Methane, propane, CFCs
Photochemical Oxidants
ozone, peroxycal nitrates (PAN), hydrogen peroxide (H2O2)
Suspended particulate matter (SPM)
Dust, soot, asbestos, lead, nitrate, and sulfate salts
Sulfuric acid, PCBs, dioxins, pesticides
Radioactive Substances
Radon-222, iodine-131, Strontium-90, plutonium-239
Hazardous Air Pollutants (HAPS)

12. Major Classes of Air Pollutants

13. Carbon Oxides Description Example Effect CO and CO2 CO ~ poisonous
CO2 – colorless & odorless
CO Carbon Monoxide
CO2 Carbon Dioxide
(93% = natural)
Greenhouse Gas
Global Warming
Reduces bloods ability to transport oxygen

14. Sulfur Oxides Description Example Effect
Gases produced as S + O combine at high temps
SO2 Sulfur Oxide
SO3 Sulfur trioxide
H2SO4 Sulfuric Acid
Acid rain
Respiratory health problems

15. Nitrogen Oxides Description Example Effect
Gases produced as N + O combine at high temps
Nitrogen cycle
NO Nitric Acid
NO2 Nitrogen Dioxide (NO combine with oxygen in air)
N2O Nitrous Oxide (GHG)
HNO3 Nitric acid
Inhibits plant growth
Health problems
Creates smog
Creates acid rain
Greenhouse gas
Global warming

16. Volatile Organic Compounds
Description
Example
Effect
Organic compounds that exist as gases in the atmosphere or that evaporate from sources on earth
Hydrocarbons from leaves
Methane CH4
Benzene or other liduids used as industrial solvents or dry cleaning fluids, etc.
Greenhouse gas
Global warming
Methane 20X more effective at warming atmosphere compared to CO2

17. Photochemical Oxidants OZONE O3
Description
Example
Effect
GOOD = stratospheric, protects from radiation
BAD = tropospheric,
Pollutant, light + NOx + VOCs = O3
O2 + UV = O3
Ozone hole results when strat. ozone react with CFCs to produce O2
Reduces visibility
Smog
Health problems
Greenhouse gas
Global warming

18. Suspended Particulate Matter
Description
Example
Effect
Solid/liquid particles suspended in atm
Soil, soot, lead asbestos
Reduce visibility
Corrodes Metals
Erodes buildings
Indoor air SPM = cigarettes, burning wood, charcoal, dung, and coal

19. Air Toxics Description Example Effect
other chemicals that react with other substances to create pollutants
Lead
Chlorine
HCl Acid
Fluorides
Radioactive substances
Long-term health effects

20. Effects of Air Pollution
Respiratory Health
Reduced Visibility
Corrodes Material
Reduces Crop Productivity
Acid Rain
Global Climate Change
Stratospheric Ozone Depletion
Health effects worse for children

21. Premature Deaths from Air Pollution in the U.S.
Figure 18.22: This map shows the distribution of premature deaths from air pollution in the United States, mostly from very small, fine, and ultra-fine particles added to the atmosphere by coal-burning power plants. Questions: Why do the highest death rates occur in the eastern half of the United States? If you live in the United States, what is the risk at your home or where you go to school? (Data from U.S. Environmental Protection Agency)
Fig , p. 485

22. Lead Pollutant found in air, water, soil, plants & animals.
Does not break down
Indestructible and potent neurotoxin harms nervous system

23. Chemical Reactions

24. China and Smog
Oct. 21, 2013