tly from natural sources such as soil dust, pollen grain, volcanic and forest fire ashes and dust. Human activities also contribute considerably to air pollution. These mainly come from dust, soot, and ashes from combustion and incineration. Industry, mining, power generation, transportation and construction are sources of particulates in air pollution. Burning of fuels alone adds close to a billion tons of particulates in the air ( Sandak pg. 90). Particulates can cause breathing problem and other respiratory diseases. It can also act as an effective sun block by reflecting light back into the stratosphere, and thus preventing photosynthesis ( Gutnik pg. 18). Aerosol are also particles, but they are so tiny that they stay afloat in the air and are not easily pulled by the gravity to settle down. Smoke and fog are common examples of aerosol that occurs in the nature. The most common solid aerosol are mineral dusts, fly ash ( including metal dusts), sodium carbonate, calcium sulfate from industrial process, and sodium chloride from sea salt. Another major aerosol product is the CFC (chlorofluorocarbon) gas that was used as a propellant gas from pressurized cans. CFC gases, when released, tend to go upward and reach the stratosphere where it destroys the ozone layer ( Sandak pg. 28 ). Air pollution has many impacts on earths ecosystem. Clouds containing sulfur and nitrogen oxides form acids as they mix with water vapor, and cause acid rain. Acid rain clouds may be carried by the winds hundreds of miles away from their sources. This causes a problem because no one knows where it came from, and we can not fix it unless we know the source. Acid rain that is between ten and seventy times more acidic than unpolluted rain is common in much of North America and Europe. Acid rain directly affects many aspects of life. It can damage entire forests. Acid river water may flow into lakes, making them acidic. Some fish can adapt to...
