1. AIR POLLUTION Composition of Air:
Mixture composed of 78% Nitrogen (N2), 21% Oxygen (O2), 0.06% Carbon Dioxide (CO2)
Also contains water vapor, gaseous pollutants, and solid particles (particulates)
Air Pollution – a change to the atmosphere that has harmful effects
Types of Air Pollution
Smog
Acid Rain
Global Warming
Destruction of the Ozone Layer
Indoor Air Pollution

2. AIR POLLUTION Smog – combination of smoke and fog
Photochemical Smog – thick, brownish haze when certain gases in the air react with sunlight
Gases mainly come from cars and trucks
Gases form ozone – a toxic gas
Temperature Inversion – a layer of warm air prevents the pollution (smog) from rising above the city
Problems include:
Itchy, watery eyes
Scratchy throat
Lung problems
Harms the body’s defense against illness

3. AIR POLLUTION
Acid Rain - a condition that arises when certain gases in the atmosphere react with rain water, turning it acidic
Nitrous and Sulfer Oxides + water  nitric acid and sulfuric acid
Gas pollutants come from car engines (nitrous oxide) and coal burning plants (sulfer oxides)
Lowers pH of rain water below its normal value
pH – a scale that measures the acidity of solutions
Acid – below 7; Neutral – 7; Base – above 7 (14 is highest)
Unpolluted rain water is 5.2 (slightly acidic)  acid rain is when the pH falls well below that level
Damages environment
Can kill large areas of forests
Releases heavy metals out of the soil
Makes waterways unsuitable for aquatic life
Can destroy certain materials in buildings and statues

4. AIR POLLUTION
Ozone Depletion – harmful pollutants reacting with a layer of our atmosphere known as the ozone layer, causing it to decrease
Ozone Layer – a layer of the atmosphere that contains a small amount of ozone (O3) gas
About 30 km above surface
Helps protect against ultraviolet radiation from sun  UV rays cause sunburn and skin cancer
Ozone absorbs UV energy; keeps it from getting to surface
Ozone is recycled (see Figure 6, P. 145)
Chlorofluorocarbons (CFC’s) – molecules that react with ozone, stopping it from being recycled
Come from air conditioners, refrigerators, fire extinguishers, aerosol cans
Now CFC’s are banned in most countries
Large hole over Antarctica and Australia

5. AIR POLLUTION
Global Warming – the idea that certain pollutants in the atmosphere are causing the temperature of the Earth to rise too quickly
Greenhouse effect – certain compounds trap the heat entering the Earth’s atmosphere; prevents it from reflecting back into space
Greenhouse gas – gases that cause the greenhouse effect
Carbon dioxide is most common greenhouse gas
Works like a car window on a hot summer day  heat can get in, just can’t get back out
Natural and needed  the Earth’s temperature would be way too cold without this effect
Some scientist worry that too many greenhouse gases are accumulating in our atmosphere
Carbon dioxide is on the increase
Burning of fossil fuels
Deforestation
Other greenhouse gases include water vapor, methane, and certain nitrogen and sulfur compounds
Potential Consequences
Dramatic changes in climate
Coastal flooding – melting of polar ice caps
Mass extinction – weather changing faster than organisms can adapt
NOT ALL SCIENTISTS AGREE THAT GLOBAL WARMING IS HAPPENING!

6. AIR POLLUTION Indoor Air Pollution
Allergens such as pollen, dander, dust
Cigarette smoke
Asbestos – used to be used as an insulator
Associated with lung disease
Carcinogenic – linked to causing cancer
Has to be removed now in public buildings
Carbon Monoxide – CO
Description: Colorless odorless gas
Problem: Binds with blood cells that carry oxygen – keeps oxygen from getting to body cells
Source: when wood, coal, oil or gas are not burned completely
Can by detectors to warn if levels get too high
Radon
Description: colorless, odorless gas that is radioactive
Problem: can cause lung problems and cancers
Source: formed naturally by rocks underground; leaks in through cracks in basements
Can install ventilation units to keep Radon from building up

7. AIR POLLUTION Solutions: Emissions control CFC substitutes
Emissions – solid particles and gas that are released into the air
Laws set up to limit what factories can put into the air
Scrubber – using water to clean emissions before releasing into atmosphere
Catalytic converter – a device in cars and trucks that reduces emissions of carbon monoxide, hydrocarbons, nitrogen oxides
Forms less harmful carbon dioxide and water
CFC substitutes
General Conservation Practices
Reduse, reuse, recycle
Carpool, find alternative ways for transportation
Use less energy
Support agencies and organizations that are for protecting the environment