• Sulphur Dioxide
• Nitrogen oxides
• Fine Particles
• Ozone and volatile organic compounds
• Toxic Organic Micro-Pollutants (TOMPS)
• Benzene
• 1,3-Butadiene
• Carbon monoxide
• Lead and Heavy Metals

TOMPs are produced by the incomplete combustion of fuels. They comprise a complex range of chemicals some of which, although they are emitted in very small quantities, are highly toxic or carcinogenic. Compounds in this category include:

• PAHs (PolyAromatic Hydrocarbons)
• PCBs (PolyChlorinated Biphenyls)
• Dioxins
• Furans

TOMPS can causing a wide range of effects, from cancer to reduced immunity to nervous system disorders and interfere with child development. There is no "threshold" dose - the tiniest amount can cause damage.