Exhaust emissions: what are they?
The exhaust fumes from a car or lorry’s engine contains a large number of different chemicals or emissions.
Once released into the air, exhaust emissions are breathed in and transported in the bloodstream to all the body's major organs. Diesel seems potentially to be more of a problem than petrol.
Potentially dangerous vehicle emissions include:
Carbon monoxide
Carbon monoxide
Nitrogen dioxide
Sulphur dioxide
Benzene
Formaldehyde
Polycyclic hydrocarbons
Lead
Tiny suspended particles (‘particulate matter’)
What are the risks?
Although research has clearly linked exhaust emissions to a range of health problems in the population, the exact risk to any individual is difficult to define. However there is no doubt that the more you are exposed the greater the risk is likely to be and some people, for example those who already have respiratory conditions such as asthma or bronchitis, are especially vulnerable.
http://www.bbc.co.uk/health/physical_health/conditions/exhaust_emissions.shtml