Air Pollution: The Most Widespread Environmental Carcinogen

By Roberta Attanasio

Exposure to outdoor air pollution causes lung cancer in humans – this is the conclusion drawn by leading experts after thoroughly reviewing the latest available scientific literature.  The same experts evaluated particulate matter separately and reached a similar conclusion. Therefore, particulate matter is now classified as carcinogenic to humans. These conclusions apply to all regions of the world as they are based on findings from large epidemiologic studies that include millions of people living in different continents.

The experts were convened by the IARC Monographs Programme. IARC (International Agency for Research on Cancer) is the specialized cancer agency of the World Health Organization (WHO). The IARC Monographs identify environmental factors that can increase the risk of human cancer. These factors include chemicals, complex mixtures, occupational exposures, physical agents, biological agents, and lifestyle factors. National health agencies can use such information as scientific support for their actions to prevent exposure to potential carcinogens.

The IARC Monographs Programme announced the findings related to air pollution, particulate matter and human cancer on October 17, 2013. Both air pollution and particulate matter are now considered Group 1 carcinogens. The Group 1 category is used when there is sufficient evidence of carcinogenicity in humans.

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.”

The major sources of air pollution across the globe are emissions from motor vehicles, industrial processes, power generation and household combustion of solid fuel. The precise chemical and physical features of air pollution, which comprises a myriad of individual chemical constituents, vary around the world due to differences in the sources of pollution, climate, and meteorology, but the mixtures of ambient air pollution invariably contain specific chemicals known to be carcinogenic to humans.

The disease burden due to air pollution is substantial, with millions of death caused by cardiovascular disease. According to “Air Pollution and Cancer”, IARC Scientific Publication No. 161, the most recent data indicate that in 2010, air pollution caused 223,000 deaths from lung cancer worldwide.

Dr. Christopher Wild, IARC Director, 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 further delay.”

Don’t forget: You can help keep the air cleaner — every day!