The increased pollution in Portugal began on October 6, with high levels of nitrogen dioxide and ozone. On the 15th, with the winds came the dust from North Africa, and with the fires, an excess of inhalable particles
The worst forest fires ever in Portugal, which on the 15th and 16th of this month burned at once an absolute record of more than 220 thousand hectares, causing 44 deaths, more than 70 injured, also led to a severe episode of air pollution.
Fumes and particles travelled to northern France and southern England, where they were enough to cloud the sun, and they also reached northern Germany and the Baltic states (see map below). In the country, the air measurement stations registered, on days 15 and 16, throughout the territory, levels of inhalable particles well above the legal limits.
The pollution, however, had already affected Portugal since 6th October because of the weather conditions, with intense heat and lack of wind, which caused high concentrations of pollutants (nitrogen dioxide and ozone) in the air. With the fires and atmospheric circulation, determined by Hurricane Ophelia, which brought a strong south wind, and together with it the dust of the desert from North Africa.
In those two days of fires, “there were air quality measurement stations that registered values four times the daily limit”, says Francisco Ferreira, professor and researcher at the New University of Lisbon in the area of air quality and president of environmental association Zero.
On 15th and 16th October stations throughout the territory reported inhalable particulate values above the limit of 50 micrograms per cubic meter (mg / m 3). “There were stations in the country that reached 300, and in Galicia, where there were also fires, reached 600 mg / m3, in Vigo and Santiago de Compostela, in these days,” Francisco Ferreira said.
In the Air Quality Index, the classification was in these days of “bad”, the worst of the scale, which remained on the morning of 17, but which later improved throughout the day with rain and the west wind that contributed to clean the atmosphere. On the 18th, the classification of air quality was already “very good” and “good” in all seasons of the country.