“No one at the time thought of the consequences of increased nitrogen dioxide emissions from diesel, and the policy of incentivizing diesel was so successful that an awful lot of people bought diesel cars,” said Anna Heslop, a lawyer at ClientEarth, an environmental law firm that last year forced the British government to produce a better plan to improve air quality.
Air pollution is a more significant public health hazard in China, India and Eastern Europe, where the average annual levels of PM2.5 pollution, the fine soot particles and molecules that pose the greatest danger to health, are up to 10 times as high as in London.
But in mid-January in Brixton, the area in south London where Ms. Carey lives, hourly mean levels of PM2.5 were higher than in Beijing. And over just five days in January, Brixton exceeded the European Union’s nitrogen dioxide legal limit for the entire year.
London last month was put on a “very high” pollution alert for the first time ever, as cold air and a stationary weather pattern failed to clear the toxic air caused by diesel traffic, as well as by the high use of open fires, which contribute to about 10 percent of pollutants in winter months.
“The time will come when we’ll start wearing masks like in China,” Ray Hussain, 73, said as he waited for his bus on Brixton Road one recent morning. At nearly any point during the rush, 16 double-decker buses lined the road. Traffic was snarled, and whiffs of acrid air stung the eyes.
Mr. Hussain checked Airvisual, an air pollution tracking app on his smartphone. Brixton’s air quality that day was called “Good,” in green lettering. Just below, Hyderabad, a city in India, had a red “Unhealthy” label and a picture of a person wearing a face mask.
The local authorities are scrambling to defuse what many consider a ticking time bomb for public health.
Some schools are considering handing out gas masks to pupils, saying children’s lungs are in danger of being stunted. More than 440 schools are in areas exceeding legal air quality levels, according to Mayor Sadiq Khan of London.
Earlier this month, London’s Metropolitan Police announced a plan to introduce about 300 environmentally friendly cars, including hydrogen fuel cell vehicles and hybrid electric cars, as part of a fleet overhaul.
On Friday, Mr. Khan, who has adult-onset asthma, announced that in October he would introduce in central London a toxicity charge, a $12-a-day tax for the most polluting vehicles, typically diesel- and gasoline-powered automobiles registered before 2006.