Meteolux have issued an orange air quality alert for Friday and all of Saturday, covering the entirety of the country.
This is based on data from the ministry for the environment, climate and sustainable development, who release regular reports on the air quality in the country.
In their most recent report, they note that the change in temperature and air pressure "significantly limits the dispersion of air pollutants" which means that the concentration of fine particles (PM10) increases. The levels are expected to exceed the daily threshold of 50 µg/m3.
The risk is particularly high in southern parts of the country, and the accumulation of pollutants on Friday combined with relatively still air means that the risk is maintained going into Saturday.