Factories pollute the air by pumping out chemicals that are harmful for all the living things. That is why there is acid rain and global warming. There is a lot of science involved in this, Factories can pollute the environment through thermal pollution, chemical pollution, air pollution, noise pollution, for a few examples. Thermal pollution is when hot water is dumped into cool water in a river, lake, pond or bay. The difference in temperatures can promote algae growth, kill of native fish or wildlife, or it might cause disruptions in the water that causes the water to change temperature, also causing major problems with wildlife. Chemical Pollution is when chemicals are exposed to the environment, either by dumping them into sewage plants, where excess waste ends up in the ground. A good example of this is nuclear waste. This needs to be treated carefully or else it could completely destroy an area. Air pollution is when pollution is mixed in with the air. Noise pollution is when a factory causes a lot of noise... enough to affect the surrounding environment.
