The smog that has blanketed Britain this week is likely to lift during the next day or so, Al Jazeera's senior meteorologist has said.
Everton Fox said Britons could look forward to an improvement by late Thursday.
"Areas of low pressure from the Atlantic are already starting to push the Sirocco [Saharan] winds from North Africa further east," Fox said.
A combination of local emissions, light winds and pollution from continental Europe, compounded with dust blown across from the Sahara, have prompted health warnings about poor air quality across southern and central England.
Data from Britain's environment ministry showed pollution levels were "very high" - 10 on a scale of 10 - in London and nine in parts of eastern England on Thursday morning.
British authorities warned people with heart or lung conditions to stay indoors, as motorists woke to find their cars covered in a film of red dust.
The smog comes just weeks after Paris was forced to resort to drastic measures to curb soaring pollution levels for the first time in two decades by forcing cars with number plates ending in even or odd numbers off the road.
The pollution levels were more than double the safe limit in the French capital, having been created by vehicles, heating and heavy industry.
Fox said the British event was not unprecedented and "happened once every five to 10 years".
Source: Al Jazeera and agencies