Out of 51 UK cities and towns listed in an air quality database, 44 fail the WHO’s test for fine sooty particles smaller than 2.5 microns across that have been linked to heart disease, stroke, cancer and premature death.
Exposure to the particles, known as PM2.5s, should not exceed 10 micrograms per cubic metre of air, according to the United Nations agency.
But in numerous British population centres annual average levels are higher, sometimes by a significant degree, it is claimed.
Glasgow has emerged as one of the most polluted cities in the country, with a PM2.5s concentration of 16 micrograms per cubic metre.
The seaside town of Prestonpans in East Lothian also had dangerously high levels, with 12 micrograms per cubic metre – higher than in cities such as Aberdeen, Edinburgh and Inverness.
London and Leeds both had 15 micrograms of the particles in every cubic metre-sized parcel of air, while Cardiff, Oxford and Birmingham had 14 and Manchester 13.
Each year, outdoor air pollution is estimated to cause 40,000 premature deaths across the UK – 2,500 of them in Scotland alone – and costs the country £22.6 billion.
Report author Dr Toby Hillman, from the Royal College of Physicians, said: “There isn’t a safe limit for the amount of pollution that’s been defined as yet and we know the effects of poor air quality run from cradle to grave; it’s a lifetime threat to human health.
“This is a really direct and tangible impact on UK health from the drivers of climate change, and taking action on air quality should be a priority.”
The impact of air pollution in UK cities forms part of a major investigation looking at the health and social costs of climate change around the world led by a top medical journal.
The Lancet Countdown on Health and Climate Change brought together 24 institutions and inter-governmental organisations, including the WHO and World Meteorological Organisation.
It found that global exposure to dangerous levels of air pollution caused by burning fossil fuels had increased by 11.2 per cent since 1990, with more than 70 per cent of cities exceeding WHO PM2.5 limits.
Many British cities and towns also broke the WHO limits for the slightly larger PM10s, which are harmful to health but less so than ultra-fine particles.
The authors acknowledged that European Union air quality guidelines were far less stringent than those of the WHO, with an upper safety limit for PM2.5s of 25 micrograms per cubic metre. However, they claim WHO limits represent a “safer threshold”.