UNITED NATIONS, Oct 18: The specialised cancer agency of World Health Organisation (WHO) has said that outdoor air pollution is a leading environmental cause of cancer deaths.

According to the International Agency for Research on Cancer (IARC), there is sufficient evidence that exposure to outdoor air pollution causes lung cancer and increases the risk for bladder cancer.

The IARC points out in a statement that air pollution is already known to increase risks for a wide range of diseases, such as respiratory and heart diseases. Studies indicate that in recent years exposure levels have increased significantly in some parts of the world, particularly in rapidly industrialising countries with large populations.

The most recent data indicate that 223,000 deaths from lung cancer in 2010 were caused by air pollution.

“The air we breathe has become polluted with a mixture of cancer-causing substances,” said Kurt Straif, head of the IARC’s 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.”

The IARC’s Monographs Programme, dubbed the “encyclopaedia of carcinogens,” provides an authoritative source of scientific evidence on cancer-causing substances and exposures. In the past, the programme evaluated many individual chemicals and specific mixtures that occur in outdoor air pollution. These included diesel engine exhaust, solvents, metals, and dust. But this is the first time that experts have classified outdoor air pollution as a cause of cancer.

“Our task was to evaluate the air everyone breathes rather than focus on specific air pollutants,” said Dana Loomis, deputy head of the 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 main sources of outdoor air pollution are transportation, stationary power generation, industrial and agricultural emissions, and residential heating and cooking. Some air pollutants have natural sources, as well.

“Classifying outdoor air pollution as carcinogenic to humans is an important step,” stressed IARC’s 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.”—APP