MADRID (AP) — Spain issued extremely poor air quality ratings for Madrid and a large swath of the country Tuesday after a mass of hot air from the Sahara dumped dust after crossing the Mediterranean.

Spain’s national air quality index qualified as “extremely unfavorable” — its worst rating — the capital and large parts of the southeast coast.

Many Spaniards awoke to find a layer of red dust covering terraces, streets and cars. The sky in the capital and other cities was tinged orange.

Emergency authorities have recommended citizens use face masks if they go outside, and avoid outdoor exercise.

The wave of hot air has also affected the air quality in areas north of Madrid, as far west as in the Canary Islands in the Atlantic Ocean and in the Balearic Islands in the Mediterranean.