Fog and Fireworks Trap Toxic Air Over England's Cities as Pollution Hits 'Very High' Levels

On Monday morning, the government's air quality monitors in parts of urban England were reading at the top of their scale. In the 24 hours to 10am, 11 monitoring sites, most of them in London and Greater Manchester, reached the highest band on the 10-point index for particulate matter. A further 27 sites logged "high" levels, spread across the capital, the north-west, the Midlands, Yorkshire and the east of England.

The worst reading came from Hillingdon, in west London. There, fine particles known as PM2.5 peaked at a 24-hour average of 129 micrograms per cubic metre, more than eight times the World Health Organization's daily guideline. In the north-west, Manchester Piccadilly, Wigan, Blackburn, Preston and Rochdale all landed in the "very high" band.

The cause was a combination of what people had set alight and what the weather refused to do. A weekend of fireworks and bonfires put particles into the air, and still, foggy conditions kept them near the ground. Particulate matter is made of tiny solid particles and liquid droplets suspended in the air, and exposure is linked to heart and lung disease and cancer.

Jane Burston, chief executive of the Clean Air Fund, noted that monitoring networks cannot say where pollution comes from, but she judged it highly likely that autumn celebrations were responsible. She pointed to the fog, the absence of wind, and the fireworks, bonfires and Diwali. Without wind, she said, the pollution is not blown away, and the fog holds it in place. For people with asthma or a lung condition, she said, going outside on Monday morning or Sunday would have been unwise, since the air can bring on attacks, coughing and wheezing. But she stressed the danger is not confined to them: people in the worst-affected areas, she said, were breathing particulate concentrations five to 10 times above normal annual levels.

Burston called for better pollution forecasts, more widely accessible health alerts, and stronger action on emissions from wood burning and transport. Her argument was that if air quality were far cleaner all year, an event like Bonfire Night would be less likely to push levels to extremes.

Larissa Lockwood, director of campaigns at Global Action Plan, said the readings were not surprising at a time of year when people light log burners, bonfires and fireworks. On top of normal emissions from transport and industry, she said, the extra pollution cannot disperse under fog. She identified domestic burning and transport as the biggest sources of particulate pollution, and called for a public health campaign and "burn alerts" that would ask people in towns and cities not to use wood burners when levels are high. She also urged a phase-out of non-essential burning in urban areas.

Official responses stressed the weather. A spokesperson for the mayor of London said that, on the advice of forecasters at Imperial College London, a high air pollution alert had been issued for Tuesday 10 November. Monitoring showed levels rising sharply across London from Friday to Sunday and staying elevated into Monday morning. Clean Air Greater Manchester said particulate levels rise every year around Bonfire Night, but that this year light winds and fog let pollution from many sources build up near ground level.

A Defra spokesperson said the still conditions were driving high levels in parts of the country, encouraged people to check local information and follow health advice, particularly the vulnerable, and said the department expects levels to fall later in the week as winds pick up. Until then, the London alert for Tuesday stands.