According to a new study, people who are exposed to high levels of certain air pollutants are at higher risk of developing an irregular heartbeat and blood clots in the lungweStreet/Flickr

Exposure to air pollution can cause lung cancer, according to a research conducted by the World Health Organization (WHO).

The International Agency for Research on Cancer (IARC), the specialised cancer agency of WHO located at Lyon in France, revealed on Thursday, its decision to classify outdoor air pollution, including particulate matter (a component of air pollution) as carcinogenic to humans. "The air we breathe has become polluted with a mixture of cancer-causing substances," Dr Kurt Straif, Head of the IARC Monographs Section, said in a news release. "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."

Researchers from the agency reviewed more than 1,000 scientific studies from five continents that focussed on the link between air pollution and cancer. Air pollution was mainly caused by transportation, industrial and agricultural emissions, residential heating, cooking and stationary power generation.

They found that air pollution caused lung cancer and played a major role in increasing the risk of bladder cancer. In 2010, lung cancer caused by air pollution claimed nearly 2,23,000 lives across the world.

They said that air pollution had considerably increased in the recent past due to industrialisation, and added that it can also contribute to the development of deadly diseases including heart and respiratory diseases. "Classifying outdoor air pollution as carcinogenic to humans is an important step," IARC Director Dr Christopher Wild, said. "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."

The findings will be published in The Lancet Oncology.

Last year, the agency had classified diesel engine exhaust as carcinogenic to humans.

The risks posed by air pollution have been a hot topic for a very long time. Previous studies have linked exposure to air pollution during pregnancy to a wide range of diseases, including asthma, autism and vitamin D deficiency in children and maternal pre-eclampsia (a condition that triggers hypertension).

According to health experts, exposure to particles in the air or pollutant ozone (O3) can cause cancer, early death, reproductive and cardiovascular problems and damage central nervous system.