THE worst air pollution in 60 years is set to sweep through parts of Essex tomorrow threatening the health of the sick and vulnerable.
Defra has warned people to be braced for "very high" levels of air pollution over the next few days.
The East of England, including parts of Essex, are among the worst-affected areas, but large swathes of England and Wales will see high levels of pollution, the Department for Environment, Food and Rural Affairs has said.
The elevated pollution levels have been caused by a combination of light south-easterly winds, the continental air flow and dust which has blown up from the Sahara desert, a spokeswoman said.
Westcliff GP, Dr Marimuthu Velmurugan, has warned people with asthma to wear a mask if they venture outside.
He said: "Anyone with asthma or a chronic airway disease should wear a mask if they are going outside. But people should try to stay indoors, especially during daylight."
The Defra forecast added: "The current elevated pollution levels over parts of the UK are caused by light winds allowing the build-up of pollution, plus dust from the Sahara contributing to pollution levels."
The high levels of pollution are expected to continue across East Anglia and the Midlands on Thursday.
But the air pollution is expected to ebb away by Friday.
However, people with heart and lung conditions have been warned to avoid strenuous activity.
This week people found their cars to be covered in a light coating of red dust. The Met Office said that a large amount of sand and dust was swept up by storm winds in the Sahara Desert.
Experts said that the airborne particles of dust were blown north to the UK where they combined with our warm air and were deposited during showers.
A Defra spokeswoman said: "The high level of air pollution this week is due to a combination of local emissions, light winds, pollution from the continent and dust blown over from the Sahara.
"We want to keep improving air quality and have introduced a new five-day forecast service in addition to investing heavily in local and transport initiatives to tackle this issue head-on."