All over the papers and for that matter all over our cars in Britain for the last couple of days, has been a type of Sahara sand dust.
According to the BBC News '
People with health problems are being warned to avoid strenuous activity after forecasts that air pollution will reach high levels in parts of England'.
Defra issued warnings as high pollution levels were recorded on Tuesday.
The pollution - a mix of local and European emissions and dust from the Sahara - is forecast in parts of south England, the Midlands and East Anglia.
The elderly and those with lung or heart disease are among those warned against exercising outside.
In February, the European Commission launched legal proceedings against the UK for failing to reduce levels of nitrogen dioxide (NO2) air pollution.
On Wednesday, Defra (the Department for Food, Agriculture & Rural Affairs) admitted it was a "challenge" to meet air pollution targets near busy roads but said air quality had "improved significantly" in recent decades.
Even the Prime Minister, David Cameron's car was covered in the Sahara dust.
Defra has a 10-point scale for measuring air quality - with level one implying a "low" risk of air pollution and 10 warning of "very high" levels.
Levels are determined by the concentration of five pollutants in the air, including NO2, sulphur dioxide (SO2) and ozone.
High levels of air pollution are usually reached about five times a year, Defra said.
On Wednesday, levels were recorded at six - meaning moderate - in East Anglia and south-east England, with pollution readings reaching level five in London and areas of north-east England.
However, forecasters say pollution levels could reach high levels later in the day and on Thursday, before clearing on Friday.
The BBC weather centre said the highest recordings were likely to be in East Anglia and the East Midlands, while moderate to high air pollution levels were also forecast for large parts of southern and central England.
