Presentation on theme: "AIR POLLUTION Composition of Air:"— Presentation transcript:
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 effectsTypes of Air PollutionSmogAcid RainGlobal WarmingDestruction of the Ozone LayerIndoor Air Pollution
2 AIR POLLUTION Smog – combination of smoke and fog Photochemical Smog – thick, brownish haze when certain gases in the air react with sunlightGases mainly come from cars and trucksGases form ozone – a toxic gasTemperature Inversion – a layer of warm air prevents the pollution (smog) from rising above the cityProblems include:Itchy, watery eyesScratchy throatLung problemsHarms the body’s defense against illness
3 AIR POLLUTIONAcid Rain - a condition that arises when certain gases in the atmosphere react with rain water, turning it acidicNitrous 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 valuepH – 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 levelDamages environmentCan kill large areas of forestsReleases heavy metals out of the soilMakes waterways unsuitable for aquatic lifeCan destroy certain materials in buildings and statues
4 AIR POLLUTIONOzone Depletion – harmful pollutants reacting with a layer of our atmosphere known as the ozone layer, causing it to decreaseOzone 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 surfaceOzone 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 countriesLarge hole over Antarctica and Australia
5 AIR POLLUTIONGlobal Warming – the idea that certain pollutants in the atmosphere are causing the temperature of the Earth to rise too quicklyGreenhouse effect – certain compounds trap the heat entering the Earth’s atmosphere; prevents it from reflecting back into spaceGreenhouse gas – gases that cause the greenhouse effectCarbon dioxide is most common greenhouse gasWorks like a car window on a hot summer day heat can get in, just can’t get back outNatural and needed the Earth’s temperature would be way too cold without this effectSome scientist worry that too many greenhouse gases are accumulating in our atmosphereCarbon dioxide is on the increaseBurning of fossil fuelsDeforestationOther greenhouse gases include water vapor, methane, and certain nitrogen and sulfur compoundsPotential ConsequencesDramatic changes in climateCoastal flooding – melting of polar ice capsMass extinction – weather changing faster than organisms can adaptNOT ALL SCIENTISTS AGREE THAT GLOBAL WARMING IS HAPPENING!
6 AIR POLLUTION Indoor Air Pollution Allergens such as pollen, dander, dustCigarette smokeAsbestos – used to be used as an insulatorAssociated with lung diseaseCarcinogenic – linked to causing cancerHas to be removed now in public buildingsCarbon Monoxide – CODescription: Colorless odorless gasProblem: Binds with blood cells that carry oxygen – keeps oxygen from getting to body cellsSource: when wood, coal, oil or gas are not burned completelyCan by detectors to warn if levels get too highRadonDescription: colorless, odorless gas that is radioactiveProblem: can cause lung problems and cancersSource: formed naturally by rocks underground; leaks in through cracks in basementsCan 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 airLaws 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 oxidesForms less harmful carbon dioxide and waterCFC substitutesGeneral Conservation PracticesReduse, reuse, recycleCarpool, find alternative ways for transportationUse less energySupport agencies and organizations that are for protecting the environment