Air pollution in the UK is usually of a low level that is unlikely to provoke any serious short-term side effects to people in generally good health. However, on rare occasions where air pollution levels are particularly high, some people may suffer from eye irritation or coughing. Breathing may become uncomfortable for those in poorer respiratory health.
People who suffer from asthma may find that high levels of air pollution causes them to use their inhalers more often or it may even cause an attack. There is very little evidence to suggest that air pollution is a cause of asthma in adults or children.
One of the main pollutants from vehicle emissions is Nitric Oxide, which through oxidation creates Nitrogen Dioxide. It plays a major role in atmospheric reactions that produce ground-level ozone or ‘smog’. This is the main pollutant by which air quality is assessed and thus concentrations of nitrogen dioxide more than any other pollutant determine the extent of an Air Quality Management Area (AQMA).
Smoking can increase your vulnerability to the short-term effects of air pollution and will have a much greater effect on your health overall. Diseases of the lungs and heart that are attributed to smoking can also be affected by poor air quality.
More information on air and health effects can be found here.