Pollution comes in many forms. I have three categories in which there are subcategories. The first one is air pollution (covers acid rain, global warming and Ozone break down), the second one is water pollution (waste dumping, eutrophication and over fishing), and the last is land pollution (deforestation (loss of habitat) and pesticides).
1. Air Pollution
Fossil fuels, such as coal, oil and natural gas all come from plants and they contain sulphur and nitrogen. When it is burnt for energy it reacts with the oxygen in the air giving out sulphur dioxide and nitrogen oxide. This normally comes from industries like power stations and from cars. Sulphur dioxide is a very unpleasant gas that is poisonous to plants and humans.
What forms in the rain
SO2 + H2O H2SO2 (Sulphurous Acid)
NO2 + H2O H2NO3 (Nitrous Acid)
CO2 + H2O H2CO2 (Carbonic Acid)
As the gases are given off they dissolve into the rain becoming an acid, causing the PH to decrease to as low as 4 (normal rain is a little below 7).
This produces acid rain which falls into lakes, rivers and soil. The acid rain seeps into the soil, and washes out ions such as calcium, magnesium and aluminium, which are vital for plants to survive. These get washed into rivers and poisons fish because the aluminium ions affect their gills. The situation becomes worse as the acid rain makes the water inhabitable to plants and animals.
Some acid rain clouds can drift all the way from England to Norway, so other countries are pulled into the problem. Most of the problems that come from acid rain have been raised, and most of the coal power plants (the biggest pollution) have been shut down. Most of them use oil because that burns more...