Levels of air pollution are forecast to become HIGH in many areas of central, eastern and northern England tomorrow.
This situation has been caused by a combination of pollutants trapped near the ground, a light southeasterly flow bringing additional pollutants from the continent and, in addition, a small amount of Saharan dust in the air.
The good news is a change in wind direction overnight into Saturday will clear the 'dirty' air out the way.
Air pollution levels will be moderate to high for many parts over the next couple of days.
But fresher air from the west will soon cleanse the atmosphere - bringing fresher air in from the Atlantic.
Moderate air pollution levels are forecast for coastal northwest England, the north coast of Wales and some coastal areas of northeast England and southeast Scotland.
Find out more here.
People with hay-fever or respiratory conditions might find the next couple of days a bit difficult.
South easterly winds have brought some polluted air from Europe's cities to the UK.
This has the potential to cause high to very high air pollution.
The poor quality air will be flushed out as the wind changes direction on Thursday.
You can see more on the Air Quality Index here.