Air pollution influences our health in many ways. No air means death. Though we can't see it, there is air around us. Air is everywhere and it gives a life to every living things. But bad air makes people ill. In the city, there are a great many people and there are too many cars running on the road. The cars send out bad gases (气体). There are many factories too. From the chimneys (烟卤) of these factories, we get the smoke usually in black colour. Every day we breathe it in and out. This makes us feel sick. When people talk about air pollution, they are usually thinking about outdoor air pollution. But a lot of air pollution comes from indoor activities such as smoking and cooking. Indoor air pollution can hurt people's eyes, noses and throats. So air pollution, both indoor and outdoor, can also lead to lung cancer (肺癌) and heart disease.

    Everyone should help fight against pollution. In order to keep us healthy, we have to go out to the countryside to breathe more fresh air. Or we can climb up hills to get more fresh air.