According to the Directorate-General for Health (DGS), this North African air mass which carries suspended dust, is expected to cross mainland Portugal throughout the day today and Tuesday.

"There is a situation of poor air quality in the continent, with an increase in the concentrations of inhalable particles of natural origin in the air affecting the regions of the Alentejo, Algarve and the interior of the Central region", says the DGS in a statement published on its website.

According to the DGS, this pollutant (inhalable particles - PM10) has effects on human health, especially in the most sensitive of the population which includes children and the elderly, whose health care should be kept an eye on during the occurrence of these situations.

As long as this phenomenon is maintained, the Directorate-General for Health issues a set of recommendations for the general population and those most vulnerable.

The general population should avoid prolonged efforts, limit outdoor physical activity and exposure to risk factors such as tobacco smoke and contact with irritating products.

On the other hand, children, the elderly, patients with chronic respiratory problems, such as asthma, and patients in the cardiovascular forum, in addition to complying with the recommendations for the general population should, whenever feasible, remain inside buildings and, preferably, with windows closed, due to "their greater vulnerability to the effects of this phenomenon".

The health authority advises chronic patients to keep medical treatment in progress and, in case of worsening symptoms, contact Health Line 24 (808 24 24 24) or use a health service.