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Weather II HI, Without further ado, let’s carry on with the subject of pollution. What is air pollution? Air pollution is defined as substances or radiations in the atmosphere, which harm living organisms or their environment. Normally, as we have seen, the atmosphere is self-purifying. However, when a high concentration of unnatural wastes is discharged into the air, then the atmosphere becomes overburdened and polluted. Eventually the pollutants in the air may be precipitated from the atmosphere when it rains. When this occurs, the pollution falls onto the land or water, and contaminates this part of the environment. Air pollution is caused in one of three ways: surface friction, vaporization, and combustion. Friction is a minor cause of air pollutants. Such things as sawing, drilling and grinding various materials release airborne particles which may find their way into our lungs eventually. For most people, friction is not a major source of pollution unless they are workers in a mine, mill or industry that releases small particles into the air. Vaporisation occurs when a liquid becomes a gas. A good example is paint thinner. When the can is opened, certain fumes escape as vapour into the atmosphere. Petrol also undergoes vaporization, as do paint, glues, and other chemical compounds. This is only a major source of pollution when a nearby industry is engaged in making these products, or is working with rubber or plastic, which can also vaporize. Combustion is the real villain as the cause of air pollution. Combustion is simply the burning of a solid liquid into a gas. For instance, your car works on combustion by turning petrol into various hot gasses. When combustion occurs, heat and light are usually released. Unfortunately, other chemicals and gasses are also released into the atmosphere. Some of these chemicals are harmful, and are the major factor in polluting our air. In fact, a quick study of the air pollution problem is really just a description of these chemicals and how they get into our atmosphere. Let’s discuss some of the major chemical pollutants and the harm they can do to us: SULPHUR DIOXIDE: "It smells like hell around here" a worker complained to his boss. What he was talking about was the chalking, sulphur fumes that came from the worker’s plant. Sulphur dioxide does, indeed, remind you of the "fire and brimstone" odour. If you breathed a deep lungful of the gas, it would feel like thousands of razor blades in your lungs. Sulphur dioxide is one of the deadliest air pollutants, and it accounts for about 18% of all air pollution. Sulphur dioxide has been implicated in cases of asthmatic attacks, eczema, breathing difficulties, and paralysis and corrosion of the respiratory organs. As soon as sulphur dioxide rises to a concentration of only one-five millionth of the atmosphere, death increases rapidly. Coal-burning plants and industries account for almost 85% of all sulphur dioxide pollution. Residential use of coal and fuel oil makes up another 10% of the sulphur dioxide release. The problem of sulphur dioxide pollution is the most serious in areas where coal burning is the most widespread. No one, however, can escape the harmful effects of sulphur dioxide because it is spread all over the earth in “acid rain”. Acid rain occurs when the particles of sulphur dioxide are carried through the air and combine with water particles and fall to earth. Along with the water in the rain, you also get the acid waste products of sulphur dioxide. Crops that are especially susceptible to sulphur dioxide and acid rain are wheat, barley, oats, cotton, alfalfa, buckwheat and white pine. These sulphur compounds also enter the streams, rivers and lakes after they fall from the air. As a result, many fish and aquatic plants quickly die. The only contribution we can do as individuals is to use another form of heating besides coal and fuel oil. Something to remember next winter! To be continued... Have a great week, The Crazy Nut Team