The air quality in the Algarve, Alentejo, Lisbon, the Centre, the North Interior and Madeira has been badly affected by dust from the Sahara desert, reports the Portuguese Environment Agency (APA).
"During February 23rd, the influence of air containing particle concentrations will gradually decrease in intensity due to forecast changes in weather conditions," assures the APA website.
It is a natural phenomenon, most common in spring and summer, but does affect air quality and people should be warned.
Asthma sufferers and the elderly generally are advised to avoid strenuous exercise. For those who suffer from asthma or other respiratory distress, it is also a sign to restock the medicine cabinet with refills for antihistamines and inhalers.
The APA estimated that particles of between 40 and 80 mgm-3 have swept across the Algarve and Alentejo and between 10 and 40 mgm-3 in the Lisbon and Tagus Valley, Central and Northern Interior.
The analysis models shows the event should be over sometime on Wednesday .
The dust may settle on surfaces, visible on cars and outdoor furniture but is pretty harmless unless inhaled in quantity.
