Air pollution can cause lung cancer in people who have never smoked by “waking up” dormant cancer cells, scientists have found.

UK researchers have uncovered the mechanism by which tiny pollution particles help cells with cancer-causing mutations grow.

The team said its findings, published in the journal Nature, could help develop new treatments for non-smokers diagnosed with lung cancer.

Professor Charles Swanton, of the Francis Crick Institute and UCL and Cancer Research UK chief clinician, who is lead investigator on the study, said: “Our study has fundamentally changed how we view lung cancer in people who have never smoked.

“Cells with cancer-causing mutations accumulate naturally as we age, but they are normally inactive.

“We’ve demonstrated that air pollution wakes these cells up in the lungs, encouraging them to grow and potentially form tumours.

“The mechanism we’ve identified could ultimately help us to find better ways to prevent and treat lung cancer in never-smokers.

“If we can stop cells from growing in response to air pollution, we can reduce the risk of lung cancer.”

While smoking remains the biggest risk factor for lung cancer, it is estimated that nearly 6,000 people who have never smoked die of lung cancer in the UK each year.

As part of the study, which received £14 million in funding from Cancer Research UK, the scientists examined data from more than 400,000 people from the UK, South Korea, and Taiwan.

They focused on a type of lung cancer that is caused by a mutation in the EGFR gene.

Known as epidermal growth factor receptor (EGFR) mutant lung cancer, it is commonly found in people who have never smoked.

Tests on mice showed PM2.5 particles promoted rapid changes in airway cells which had EGFR mutations.

Commenting on the research, Sarah Woolnough, chief executive of Asthma + Lung UK, said: “This important research is further evidence of air pollution having a role in causing lung cancer, the deadliest cancer in the UK, in non-smokers.

“It also helps us to challenge and change attitudes around lung cancer, that only smokers can get this debilitating disease.

“The truth is, air pollution affects everyone’s lungs and is responsible for worsening existing lung conditions and creating new ones in healthy people.

“Up to now the Government has failed to match the ambition that’s needed to tackle this problem.

“We need to see bold action, including plans to get the most polluting vehicles off our roads, if we are to reduce toxic air and protect people’s health.”