Pollutionwatch: how much Sahara desert dust do we breathe?

Dust that swept Europe in February affects weather systems but also contains many allergens

Saharan dust high in the skies over Europe caused some spectacular sunsets in February. Many of us found dust on our cars, and Alpine snow has been stained orange, but finding out how much Saharan dust we are breathing has always been difficult. For decades we have been measuring the amount of particle pollution in the air, but not what it is made of. However, university-run air observatories in London, Birmingham and Manchester are now making real-time chemical analysis. They showed that silicon, aluminium, calcium and iron particles from Saharan dust were the main particle pollutants in all three cities on Saturday 20 February and that the dust was breathed by Londoners for the next two days.

Saharan dust events are common in Mediterranean countries. It is also carried west on Atlantic trade winds. Dust from north Africa fertilises the Amazon, but it also causes air pollution problems in Caribbean islands and the southern US.