Air pollution causes cancer, according to a new report issued by the World Health Organization.
The report said there is sufficient evidence that exposure to outdoor air pollution causes lung cancer. The report also associated bladder cancer with air pollution.
It is the first time that experts have classified outdoor air pollution as a cause of cancer.
“The air we breathe has become polluted with a mixture of cancer-causing substances,” says Kurt Straif, Head of World Health’s International Agency for Research on Cancer Monographs Section. “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.”
The report also cited particulate matter, a major component of air pollution that was evaluated separately, as a carcinogen associated with an increased risk of lung cancer. The report said that while the composition of air pollution and levels of exposure can vary depending on location, the conclusions apply to all regions of the world.
The conclusions were reached after an independent review of more than 1,000 scientific papers from studies on five continents. The reviewed studies analyze the carcinogenicity of various pollutants present in outdoor air pollution, especially particulate matter and transportation-related pollution.
The predominant sources of outdoor air pollution are transportation, stationary power generation, industrial and agricultural emissions, and residential heating and cooking. Some air pollutants have natural sources as well.
Air pollution has already been linked to respiratory and heart diseases, but as levels rise, particularly in rapidly industrializing countries with large populations, more people are being exposed.
World Health said that in 2010 there were 223,000 deaths worldwide from lung cancer caused by air pollution.
“Our task was to evaluate the air everyone breathes rather than focus on specific air pollutants,” said Dr. Dana Loomis, Deputy Head of the Monographs Section. “The results from the reviewed studies point in the same direction: the risk of developing lung cancer is significantly increased in people exposed to air pollution.”