PHILADELPHIA (CBS) – It seems like everything causes cancer these days, including, apparently, the air we breathe.

According to new research from the International Agency for Research on Cancer, outdoor air pollution has now been categorized as carcinogenic to humans. Particulate matter, defined by the EPA as “a complex mixture of extremely small particles and liquid droplets,” has been given the same designation.

While this probably comes as a surprise to no one, the IARC says information from five continents now provides sufficient evidence that exposure to outdoor air pollution causes lung cancer and is associated with a higher risk of bladder cancer. The organization tells Reuters that the delay in verifying the link is largely due to the lag between exposure and the onset of cancer.

“The air we breathe has become polluted with a mixture of cancer-causing substances,” says Dr Kurt Straif, Head of the IARC 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.”

In other words, some of us are literally inhaling poison – Philadelphia was ranked the 11th most polluted city in 2013.

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