Q: I’d like to know what kind of damage I may be doing to my mouth, throat and lungs by riding in heavy traffic every day on my commute through London. I use a mask but I find it to be rather ineffective as I can always smell vehicle exhaust while using it, and I get to the end of a week constantly clearing my throat. Have there been any studies done on this issue?

Alex Araujo, email

A: Petrol and diesel exhaust fumes, latex particles from friction of car tyres, and similar particles of less than 10-micron diameter (known as ?particulates?) are the most common chemicals prevalent in heavy traffic. Yes, they are harmful to human health.

Several studies have shown an alarming increase with asthma, rhinitis, and cardiovascular problems in high-density cities. Of these, asthma, sinus or throat problems are more likely to be reversed quickly, once away from a polluted environment. People who previously had asthma, due to dust mites or other natural allergens, are more likely to get their allergies exacerbated by traffic pollutants, because they are prone to experience the effects of carbon monoxide and dioxide.

The results of a study published recently show a direct link of increased incidents of heart attacks with high levels of traffic pollution. Some of these particulates have also been associated with some common cancers: the longer one’s exposure to these, the higher the risk. However, the risk also depends on the person?s natural detoxification mechanisms of the cells which are influenced by diets high in antioxidants (vegetables and fruits).

Dr Appelles Econs

(Director of three specialist allergy centres in the UK, and member of the British Society of Allergy, Environmental and Nutritional Medicine)