Outdoor air pollution is a leading environmental cause of cancer deaths, the World Health Organisation has revealed.
In a move that “should send a strong signal to the international community to take action without delay”, the global health body classified fresh air contaminated with pollutants as carcinogenic to humans.
WHO body the International Agency for Research on Cancer (IARC) listed the main sources of outdoor air pollution as transport, power generation, industrial and agricultural emissions, and heating and cooking in residential buildings.
The team said there was sufficient evidence that exposure to outdoor air pollution causes lung cancer.
It is also linked to an increased risk of bladder cancer. In 2010, 223,000 deaths from lung cancer worldwide resulted from air pollution, said IARC.
Particulate matter, a major component of outdoor air pollution, was evaluated separately and was also classified as carcinogenic to humans.
Researchers said that although the composition of air pollution and levels of exposure can vary dramatically between areas, their findings apply to all regions of the world.
IARC director Dr Christopher Wild said: “Classifying outdoor air pollution as carcinogenic to humans is an important step. 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 delay.”
Dr Kurt Straif, head of the IARC monographs section, said: “The air we breathe has become polluted with a mixture of cancer-causing substances.
“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.”
Dr Dana Loomis, deputy head of the monographs section, said: “Our task was to evaluate the air everyone breathes rather than focus on specific air pollutants. The results point in the same direction: the risk of developing lung cancer is significantly increased in people exposed to air pollution.”
Dr Julie Sharp, head of health information at Cancer Research UK, said: “It’s important that people keep the risk from air pollution in perspective.
“Although air pollution increases the risk of developing lung cancer by a small amount, other things have a much bigger effect on our risk, particularly smoking.
“The risk from air pollution depends on the levels of regular exposure.”
She added: “Cancer Research UK wants the government and relevant authorities to introduce measures that reduce air pollution to levels within EU limits to protect people’s health.”