Identify two different forms of global pollution issues and describe how each may harm the natural environment.

Industries, as well as emissions from vehicles increase the sulphur dioxide and nitrogen oxides percent in the air. These emissions change into sulphates and nitrates under the influence of sunlight and moisture, and get converted into sulphuric acid and nitric acid, which come down as acid rain. Coal generally contains between 2 - 3 % sulphur, and when it is burned, this sulphur is released into the atmosphere. Electric companies and other industries which burn coal cause a lot of emission of sulphur dioxide.

The major source of emissions of nitrogen oxides into the air is from vehicles and other places where fossil fuels are burned. Forest fires, often caused by man, either deliberately or accidentally, are another source of pollution.

Secondly the other source of polluting is volcanic activity, lightning, or organic decay, also gives rise to an increase in atmospheric pollutants but not much can be done about these causes. However over 90% of sulphur dioxide emissions and around 95% of nitrogen oxides released into the air are from manmade sources.

• Effects of acid rain on plant life. The roots are damaged by acidic rainfall, causing the growth of the plant to be stunted, or even in its death. Nutrients present in the soil, are destroyed by the acidity. Plant reproduction is also inhibited by the effects of acid rain.
• Effects on animals and birds. All living organisms are interdependent on each other. If a lower life form is killed, other species that depended on it will also be affected. Every animal up the food chain will be affected. Animals and birds, like waterfowl or beavers, which depended on the water for food sources or as a habitat, also begin to die. Due to the effects of acid rain, animals which depended on plants for their food also begin to suffer.

The second globally polluting issue is Greenhouse gases and the global warming

• The Greenhouse gases are naturally found in air. They include carbon dioxide, methane and nitrous oxide. They trap heat in the atmosphere and keep the Earth's surface much warmer than it would be the mean temperature of the earth would be about −19 °C rather than the present mean temperature of about 15 °C. This warming effect is called the natural greenhouse effect. In the last 200 years, the amount of greenhouse gases in the air has been increasing, due to human activities. Mankind has been increasing the amount of carbon dioxide, methane and nitrous oxide in the air, and has even been adding completely new greenhouse gases to the atmosphere.