These dangerous pollutants are known as the criteriapollutants, and include ozone, particulate matter, sulphur dioxide, nitrogen dioxide, carbon monoxide, and lead
Natural processes produce relatively small amounts. Carbon monoxide reacts with other pollutants in the air to form potentially harmful ground level ozone. ... Inhalation of carbon monoxide at high concentrations can be fatal, because it prevents the transport of oxygen (in blood) around the body.