Air Pollution PDF

Air Pollution Indoor Air Pollution Outdoor Air Pollution INDOOR AIR POLLUTION ● Almost three billion people worldwide continue to depend on solid fuels, including biomass fuels (wood, dung, agricultural residues) and coal, for their energy needs. ● Cooking and heating with solid fuels on open...

Air Pollution Indoor Air Pollution Outdoor Air Pollution INDOOR AIR POLLUTION ● Almost three billion people worldwide continue to depend on solid fuels, including biomass fuels (wood, dung, agricultural residues) and coal, for their energy needs. ● Cooking and heating with solid fuels on open fires or traditional stoves results in high levels of indoor air pollution. ● Indoor smoke contains a range of health-damaging pollutants, such as small particles and carbon monoxide, and particulate pollution levels may be 20 times higher than accepted guideline values. Impact on Health ● There is consistent evidence that exposure to indoor air pollution can lead to- ● Acute lower respiratory tract infections in children under five, and ● Chronic obstructive pulmonary disease ● Lung cancer (where coal is used) in adults. ● Adverse pregnancy outcomes http://www.who.int/mediacentre/factsheets/fs292/en/index.html INDOOR AIR POLLUTION Pollutant Sources Respirable particles Tobacco smoke, stove, aerosol spray Carbon monoxide Combustion equipment, stove, gas heaters Nitrogen dioxide Gas cookers, cigarettes Sulphur dioxide Coal combustion Carbon dioxide Combustion, respiration Formaldehyde Combustion, respiration, particle board, carpet adhesives. Insulation Other organic vapours (benzene, toluene etc.) Solvents, adhesives, resin products, aerosol sprays Ozone Electric arcing, UV light sources Radon Building material Asbestos Insulation, fireproofing Mineral fibres Appliances Outdoor Air Pollution Sources of Outdoor Air Pollution ● Combustion of Petroleum and other hydrocarbon fuels in cars, trucks, and airplanes ● Burning of fossil fuels (oil, coal) ● Industrial processes ● Herbicides ● Everyday radioactive fallouts ● Dust from fertilizers ● Mining operations ● Livestock feedlots Major Outdoor Air Pollutants 1. 2. 3. 4. 5. 6. 7. 8. Carbon monoxide Sulphur dioxide Lead Carbon dioxide Hydrocarbons Ozone Particulate matter Polycyclic aromatic hydrocarbons Particulate Matter ● Particulate Matter affects more people than any other pollutant. ● The major components of Particulate Matter are sulfate, nitrates, ammonia, sodium chloride, carbon, mineral dust and water. ● It consists of a complex mixture of solid and liquid particles of organic and inorganic substances suspended in the air. ● The particles are identified according to their aerodynamic diameter, as either PM10 or PM2.5 . ● The latter are more dangerous since, when inhaled, they may reach the peripheral regions of the bronchioles, and interfere with gas exchange inside the lungs. Guideline values: PM2.5 10 µg/m3 annual mean 25 µg/m3 24-hour mean PM10 20 µg/m3 annual mean 50 µg/m3 24-hour mean ● ● Ozone ● ● ● ● ● Ozone at ground level – not to be confused with the ozone layer in the upper atmosphere – Major constituents of photochemical smog. It is formed by the reaction with sunlight (photochemical reaction) of pollutants such as nitrogen oxides (NOx) from vehicle and industry emissions and volatile organic compounds (VOCs) emitted by vehicles, solvents and industry. The highest levels of ozone pollution occur during periods of sunny weather. Guideline values: 100 µg/m3 8-hour mean Nitrogen dioxide(NO2) ● ● ● ● It is a toxic gas which causes significant inflammation of the airways. NO2 is the main source of nitrate aerosols, which form an important fraction of PM2.5 and, in the presence of ultraviolet light, of ozone. The major sources of anthropogenic emissions of NO2 are combustion processes. Guideline values: 40 µg/m3 annual mean 200 µg/m3 1-hour mean Sulphur dioxide ● ● ● ● SO2 is a colorless gas with a sharp odour. It is produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores that contain sulfur. Studies indicate that a proportion of people with asthma experience changes in pulmonary function and respiratory symptoms after periods of exposure to SO2 as short as 10 minutes. Guideline values: 20 µg/m3 24-hour mean 500 µg/m3 10-minute mean Carbon Monoxide ● ● ● ● ● One of the most common and widely distributed air pollutant Properties: colorless, odorless, heavier than air, 0.0036% of atmosphere Effects: binds tighter to Hemoglobin (Hb) than O2, so organs do not get O2 needed, causes drowsiness, impairs mental functions and visual acuity, even at low levels. Sources: incomplete combustion of fossil fuels 60 - 95% from auto exhaust 1 billion tons enter atmosphere/year Effects of air pollutants on health ● Chronic bronchitis ● Lung cancer ● Bronchial asthma ● Emphysema ● Respiratory allergies ● Skin allergies ● Ophthalmic problems Effects on the environment ● Smog ● Acid rain ● Ozone depletion ● Global warming Smog ● With the introduction of petroleum to replace coal economies in countries, photochemical smog has become predominant in many cities, which are located in sunny, warm, and dry climates with many motor vehicles ● Worst episodes of photochemical smog tends to occur in summer Constituents of smog ● Particulates (especially lead) ● Sulphur Di-oxide ● Nitrous oxides ● Potassium ● Carbon monoxide ● Other toxic chemicals A smoggy city Acid Rain ● When emissions of sulfur dioxide and nitric oxide from stationary sources are transported long distances by winds. ● They form secondary pollutants such as nitrogen dioxide, nitric acid vapor, and droplets containing solutions of sulfuric acid, sulfate, and nitrate salts Acid Rain ● These chemicals descend to the earth's surface in wet form as rain or snow and in dry form as a gases fog, dew, or solid particles, it is known as acid rain or acid deposition Effects of Acid rain ● contains high levels of sulfuric or nitric acids ● contaminate drinking water and vegetation ● damage aquatic life ● erode buildings ● Alters the chemical equilibrium of some soils The Greenhouse Effect ● CO2 is a good transmitter of sunlight, but it also partially restricts infrared radiation going back from the earth into space, which produces the socalled greenhouse effect that prevents a drastic cooling of the Earth during the night