New research has indicated that air pollution may have a larger role than previously thought in directly causing lung cancer.
Scientists at the Crick Institute, conducting work funded by Cancer Research UK, have produced evidence that exposure to high levels of particulate matter (PM2.5) contained in urban air pollution can trigger the growth of genetic mutation-carrying cells in the lungs. This helps explain how some people can still get lung cancer even if they have never smoked.
The study of data from over 400,000 people found that other cancers also appear more likely to occur among those exposed to high levels of PM2.5, which suggests the risks are greater for people living in urban areas with lower air quality.
Around one in ten UK lung cancer cases occur as a result of air pollution, which contributes to 6,000 deaths from the disease among non-smokers every year. Exposure to PM2.5 is estimated to have caused 300,000 lung cancer deaths around the world in 2019.
Lead investigator in the study Professor Charles Swanton said the study had “fundamentally changed” how people who have never smoked but get lung cancer are viewed.
He noted: “Cells with cancer-causing mutations accumulate naturally as we age, but they are normally inactive,” but added that the research has “demonstrated that air pollution wakes these cells up in the lungs, encouraging them to grow and potentially form tumours”.
Professor Swanton said if a way can be found to stop cancerous cells growing in response to air pollution, this would reduce cases.
The knowledge of the link may also help with early diagnosis and treatment, if people who live in areas with high air pollution are tested more regularly.
According to government figures, the highest levels of PM2.5 are in London, the south east and south west, but levels across the UK have been falling since 2010.