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 effectsTypes of Air Pollution

SmogAcid RainGlobal WarmingDestruction of the Ozone LayerIndoor Air Pollution

Smog – combination of smoke and fogPhotochemical Smog – thick, brownish haze

when certain gases in the air react with sunlightGases 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 eyesScratchy throatLung problemsHarms the body’s defense against illness

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 acidGas 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 solutionsAcid – 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 forestsReleases heavy metals out of the soilMakes waterways unsuitable for aquatic lifeCan destroy certain materials in buildings and statues

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) gasAbout 30 km above surfaceHelps protect against ultraviolet radiation from sun

UV rays cause sunburn and skin cancerOzone 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 recycledCome from air conditioners, refrigerators, fire

extinguishers, aerosol cansNow CFC’s are banned in most countries

Large hole over Antarctica and Australia

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!

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

Solutions: Emissions control

Emissions – solid particles and gas that are released into the air

Laws set up to limit what factories can put into the airScrubber – using water to clean emissions before

releasing into atmosphereCatalytic 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, recycleCarpool, find alternative ways for transportationUse less energySupport agencies and organizations that are for

protecting the environment