The two major air pollutants produced by industry and power stations are sulphur dioxide and nitrogen oxides.
Sulphur dioxide is the main pollutant given off by power stations.
Sulphur dioxide was once a major air pollutant in cities. It would mix with smoke given off when coal was burnt to produce smog . Today, industries that emit sulphur dioxide must have chimneys or stacks which release the waste gases into the atmosphere at higher levels, thereby reducing the amount of ground level pollution. Power stations are now also required to reduce the amount of sulphur dioxide they give off by using specialised clean technology. Nitrogen oxides are pollutants which are mainly associated with car exhausts, although some comes from industry.