Question

some points about control of air pollution

Answer 1

There are other  way to reduce emissions besides using pollution control  equipment --prevent emission to begin  with. Air quality permit  help minimize ,reduce or prevent  emission as much as possible by placing requirements on how things are done.
permits can specify the quantity ,type or quality of fuel or other substance used in a process.
Engineers can also set combustion specifications to minimize emission. 

Answer 2

Explanation:

Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's also called smog. Some air pollutants are poisonous.