WHO state that diesel exhaust fumes do cause cancer

According to a panel of experts working for the World Health Organisation, exhaust fumes from diesel engines were definitely a cause of lung cancer and may also cause tumours in the bladder. It based the findings on research in high-risk workers such as miners, railway workers and truck drivers. However, the panel said everyone should try to reduce their exposure to diesel exhaust fumes.

Dr Christopher Portier, who led the assessment, said: "The scientific evidence was compelling and the Working Group's conclusion was unanimous, diesel engine exhaust causes lung cancer in humans. "Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide."

The impact on the wider population, which is exposed to diesel fumes at much lower levels and for shorter periods of time, is unknown. Dr Kurt Straif, also from IARC, said: "For most of the carcinogens when there is high exposure the risk is higher, when there is lower exposure the risk is lower."

So what has this to do with running?

It's just a reminder that you should think about where you run. Try to avoid running alongside busy congested roads if possible. There may be alternative routes through housing estates, parks or walkways.

In another study done recently, it was found that even in large cities, the health benefits of running  far outweighed the option of staying indoors and doing nothing. So it's not a question of if you should run in a busy area but rather where.