THE worst air pollution in 60 years is set to sweep through parts of the South 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.
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.
In the Ryedale area, the weather forecast today is for cloudy and cool conditions with mist and fog affecting higher and coastal areas. The pollution levels in this area area expected to be low.
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."