Outdoor air pollution and particulate matter (a major component of outdoor air pollution), were deemed to be carcinogenic to humans by the World Health Organization’s International Agency for Research on Cancer (IARC), according to research in The Lancet Oncology. This marks the first time that experts have classified outdoor air pollution (in its entirety) as a cause of cancer, according to the IARC. Until now, only components of outdoor air pollution were deemed carcinogens.

“Our task was to evaluate the air everyone breathes rather than focus on specific air pollutants,” explains Dana Loomis, MSPH, PhD, deputy head of the IARC’s 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.”

The IARC evaluation showed an increasing risk of lung cancer with increasing levels of exposure to particulate matter and air pollution. Although the composition of air pollution and levels of exposure can vary dramatically between locations, the conclusions of the working group apply to all regions of the world. The most recent data indicated that in 2010, 223,000 deaths from lung cancer worldwide resulted from air pollution, according to the IARC.

“Classifying outdoor air pollution as carcinogenic to humans is an important step,” said IARC Director Christopher Wild. “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.”