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 Air pollution is an undesirable change in the physical, chemical and biological characteristics of air, which adversely affects human beings, plants,

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Presentation on theme: " Air pollution is an undesirable change in the physical, chemical and biological characteristics of air, which adversely affects human beings, plants,"— Presentation transcript:


2  Air pollution is an undesirable change in the physical, chemical and biological characteristics of air, which adversely affects human beings, plants, animals and materials.  Air is a mixture of gases that include nitrogen (78%), oxygen (21%), carbon dioxide (0.04%) and several inert substances like argon (1%), helium, xenon, neon and krypton.

3 PollutantsSources Sulfur oxides, particulatesVolcanoes CO, CO 2, nitrogen oxides, particulatesForest fires DustWindstorms Hydrocarbons, pollensLive plants Methane, hydrogen sulfideDecaying plants Viruses. DustSoil Salt particulatesSea 1. Natural Sources such as volcanoes, forest fires and windstorms

4 2. Transportation is the greatest source of air pollution producing nearly 70% of CO, 39% of nitrogen oxides, 30% hydrocarbons, 21% of particulates, and 4.8% of sulfur oxides in the air. Waste products get into the air as a result of the combustion of fuel. Transportation includes automobiles, trucks, jets and trains. 3. Fuel combustion at stationary sources include most power plants and factories. These sources release 79.8% of sulfur oxides, 56.4% of nitrogen oxides, 26.2 of particulates, 7.5% of carbon monoxide and 4.0% of hydrocarbons in the air. 4. Industrial processes such as in smelters, petroleum refineries, paper mills, and synthetic rubber manufacturing plants that are responsible for 47% of hydrocarbons, 34.4% of particulates, 15.2% of sulfur oxides, 7.5% of carbon monoxide, and 3.2% of nitrogen oxides in the air.

5 Pollutants that come from motor vehicles, power plants, factories, and different industrial processes are called anthropogenic pollutants since they are products of human activities.


7 The biggest quantity of carbon monoxide (CO) comes from fuel combustion at stationary sources. This colorless, odorless and poisonous as may also come from forest and building fires, agricultural burning and miscellaneous types of burning. Emission of CO may be prevented by supplying enough air to ensure complete combustion to form carbon dioxide When CO concentration is high especially in heavy city traffic, it can make you tired, drowsy, and careless. You might even experience headache and nausea when there is a heavy concentration of CO in the air

8  When sulfur dioxide from engine exhausts and factory chimneys is taken in, it attacks the respiratory system in humans and other animals.  It dissolves in rain to give acid rain  Acid rain damages buildings, metalwork, stonework and plants.  Rainwater having a pH below 5.6 is called acid rain

9 When coal is burned, the sulfur content is oxidized to form corrosive sulfur dioxide gas, particles and droplets, which can find their way into the tiny crevices of the lungs, destroying cells and impairing oxygen absorption. Detection of harmful pollutants becomes difficult due to changing environmental variables such as winds, temperature, humidity, precipitation and concentration of other compounds

10 Nitrogen oxides usually come from automobiles and power plants that burn fuels at very high temperatures. Nitrogen dioxide (NO2) in the atmosphere is reduced to nitrogen monoxide (NO) and atomic oxygen by ultraviolet light. Atomic oxygen reacts with an oxygen molecule to form ozone (O3). Finally, ozone reacts with nitrogen monoxide to form nitrogen dioxide and oxygen. This is the most common type of nitrogenous air pollutant. Nitrogen dioxide, a pungent and harmful gas, causes nose and eye irritation at 13 parts per million (ppm) and pulmonary discomfort at 25 ppm. Like sulfur dioxide, nitrogen oxides affect the respiratory system and cause acid rain.

11 Unlike carbon monoxide, hydrocarbons at the concentrations normally found in the atmosphere are not toxic. However, they are major air pollutants because their role in the production of photochemical oxidants. More than half of the hydrocarbons come from transportation vehicles. They are unburned gases that come from petroleum fuels. Hydrocarbons can cause liver damage and even cancer.

12 Particles of solids or liquids ranging from visible to microscopic size are produced by fuel combustion. Lead from tetraethyl lead, the most abundant particulate matter produced by transportation vehicles, is discharged into the air through car exhausts. Tars, resins, asbestos, and some particulates are products of mechanical devices and processes. Secondary pollutants are produced in the atmosphere by the reactions of primary pollutants with each other and with the constituents normally found in the atmosphere. Primary pollutants are easier to identify and control because their sources can be readily found and regulated. Secondary pollutants are quite complex in nature and much more difficult to control.

13 These pollutants originate from hydrocarbons and nitrogen oxides emitted from transportation and from stationary combustion sources. They require light energy to undergo photochemical reactions. The hydrocarbons react with nitrogen dioxide to give peroxyacyl nitrate (PAN) compounds. Ozone reacts with hydrocarbons to produce aldehydes.

14 Primary pollutants often react with one another or with water vapor. Secondary pollutants are chemical substances produced from the chemical reactions of natural or anthropogenic pollutants and reactions powered by energy from the sun. Example: sulfur dioxide released from coal-fired power plants, react with oxygen and water in the atmosphere to produce sulfuric acid.

15 1. Health Effects Short Range Effects - colds, coughs, rhinitis, inflammation of the respiratory tract, aggravation of asthma increases when levels of sulfur dioxide rise. - headache, dizziness, decreased physical performance due to carbon monoxide from automobile fumes - irritation of the lungs due to acute exposure to nitrogen oxides - respiratory and eye irritation develop when people are exposed to photochemical oxidants Long Range Effects - emphysema, lung cancer and bronchitis

16 2. Effects on animals and plants - fluoride and arsenic poisoning have occurred in cattle that graze near metal smelters - acids produced from industrial boilers, power plants and smelters have been observed to be harmful to fish and other wildlife - ozone, sulfur dioxide and sulfuric acid are pollutants most hazardous to plants. Ozone make plants brittle. Sulfur dioxide causes spotting of leaves. 3. Effects of buildings and materials - sulfur dioxide, sulfuric acid and hydrogen sulfide corrodes buildings and other concrete structures - sulfuric acid and nitric acid cause damage to metals and reduce their strength - hydrogen sulfide tarnishes silver and blacken leaded house paints - ozone cracks rubber windshield wipers, tires and other rubber products

17 The Carbon Dioxide Cycle How is carbon dioxide produced? industry, transportation, factories and homes, electric power generation, forest fires How is it consumed? Utilization of plants in photosynthesis, solution in the ocean followed by precipitation What is Greenhouse Effect? Rise in global temperature due to the trapped heat (infrared radiation) in the earth’s atmosphere. Other gases that reradiate infrared radiation to the earth aside from carbon dioxide are methane, nitrous oxide and chlorofluorocarbons.


19 During pregnancy – retards the rate of fetal growth and increases the risk of spontaneous abortion, fetal death, and deaths of otherwise normal newborn babies. Deficiencies in physical growth, intellectual development, and emotional development are experienced by children of smoking mothers The damaging effects of smoking are greater for: 1. industrial workers exposed to toxic agents 2. workers in asbestos, rubber, coal, uranium, textile and chemical industries.

20 Carbon Monoxide (in cigarette smoke) – binds chemically with hemoglobin (the substance that carries oxygen to the cells) thereby reducing the amount of oxygen delivered to the tissues of the body Nicotine – a poisonous alkaloid which adversely affects the circulatory system especially the heart. These effects include increase of heartbeat rate, blood pressure and cardiac output. It also causes constriction of the bronchial tubes in the lungs Tar – a polycyclic aromatic hydrocarbon which is carcinogenic

21 Ozone is produced by the action of sunlight on motor vehicle exhausts and by the transformers of power company substations Ozone is produced when nitrogen dioxide decomposes into nitrogen oxide and oxygen in the presence of sunlight and hydrocarbons. Much of the nitrogen dioxide and hydrocarbons come from auto exhausts. While ozone is forming, the reaction of nitrogen oxide and hydrocarbons produces peroxyacyl nitrates (PAN) and formaldehyde, which causes eye irritation. The resulting pollutio is called photochemical smog. Ozone is poisonous even in small concentrations of as little as 1ppm. It causes serious damage to plants and animals. Ozone destroys organic matter. It deteriorates and cracks rubber.

22 Industrial plants emit the same type of pollutants as motor vehicles. Great quantities of sulfur oxides are liberated due to the burning of large amounts of bunker oil and coal with a high sulfur content Small amounts of dust, sawdust, cement, sand and others are produced from mechanical operations Acid mists and other liquid aerosols are released from volatile liquids and leakages from chemicals and acid plants Power plants and iron and steel industrial plants produce particulate matter

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