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POLLUTION Pollution is “change in background conc. ”. “Any substance introduced into the environment that adversely affects the usefulness of a resource”. Pollution happens because no process is 100% efficient; each process produces pollution. TYPES OF POLLUTION 1. Air Pollution 2. Water Pollution 3. Land Pollution 4. Noise Pollution
Air Pollution Air pollution is the major form of pollution in which duration and concentration of pollutant is important. Definition ‘Any substance that is introduced by human activities or through natural processes for such a duration and concentration is considered to be a pollutant and pollutants are responsible for causing air pollution’
Sources of Air Pollution § Natural Sources Volcanic Eruptions, biological decay, marshes, oceans, pollen grains § Anthropogenic Sources Automobiles, Coal burning power plants, Industries, Domestic Fuel consumption, cigarettes, electronic appliances, aerosols and sprays.
Categories of Air Pollution § Primary Air Pollutant Harmful substance that is emitted directly into the atmosphere § Secondary Air Pollutant Harmful substance formed in the atmosphere when a primary air pollutant reacts with substances normally found in the atmosphere or with other air pollutants
Major Classes of Air Pollutants § § § Particulate Material Nitrogen Oxides Sulfur Oxides Carbon Oxides Hydrocarbons Ozone
Particulate Material Thousands of different solid or liquid particles suspended in air n Includes: soil particles, soot, lead, asbestos, sea salt, and sulfuric acid droplets Dangerous for two reasons n May contain materials with toxic or carcinogenic effects n Extremely small particles can become lodged in lungs
Nitrogen and Sulfur Oxides Nitrogen Oxides n Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at high temperature n Problems o Greenhouse gases o Cause difficulty breathing Sulfur Oxides n Gases produced by the chemical interactions between sulfur and oxygen n Causes acid precipitation
Carbon Oxides and Hydrocarbons Carbon Oxides n Gases carbon monoxide (CO) and carbon dioxide (CO 2) n Greenhouse gases Hydrocarbons n Diverse group of organic compounds that contain only hydrogen and carbon (ex: CH 4 - methane) n Some are related to photochemical smog and greenhouse gases
Ozone Tropospheric Ozone n Man- made pollutant in the lower atmosphere n Secondary air pollutant n Component of photochemical smog Stratospheric Ozone n Essential component that screens out UV radiation in the upper atmosphere n Man- made pollutants (ex: CFCs) can destroy it
Sources of Outdoor Air Pollution Two main sources n Transportation n Industry Intentional forest fires is also high
Effects of Air Pollution Low level exposure n Irritates eyes n Causes inflammation of respiratory tract Can develop into chronic respiratory diseases
Health Effects of Air Pollution Sulfur Dioxide and Particulate material n Irritate respiratory tract and impair ability of lungs to exchange gases Nitrogen Dioxides n Causes airway restriction Carbon monoxide n Binds with iron in blood hemoglobin n Causes headache, fatigue, drowsiness, death Ozone n Causes burning eyes, coughing, and chest discomfort
Children and Air Pollution Greater health threat to children than adults n Air pollution can restrict lung development n Children breath more often than adults Children who live in high ozone areas are more likely to develop asthma
AIR POLLUTION CONTROL Cannot be fully prevented but can be controlled. 1. Preventative measures 2. Control measures using equipments. Preventative measures (source control) Selection of suitable fuel. (Low sulphur coal in power plant, using of CNG) Modification in industrial process. Selection of suitable site and zoning for industrial unit.
CONTROL MEASURES § § § When source control not possible some measures taken to prevent pollution. Collecting pollutants by using equipments. Destroying the pollutants by thermal or catalytic combustion. Changing the pollutants to less toxic form. By releasing the pollutants through tall chimneys for greater dispersion.
Other Ways to Improve Air Quality Reduce sulfur content in gasoline from its current average. Require federal emission standards for all passenger vehicles n Including SUVs, trucks and minivans Require emission testing for all vehicles n Including diesel
1. Global Warming 2. Acid Rain 3. Deforestation