Depending on where you're reading this, the air you're breathing could be giving you cancer.
Outdoor air – not any one contaminant in particular – is "the most widespread environmental carcinogen," according to a brand-new report from the World Health Organization's International Agency for Research on Cancer. "The air we breathe has become polluted with a mixture of cancer-causing substances," Dr. Kurt Straif, head of the IARC Monographs Section, said in a press release [PDF]. "We now know that outdoor air pollution is not only a major risk to health in general, but also a leading environmental cause of cancer deaths." Remarkably, it now ranks ahead of second-hand tobacco smoke as a danger.
Some 223,000 lung cancer deaths around the world in 2010 could be attributed to air pollution, according to the report. There is also "a positive association with an increased risk of bladder cancer."
Unlike a smoking habit, air pollution is something that people – especially residents of urban areas – cannot avoid by choice. Nor can they easily pay their way out of cancer risk, as consumers of organic produce do in more affluent communities.
The air we breathe is inescapable. For residents of a city like Beijing, where this week pollution levels reached 40 times the level deemed safe by WHO, the immediate effects of high particulate and ozone readings are simply a part of life.
As the now-routine smog season in northern China got underway earlier this month, schools were closed, highways were shut down, and flights diverted as visibility shrank to 50 yards. American jazz singer Patti Austin had to cancel a concert in Beijing due to a severe asthma attack and respiratory infection, according to press reports.
IARC officials acknowledged that exposure to air pollution is greater in rapidly industrializing nations such as China and India. But they emphasized that this is a global problem. "Our conclusion is that this is a leading environmental cause of cancer deaths," IARC director Dr. Christopher Wild told reporters at a briefing on the report.
"There are effective ways to reduce air pollution and, given the scale of the exposure affecting people worldwide, this report should send a strong signal to the international community to take action without further delay," Wild said in a statement.
Reducing the use of coal to produce electricity and curbing emissions from vehicles are two actions that governments such as China’s have vowed to undertake. But the gains have yet to be realized. Meanwhile, the residents of the world’s cities – many of them dangerously and chronically polluted – have to keep breathing.