Dr Maria Neira, director of environment, climate change and health at WHO.
WHO’s new global air quality guidelines remind us that much of what we think of as environmental policy is actually health policy. They pull health back into the heart of discussions on air quality and prompt the question, “how much risk of damage to the electorate’s health from air pollution are we willing to live with, given what we now know?”
More is known about the deadly effects of air pollutants
It’s an increasingly tight calculation. The new guidelines recommend more stringent limits to the levels of five out of the six pollutants of worldwide importance, PM2.5, PM10, ozone, nitrogen dioxide and carbon monoxide. Sulphur dioxide was the only pollutant whose recommended limit was relaxed.
The annual average limit for the most-deadly of them all, PM2.5, was halved. This particulate matter is so microscopic, it breaches all manner of barriers between systems in the body, and may even carry toxic substances with it, generating an inflammatory response. And nitrogen dioxide limits are four times as stringent as they were in the 2005 guidelines.
The new guidelines are the result of a rigorous, lengthy expert review process based on a body of evidence that has expanded significantly in the 15 years since they were last published. They show the damage air pollution inflicts on human health, at much lower levels than was previously known.
Getting PM2.5 alone down to the guideline level globally would cut deaths from air pollution by 80 per cent. For perspective, seven million people globally die early each year from diseases caused or exacerbated by exposure to air pollution; in the UK, the figure is 28,000 to 36,000 people (from the Committee on the Medical Effects of Air Pollutants).
Policy makers vary in their willingness to act
Many countries have incorporated the 2005 guidelines into their air quality legislation, but gaps exist between the guideline levels and the standards adopted in national regulations.
While WHO’s guidelines are evidence based health recommendations, the process of developing legally binding regulations is driven by national and local policy makers, who differ in their willingness to set standards. By choosing higher limit values for ambient concentrations of regulated pollutants than WHO recommended levels, legislators are accepting higher risks to health caused by the pollution, on behalf of their electorate.
Naturally, the WHO calls on countries to use this resource to implement effective policies to reduce air pollution, ease the burden of disease, create healthy communities and save lives. As many pioneering governments have discovered (London among them), this requires the existence and operation of air pollution monitoring systems, public access to air quality data, legally binding, globally harmonised, air quality standards and air quality management systems.
It also requires a whole government approach, the co-operation of all economic sectors and stakeholders, and an end to siloed thinking. If we value health, it should not be an externality in policy. The health sector’s involvement is also crucial to raise awareness of air pollution’s impacts, including on the economy, ensuring that protecting health is central to policy discussions.
National policies and legislation that set, monitor and enforce targets and standards, incorporating WHO guidelines, demonstrate political commitment that is valuable for planning. It serves to trigger or ripen innovation. More crucially, it avoids decisions that inadvertently lead to actions that cause or lock in air pollution.
Failing to manage the problem has huge costs
The cost of mismanaging this has been staggering. Between 2017 and 2025, Public Health England estimated the cost to the NHS and social care from exposure to PM2.5 and nitrogen dioxide, in England alone, was £1.6 billion. A less conservative estimate, which included diseases for which the evidence is less robust or emerging, placed that figure at £5.56 billion. And the Royal College of Physicians has modelled the cost to whole of the UK at over £20 billion annually.
At the global level, the World Bank’s 2013 Global burden of disease estimated an economic impact of over US$140 billion in lost labour income, and over US$3.5 trillion in human health costs associated with exposure to PM2.5 alone. On the flip side, the CBI has estimated that a £1.6 billion annual economic benefit to the UK could be realised by meeting WHO guidelines.
Improving air quality is good for the climate too
The guidelines have been published in good time to inform to the world’s efforts to build forward better as it emerges from Covid-19. The pandemic has been a tragedy but, as response measures kicked in, many people saw the sky, mountains and buildings around the world as they have never seen them before, without pollution. It gave them a glimpse of the possible. Covid-19 has also reminded us of the extra vulnerability bad air quality confers on us, with underlying illnesses caused or exacerbated by exposure to air pollution making severe illness and death from the virus more likely.
These guidelines are also timely as we approach COP26 in Glasgow, which will continue to develop the mechanisms and processes to fulfil the aims of the Paris Agreement on climate change. Actions that benefit air quality help to mitigate climate change, and vice versa, as certain air pollutants that have negative health impacts are also strong drivers of climate change.
Clean air is a human right
The right to a healthy environment, including clean air, was recently declared a human right by the UN Human Rights Council, on which the UK sits. The Sustainable Development Goals, whose deadline is just nine years away, call for the reduction of air pollution exposure. In 2015, ministries of health committed to a World Health Assembly resolution to reduce or avoid air pollution exposure and facilitate relevant research, along with strengthening multisector co-operation and taking effective steps to reduce health inequities related to air pollution.
Ultimately, although they are robust and thorough, these guidelines are only guidelines. The onus is now on politicians to use them and take action to reduce exposure to air pollution and its health burdens. In the UK, it is the chance to make a healthier, cleaner future part of the post-Brexit legacy. As we reach the final stages of the Environment Bill’s progress through parliament, the government has a timely opportunity to demonstrate global leadership by embedding in law an ambitious approach to air pollution. And the time is right, as understanding of the impacts of air quality and climate change, which is now part of mainstream consciousness, is only set to grow.