Sahara dust brings smog to Britain


European pollution and dust swirling in from the Sahara created a “perfect storm” of smog in Britain on Wednesday, prompting authorities to warn people with heart or lung conditions to cut down on tough physical exercise outdoors.

Air pollution in some areas reached the top rung on its 10-point scale, the environment department said.

The smog was caused by pollution from Britain and industrialized areas of the Continent — trapped in place due to light winds — mixing with dust blown up from a storm in the Sahara Desert.

Many motorists across England awoke this week to find cars covered in a film of red dust left by overnight rain.

Cars outside Prime Minister David Cameron’s Downing Street residence have been covered with dust blown in from the desert 2,000 miles (3,200 kilometers) to the south, and the offices of some of the world’s biggest banks faded into the haze in east London’s Canary Wharf.

Dust was thrown up by sandstorms in northwest Africa at the end of March and deposited in rains, the Met Office said.

Paul Cosford of Public Health England told the BBC that people with heart or respiratory problems should “reduce the amount of strenuous exercise outdoors.”

An unusual combination of factors had conspired “to create a ‘perfect storm’ for air pollution,” according to Helen Dacre, a meteorologist at the University of Reading.

“Toxic gases, such as nitrogen dioxide and ozone, as well as fine dust particles in the air blown in from the Sahara and from burning fossil fuels, all contribute to cause problems for people with heart, lung and breathing problems, such as asthma,” she said.

Laura Young, a Met Office spokeswoman, said: “Most of this week, we’ve had very light winds, which has allowed local pollutants to build up. The little wind we have had has been coming from east and southeast, bringing particles from across the channel. Add to that some Sahara dust.”

“There’s not much we can do to control dust from the Sahara, but the authorities could and should be doing far more to deal with the U.K.’s contribution to this air-pollution episode, particularly from road traffic emissions,” said Jenny Bates, a campaigner at environmental pressure group Friends of the Earth, in an emailed statement.

Despite efforts to make industry and automobiles cleaner, air pollution remains a major problem in Britain and across Europe.

Last month, Paris took the drastic step of banning half the city’s cars from the roads for a day after a week in which pollution levels exceeded those in notoriously smoggy cities including Beijing and Delhi.