What is air pollution?
A big problem is that the atmosphere surrounding the Earth is getting dirty. When gases in the air that make the atmosphere dirty increase, we call this air pollution. Air pollution causes many problems. But it is people who originally created the causes of air pollution.
The biggest cause of air pollution is burning things. When we burn oil or coal to produce energy or when we burn large amounts of garbage, substances are created that pollute the atmosphere. For example, smoke from factories and exhaust gas from cars have many substances that cause pollution.
Nitrogen oxides are one kind of polluting substance. We know nitrogen oxides are the cause of photochemical smog. Acid rain, which kills plants, is also caused by nitrogen oxides. Air pollution is very bad near factories or busy roads. But even if there are no factories or big roads nearby, polluted air is still carried by the wind.
