2. The Atmosphere
•Mixture of gases that surround Earth
- Made up of layers
- Troposphere near surface
- Stratosphere highest
- Ozone layer between
- Absorbs harmful UV
•Natural Atmospheric Warming–
Greenhouse effect
- Atmosphere stores heat
- Greenhouse gases
- Water vapor
- CO2
- Methane
- Nitrous oxide
- Solar energy passes through atmosphere
- Changed and reflected back by troposphere
3. Natural Cycles on Earth
• Natural cycles essential for our
atmosphere:
– Carbon cycle
– Nitrogen cycle
– Sulfur cycle
• Can be altered by human activities
degrading the quality of the air we
breathe!
4. The Carbon Cycle
Carbon cycles through air, water, soil, and organisms
- CO2 gas is key
- 0.039% of atmosphere
- Increasing CO2, increasing temperature
- Fossil fuels
- Being burned at rapid rate
- Adding CO2 to atmosphere
- Increasing global temperature
5. The Nitrogen Cycle
Forms of N cycle in
air, water, soil
organisms
Addition of nitrogen
pollutants
Combustion fixes
some N in air
7. Why Should You Care About Air Pollution?
•Presence of chemicals at high levels in the air
–Affects human, organisms, ecosystems, or objects
•Caused by pollutants
–Natural
–Man-made
•Indoor and Outdoor
•Every year:
–2.4 million people die from illnesses related to air pollution
–1.5million of these are cause by indoor pollution
–In the US, 150,000-350,000 deaths/yr
9. 6 Major Air Pollutants (EPA)
Click the
image to find
out more
about the
EPA’s list of
“Common Air
Pollutants”
10. Primary and Secondary Air Pollutants
Primary air pollutants come from natural and human sources.
Secondary air pollutants form in the atmosphere.
11. What Are the Problems?
Indoor Air Pollution
• Kills more people than outdoor
• Greater problem in less-developed countries
• Open fires for heating and cooking
• Tobacco smoke
• Chemicals from manufacturing
• Radon gas
Health Effects of Indoor Air Pollution
12. Industrial Smog
Coal burnt in cities in past
- Industrial smog
- Sulfur dioxide
- Suspended particles
- Droplets of sulfuric acid
Conditions better in more-developed
areas
- Growing problem in developing
countries
- U.S. a model for reducing industrial
smog
Consider This:
China has 16 of the world’s
20 most polluted cities!
13. Photochemical Smog
Mixture of secondary pollutants
- VOC
- NO and NO2
- Ozone
- Cities with lots of motor vehicles
- Sunny, warm, dry climate
- Example: Los Angeles, CA
14. Acid Deposition
Acidic particles droplets falling from the air
- Sulfur dioxide
- Coal burning
- Motor vehicles
- Droplets of sulfuric acid
- Nitric acid vapor
- Particles of sulfate and nitrate
- Damages soil and structures
15. Climate Change
Earth’s atmosphere has been warming
- Very rapid recently
- Strong link to burning fossil fuels
- Glaciers shrinking in many places
- Sea ice reductions in arctic
- Many potential impacts
- Flooding
- Storm intensity
- Changes in ecosystems
16. What Can Be Done?
Two Ways to Deal with Air Pollution
1. Pollution cleanup
- Collecting and disposing of pollutants
- Very difficult
- Expensive and produces other wastes
2. Pollution prevention
- Use low pollution fuels
- Alternatives
- Solar cells, wind turbines
- Cut waste of energy
17. Reducing Indoor Air Pollution
Two largest threats
- Tobacco smoke
- Often banned in public places
- Education programs
- Indoor fires
- Replace leaky stoves
- Use no-combustion cooking
- Low-emission building materials
18. Reducing Outdoor Air Pollution
Variety of methods, most technological
- Low emission cars
- Reduce factory emissions
- Avoid producing emissions in first place
- Clear Air Act of 1970, 1977 and 1990
- Limits on six key pollutants
19. What Would You Do?
Reduce in-home
pollution
• make home as
energy-efficient
• no formaldehyde
• test for radon,
asbestos, pollutants
• high-efficiency
stoves
• insulation in home,
efficient lighting
Energy-efficient
transportation
• walking, biking, bus
or subway
• energy efficient
vehicles
• electric vehicles
Purchase of items
• eating less meat
• buy items that can
be reused or
recycled
• low packaging
• careful shopping to
avoid waste
