It's Official: Air Pollution Causes Cancer

What many commuters choking on smog have long suspected has finally been scientifically validated: air pollution causes lung cancer. The International Agency for Research on Cancer declared today that air pollution is a carcinogen, alongside known dangers such as asbestos, tobacco, and ultraviolet radiation. The decision came after a consultation by an expert panel organized by IARC, the cancer agency of the World Health Organization, which is based in Lyon, France.

"The air most people breathe has become polluted with a complicated mixture of cancer-causing substances," said Kurt Straif, head of the IARC department that evaluates carcinogens. He said the agency now considers pollution to be "the most important environmental carcinogen," ahead of second-hand cigarette and cigar smoke. IARC had previously deemed some of the components in air pollution such as diesel fumes to be carcinogens, but this is the first time it has classified air pollution in its entirety as cancer causing. (More cancer stories.)