Environmental Problems Caused by Local Air Pollution
A wide range of compounds can cause local air pollution. The emissions of sulfur dioxide, nitrogen oxides, carbon monoxide, fine particulate matter, organic compounds like benzene, toluene and poly-aromatic hydrocarbons (PAH), and heavy metals in particulate matter (lead, cadmium) can cause local concentrations to reach levels which are harmful to human health.
Some compounds like nitrogen oxide and volatile organic compounds cause air pollution problems in stagnant air, as the reactions between these compounds form ozone and other oxidants. Ozone is at present (2006), together with particulate matter, the most serious pollutant in cities in developed countries. It is also becoming very problematic in developing countries.