Air pollution is very serious. Anything that can make the air quality worse is an air pollutant. At present, there are about 100 kinds of air pollutants, which can be divided into two types according to their existing state: one is aerosol pollutants, and the other is gas pollutants. Aerosol pollutants mainly include dust, smoke droplets, fog, dustfall, floating dust and suspended solids. Gaseous pollutants mainly include sulfur oxides mainly with sulfur dioxide, nitrogen oxides mainly with nitrogen dioxide, carbon oxides mainly with carbon dioxide and hydrocarbons combined with hydrocarbons.