Saharan Dust over Europe and the Atlantic

Last updated May 29, 2026 · 6 min read

The Sahara is the planet's largest source of mineral dust, and its plumes routinely travel thousands of kilometres — north over Europe and west across the Atlantic. When they arrive, skies turn milky orange, cars are filmed in beige grit, and particulate readings spike. This guide explains how the dust travels, when, and what it means for the air you breathe.

Two main pathways

Saharan dust leaves the desert in two broad directions:

• North, over Europe. Southerly winds carry dust over Spain, Portugal, France, Italy, and sometimes as far as the UK and Scandinavia. In Spain and the Canary Islands this is known as calima; elsewhere the dust often washes out in rain as "blood rain," leaving a reddish film. It can dust the Alps orange.
• West, across the Atlantic. A vast, dry, dusty mass called the Saharan Air Layer (SAL) rides the trade winds across the ocean to the Caribbean and the south-eastern United States, mainly from June to August. The same dust that hazes Miami's sky also fertilises the Amazon with mineral nutrients and tends to suppress Atlantic hurricane formation.

The season

European episodes are most common in spring and summer but can occur in any month given the right winds. The trans-Atlantic SAL transport peaks in the early-to-mid Atlantic hurricane season, June through August.

The record 2022 episode

In February and March 2022, an exceptionally intense plume swept over Spain and France. Parts of Spain recorded some of their highest PM10 readings on record, snow in the Pyrenees and Alps turned orange, and the dust reached far into northern Europe — one of the most dramatic Saharan-dust events in recent memory.

The health angle

Saharan dust raises PM10 sharply and can lift PM2.5 too. Coarse dust irritates the eyes, nose, and throat and can aggravate asthma and other respiratory conditions; the finer fraction penetrates deeper into the lungs. Because the dust is natural, regulatory agencies sometimes flag dust-affected days separately when assessing whether legal limits were exceeded — but the health exposure is real regardless of the source.

How it shows up in the index

In Europe, a dust episode pushes the European Air Quality Index up via its PM10 (and sometimes PM2.5) sub-index. CAMS forecasts dust transport days in advance, so national services can warn ahead of a plume's arrival. On the US side of the Atlantic, the same dust elevates PM2.5 in Florida and the Gulf Coast in summer.

What to do during a dust episode

• Check your local index and the CAMS dust forecast when a plume is expected.
• Limit prolonged outdoor exertion if you have asthma or another respiratory condition.
• Keep windows closed at the peak and rinse dust off rather than letting it linger.

Primary sources: Copernicus Atmosphere Monitoring Service (CAMS) · European Environment Agency — European AQI