Air pollution’s role as a cause of cancer has slowly been shifting to the centre stage over the past few years.

Over the past decades evidence that air pollution is linked to a range of cancers has been mounting. In 2013, a group of international experts, working on behalf of the World Health Organisation’s International Agency for Research on Cancer (IARC), looked at the results of all of the research and concluded that air pollution causes cancer in humans – in particular, lung cancer.

Outdoor pollution.

But what do these experts mean by ‘air pollution’? The term is very broad, and covers a host of ‘nasties’ including minuscule particles, tiny fragments of metals and gases. But when it comes to cancer risk, research so far shows that tiny dust-like particles just millionths of a metre wide – so called ‘particulate matter’, or PM – are the main culprit. In particular, the smallest particles – less than 2.5 millionths of a metre across, known as PM2.5 – appear to be behind lung cancers caused by pollution. These are chiefly found in emissions from diesel engines – something IARC have also ruled causes cancer in humans.

Indoor pollution.

Quite often when a non-smoker homemaker gets cancer, all wonder why! There are severe pollutants indoor as well. Though use of coal and wood for cooking has come down, we still use cooking gas. Though there is no evidence at present that cooking gas can cause cancer, it is a fossil fuel. Burning any fossil fuel releases fine particulate matter that are harmful. What is recommended is to cook in well ventilated kitchen.

This emphasises the need for a better understanding of the actual risk of cancer posed by environmental factors, and of the effect of measurements aimed at controlling exposure to environmental carcinogens.