1. Chapter 12: Air 12-1 What Causes Air Pollution
Air Pollution: when harmful substances build up in the air to unhealthy levels (solids, liquids, gasses)
Most comes from human activities (vehicles and industry)
Primary Pollutants: a pollutant that is put directly into the air by human activity

2. Pollutant
Description
Primary Sources
Effects
Carbon Monoxide (CO)
Odorless, colorless
Cars, trucks, buses, small engines, some industrial processes
Interferes w/ blood’s ability to carry oxygen, slowing reflexes, causing drowsiness, can cause death
Nitrogen Oxides
Burning fuels in vehicles, power plants, industrial boilers
Can make body vulnerable to respiratory infections, lung diseases and cancer.
Contributes to brownish haze over cities and acid precipitation.
Sulfur Dioxide (SO2)
Burning fossil fuels
Acid precipitation
Reacts with other substances to form secondary pollutants that can harm plant life and irritate human respiratory system.
Volatile Organic Compounds (VOCs)
Chemicals that vaporize readily and form toxic fumes
Burning fuels (vehicles are a major source)
Contribute to smog formation.
Can cause serious health problems, cancer.
May harm plants
Particulate Matter (particulates)
Tiny particles of liquid or solid matter
Construction, agriculture, forestry, and fires.
Vehicles and industrial processes.
Can form clouds that reduce visibility and cause a variety of respiratory problems.
Linked to cancer.
May corrode metals and erode buildings and sculptures.

3. Secondary Pollutants: formed when a primary pollutant reacts with other primary pollutants or with naturally occurring substances (like water)
Ex. Ground-level Ozone = vehicle exhaust + UV rays + Oxygen

4. Motor Vehicle Emissions
The Clean Air Act (1970, strengthened in 1990)
EPA can regulate vehicle emissions in the U.S.
Gradually eliminated lead in gasoline (reduced lead pollution more than 90%!)
Catalytic Converters (required in vehicles) clean exhaust gases of pollutants before they leave the tailpipe
EPA estimates that cars and trucks have 95% fewer emissions than 30 yrs. Ago

5. California Zero-Emission Vehicle Program
In 1990 CA established a program to require 16% of all vehicles sold in CA to be zero-emissions vehicles (ZEVs) by 2016
No tailpipe emissions / No emissions from gasoline
Electric Vehicles were becoming increasing available, and charging stations were becoming more common in parking lots.
Who Killed the Electric Car?
Car Manufacturers and the Bush Administration sued CA in 2003.
The revised program has been severely watered down.
As a result, electric car production was virtually stopped.

6. Industrial Air Pollution
Clean Air Act - many industries must use scrubbers or other pollution-control devices.
Scrubber: machine that removes many pollutants from emissions by spraying gases with water.
Clear Skies Initiative – check it out
Smog: when air pollution hangs over urban areas and reduces visibility (vehicles & industry are main causes)
Sun +Air+Vehicle Exhaust+Ozone

7. Directing Traffic With a Smog Mask in Bangkok, Thailand

8. Temperature Inversions
Normal Conditions – air temp. decreases w/ height
Warm air near the surface (carrying pollution) is less dense and tends to rise until it finds air of the same temp/density
Usually carries pollution up & away

9. Temperature Inversions
Temperature Inversions – colder air near the surface with warmer air above
Cold air near the surface is warmer and more dense – so it resists rising
This “traps” pollutants near earth’s surface

10. Temperature Inversions – Why?
On a clear night, when the earth's surface radiates heat away rapidly.  If the air is clear, the ground, and the air directly above it, can be cooler than the air at higher altitudes.
Air blowing in from cold water to a coastal area.
At night in valleys, when cold, dense air flows downslope under the influence of gravity, draining off the slopes and uplands, and into the valleys.  The air in the valley bottoms is colder than the air above. 

11. 12-2 Air, Noise, and Light Pollution
Health Effects of Air Pollution
– children and elderly are particularly sensitive
Short-Term Health Effects of Air Pollution
Headache; nausea; irritation to eyes, nose, and throat; tightness in the chest; coughing; upper respiratory infections (bronchitis, pneumonia)
Long-Term Health Effects of Air Pollution
Emphysema, lung cancer, heart disease

12. Indoor Air Pollution
The air indoors may be more polluted than the air outside.
Major Sources of indoor air pollution: Plastics, cleaning chemicals, building materials
Sick-Building Syndrome: buildings that have very poor air quality
Common in hot places where building are tightly sealed to keep out the heat

13. Radon Gas Colorless, tasteless, odorless, and radioactive
Produced by decay of uranium (occurs naturally in Earth’s crust)
Seeps through cracks and holes in foundation into buildings
Adheres to dust particles  enters lungs
2nd leading cause of lung cancer in the U.S.

14. Asbestos Minerals that form in long, thin fibers
Strong and resistant to heat
Used mainly as insulation and fire retardant
Banned in U.S. in early 70’s
Inhaled  can cut and scar lungs  causes asbestosis
Difficulty breathing, maybe eventual death from heart failure
Billions spent to remove asbestos from schools

16. Noise Pollution Unnecessary sound of any kind.
Ex. airplanes, construction equipment, city traffic, factories, appliance, lawnmowers
Problems: loss of hearing, high blood pressure, stress, loss of sleepdecreased productivity
Decibels (dB): unit for measuring sound

17. Light Pollution
Inefficient lighting in urban areas diminishes our view of the night sky and wastes energy.
No direct hazard to human health
Ex. billboards lit from below, lighting of building exteriors, poor-quality street lights
Solutions: shield light so it is directed downward; timers, light or motion sensors (use light only when needed); using energy efficient lighting

19. 12-3 Acid Precipitation
Acid Precipitation: rain, sleet, snow that contains a high concentration of acids.
Sulfur oxides and nitrogen oxides (from burning fossil fuels) combine with water in the atmosphere to form sulfuric and nitric acids. Precipitation (rain, sleet, snow) that contains these acids is called acid precipitation.
SO2 + O2 = SO3 + H2O = H2SO4
NO + O2 = NO2+ H2O = HNO3

20. pH Pure Water = 7.0 Normal Precipitation = 5.6
Acid Precipitation <5.0
Eastern Europe
U.S

21. Acidification: increase in the concentration of acid
Causes Changes Soil Chemistry:
Some nutrients are dissolved and washed away
Aluminum and other toxic metals may be released and absorbed by plants
Aluminum causes root damage
Sulfur dioxide causes clogs the openings on the surfaces of plants

22. Acid Shock: when a sudden influx of acidic water enters a lake or stream and causes a rapid change in pH that harms aquatic life.
Causes large numbers of fish to die
Affects the reproduction of fish and amphibians

23. Acid Precipitation and Humans
Toxic metals (i.e. aluminum, mercury) can be released into the environment from the soilthen into crops, water, fishpoison the human body
May be linked to increased respiratory problems.
Negative for commercial & sport-fishing.
Forestry (trees damaged)
Can dissolve calcium carbonate in building materials like concrete, limestone, marble.

24. International Conflict and Cooperation
Pollutants released in one geographical area may fall to the ground hundreds of kilometers away as acid precipitation – sometimes in another country.
Canada-U.S. Air Quality Agreement: both countries agreed to reduce acidic emissions that flowed across the border.