Air pollution classified as a leading cause of cancer

World Health Organisation agency officially classifies air pollution as human carcinogenic after links found to lung cancer and bladder cancer

Outdoor air pollution is a leading environmental cause of cancer deaths, according to the World Health Organisation (WHO), which has officially classified it as carcinogenic to humans.

The International Agency for Research on Cancer (IARC), a specialised agency of the WHO, found that exposure to air pollution causes lung cancer and also has a positive association with an increased risk of bladder cancer.

The World Health Organisation has classified air pollution as human carcinogenic

Particulate matter, evaluated separately to outdoor air pollution, was also classified as carcinogenic to humans.

The announcement was made yesterday (October 17) after research was conducted by the IARC’s monographs programme — also known as the ‘encyclopaedia of carcinogens’ — which compiles scientific evidence on cancer-causing substances and exposures.

It follows the publication on October 7 2013 of the IARC’s ‘Air Pollution and Cancer’ e-book, which contained recent estimates that exposure to ambient fine particles contributed to 3.2 million premature deaths worldwide in 2010.

This, the publication said, was largely due to cardiovascular disease, as well as 223,000 deaths from lung cancer. More than half of the lung cancer deaths attributable to ambient fine particles were projected to have been in China and other East Asian countries.

Lead author of the publication and head of the IARC monographs section, Dr Kurt Straif, 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 monographs programme has previously evaluated various individual chemicals and specific mixtures that occur in outdoor air pollution, such as diesel engine exhaust, solvents, metals and dusts. However, the IARC claims this is the first time that scientists have classified outdoor air pollution as a cause of cancer.

Important step

Deputy head of the monographs section, Dr Dana Loomis, said: “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 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 monographs programme’s air pollution study was based on the independent review of more than 1,000 scientific studies on five continents, analysing the carcinogenicity of various air pollutants — especially particulate matter and transport-related pollutants.

According to the IARC, the predominant sources of outdoor air pollution are transportation, stationary power generation, industrial and agricultural emissions, and residential heating and cooking. Some air pollutants also have natural sources.

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 further delay.”