What they have found is that unlike many environmental agents such as UV light and tobacco smoke, there has never been biological evidence that particulate matter directly mutates DNA, which doesn’t explain why air pollution has been linked to cancer. So fresh research based on new assumptions has shown that it is the inflammation caused by air pollution (and in particular PM2.5 which is the classification of tiny particles about 3% the width of a human hair) that stimulates dormant cancer-carrying cells and triggers them into uncontrollable tumour-forming growth.

This finding has excited cancer research teams the world over as it could lead to explanations of how the many so-called cancer-causing substances are actually acting on the body and thereby paving the way for a new wave of cancer-preventing medicines.

Leading expert, Professor Charles Swanton, clinician scientist at the Francis Crick Institute in London and lead investigator for the Cancer Research funded TRACERx Lung Study, explains that their view now is that air pollution wakes up old damaged cells rather than causes the damage and that the breakthrough marks a new era.

He says, “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. The next step is to discover why some lung cells with mutations become cancerous when exposed to pollutants while others don’t. If we can stop cells from growing in response to air pollution, we can reduce the risk of lung cancer.”

Speaking at ESMO Congress 2022 in Paris earlier this month, Professor Swanton highlights the impact that air pollution is having on human health globally and, whilst the toxic chemicals in cigarette smoke are more directly damaging, far more people are exposed to unsafe and uncontrolled levels of air pollution. His emphasis was strongly on the importance of addressing the air pollution issue in order to secure a future of better health.

Potentially, this is not only affecting lung cancer; examining data from over 400,000 people has exposed higher rates of other types of cancer in areas with high levels of PM2.5 suggesting that air pollution promotes the growth of cells carrying cancer-causing mutations elsewhere in the body.

Dr Emilia Lim, postdoctoral researcher at the Francis Crick Institute and UCL, says, "This finding suggests a broader role for cancers caused by inflammation triggered by a carcinogen like air pollution. Even small changes in air pollution levels can affect human health. 99% of the world’s population lives in areas which exceed annual WHO limits for PM2.5, underlining the public health challenges posed by air pollution across the globe."

Dr William Hill, postdoctoral researcher at the Francis Crick Institute, says, “Air pollution needs to wake up the right cells, at the right time, for lung cancer to start and grow. EGFR mutations are an essential step towards cancer forming, but they are rare, affecting around 1 in 600,000 cells in the lung. These rare cells are dormant until a trigger, such as air pollution, causes them to start growing. 

“The mechanism we’ve identified may explain why there is an increased risk of cancer from air pollution, but the risk is much lower compared to smoking, which mutates DNA directly. Finding ways to block or reduce inflammation caused by air pollution would go a long way to reducing the risk of lung cancer in people who have never smoked, as well as urgently reducing people’s overall exposure to air pollution.”

Interestingly, whilst this research work has been going on, an international science consortium has been agreeing on and issuing powerful statements declaring that clean air is no longer a policy objective on every country's wish list; it is simply and irrevocably a fundamental human right. Air pollution on today’s scale clearly violates the rights to life and health, the rights of the child, and the right to live in a safe, clean, healthy and sustainable environment.

This is taking the issues to a whole new level and is putting intense pressure on the world's governments who have legally enforceable obligations to respect, protect, and fulfil human rights.

With over ninety percent of the global population living in regions of high air pollution, exceeding the standards set out by the World Health Organisation, it is hardly surprising that the very worst air quality is found in homes where solid fuels are used for cooking and heating. It's in these situations where women and children in particular are exposed to air pollution in the supposed safety of their own homes at levels far higher than found in even the world’s most smog-ravaged cities.

So, what are the likely consequences of recognizing that everyone, everywhere has the right to breathe clean air?

Well, certainly in the UK it has sparked off the Clean Air (Human Rights) Bill which has had its first and second readings in the Lords and is currently at Committee stage. Introduced as a private member’s bill by Baroness Jones of Moulsecoomb, this is a completely fresh perspective applied to the whole issue of air quality that has been previously addressed in the Clean Air Acts of 1956, 1968 and 1993 and the Environment Act of 2021. It means that the key driver is the objective; as Stephen Covey so famously said, Begin with the end in mind.

Jones said: “Having a nice environment isn’t just a matter of ecology and science, it is a question of social justice. The Clean Air (Human Rights) Bill would enshrine the human right to healthy air precisely and explicitly in UK law. A suitable date for the government to put it into law would be before the 70th anniversary of the Great Smog later this year”.

The Great Smog refers to a week-long period of dense smog in London in 1952, which directly accounted for the lives of about 4,000 people. Compare this with the death rates of the Victorian cholera period, when many thousands of lives were lost over a number of years, and the worst period of the blitz when over 1,400 London civilians were killed in two days, and it brings this figure of 4,000 lives in one week into stark relief. MP Gerald Nabarro took this up in a private member’s bill and in 1956, which became law later that year.

Then again, in December 1957, 4 days of intense fog saw smoke and sulphur dioxide concentrations reaching levels comparable to 1952 resulting in nearly 1,000 deaths, and a further 750 deaths directly as a result of a similar occurrence in 1962. Today, it is reckoned that about 4,000 Londoners die from breathing polluted air each year; similarly, annual UK deaths are around 30,000 and globally, 7 million.

Dr Maria Neira, the World Health Organisation (WHO) director for public health, environmental and social determinants of health, said: “These days we have overwhelming evidence that air pollution harms health, more than enough evidence to justify actions to reduce exposure. You can imagine the incredible number of lives we will save.”

In summary, whilst we have known that air pollution is bad for health and causes cancer, from recent discoveries it is highly likely that it is not the source of the cancer but the trigger of a pre-existing state. This now puts the whole pharma and medical products world on their mettle to be able to come up with new treatments in response to these groundbreaking discoveries.