Traffic fumes linked to higher lung cancer risk

kade rechteroever

Living near a busy road can increase the risk of lung cancer, according to a large study that will increase the pressure on governments to reduce air pollution.


Commuters struggle through traffic snarls on the M5 motorway in Sydney, a regular peak-hour experience for motorists. Picture: Tomasz Machnik Source: The Australian

Even low levels of traffic fumes have risks comparable with passive smoking, according to researchers, who say that pollution should be added to a World Health Organisation list of recognised causes of lung cancer. The risk increases by roughly 20 per cent when moving from clean areas to moderately polluted ones, and by the same again when moving to the most polluted zones, the international survey found.

Researchers say that, while the risks to an individual are low, air pollution must be considered a serious public health problem. They looked at 17 previous studies that had collected data on 313,000 people around Europe, and recorded pollution levels where they lived. Of those, 2,095 developed lung cancer, or 0.67 per cent.

Airborne particles smaller than 2.5 micrometres in diameter, known as PM2.5, and those smaller than 10 micrometres in diameter, known as PM10, were both linked to lung cancer.

"The more traffic nearby, the more particles; and the more densely populated the area, the more particles," said Ole Raaschou-Nielsen, of the Danish Cancer Research Centre in Copenhagen, who led the study. "Both traffic and the degree of urban development matters."

For every extra 5micrograms of PM2.5 in a cubic metre of air, lung cancer risk increases by 18 per cent, his team reports in The Lancet Oncology. For every extra 5 micrograms of PM10 in a cubic metre, the risk increases by 22 per cent, even after adjusting for class, wealth and other factors linked to lung cancer.

This rule held even at levels considered safe by the EU, Dr Raaschou-Nielsen said. "We found no threshold below which there was no risk."

Data from London and Oxford used in the study found that PM2.5 levels varied from 8-18 micrograms per cubic metre and PM10 levels from 10-30, giving two distinct increases in risk from least to most polluted areas.

Every year 42,000 people in Britain are given a diagnosis of lung cancer, with smoking the main cause. "If you compare air pollution with smoking, it's very low risk - you can have a 3,000 per cent increase," Dr Raaschou-Nielsen said. "So it's not of that magnitude at all. At an individual level it's comparable to passive smoking."

He said it made sense for people to avoid clogged roads if possible, but that drastic measures such as moving house were not necessary. "If you can change your bicycle route so you don't cycle along busy roads, or avoid rush hour, then I would do it."

Chris Smyth
Source: The Times 10-07-2013
The Australian News