Acid rain is just rain which is acidic. The rain becomes acidic because of gases which dissolve in the rain water to form various gases. About 70 percent of acid rain comes from sulphur dioxide (SO2), which dissolves into the water to form sulphiric acid. The rest comes from various oxides of nitrogen (mainly NO2 and NO3). These gases are produced almost entirely from burning fossil fuels, mainly in power stations and road transport. Because rain travels over long distances in clouds, acid rain is a global problem. Unfortunately there is no in expensive way to fix this kind of pollution.

About 37 percent of the smoke in our atmosphere is generated in people's homes, and most of this is from coal fires. These produce much more tar and hydrocarbons than an equivalent-sized industrial furnace, and used to be a major contributor to smog. A way to fix this is to use smokeless fuels in your home and in your community.

Smog looks like a mixture of smoke and fog, which is why it is called smog. It is made up of particulates that are triggered by sunlight. Smog tends to form in urban areas where there are lots of cars and especially where the air is heavy. A few ways to help stop smog are avoiding using cars when pollution levels seem to be high. Or not using a car for going on short trips.

The earth is kept warm by its atmosphere and as it heats it lets off infra-red radiation. Some of this heat is trapped inside the atmosphere so sometimes the earth is warmer than it should be, like a greenhouse. Some simple ways for helping prevent the greenhouse effect are turn off all the lights when you leave a room, make sure you get insulation for your house, and use electronics that use only a little electricity.