Airborne particulate pollution in the greater Thessaloniki briefly surged to nearly twice its normal levels after a major wildfire broke out late Saturday in the Oreokastro area, northwest of Greece’s second-largest city, with smoke blanketing parts of the metropolitan area until shifting winds dispersed the plume on Sunday morning.
Municipal air quality monitoring stations recorded the highest concentrations between midnight and 10 a.m. Sunday, when smoke from the wildfire drifted over the city. Environmental officials said conditions improved rapidly after a strong northwesterly wind that frequently clears Thessaloniki’s atmosphere, pushed the smoke southward.
The sharpest increase was observed in PM10 particulate matter, microscopic particles produced largely by combustion that can penetrate the respiratory system. Readings at the Egnatia monitoring station in the city center reached between 60 and 85 micrograms per cubic meter, compared with typical levels of 25 to 50. At the city hall station, PM10 concentrations measured between 40 and 50 micrograms per cubic meter, above the normal range of 15 to 30.
Levels of finer PM2.5 particles, which pose greater health risks because they can reach deep into the lungs and enter the bloodstream, also rose significantly. Officials said pollution levels in central Thessaloniki were approximately double their usual values during the peak of the smoke episode but emphasized that the deterioration was temporary and did not require emergency public health measures. Regulatory restrictions are imposed only after repeated exceedances of daily air quality limits over the course of a year.
The latest measurements came as Greece remained on high wildfire alert following several major blazes over the past 48 hours. Large fires around Thessaloniki, west of Athens and in the eastern Peloponnese forced precautionary evacuations, damaged homes and businesses and mobilized hundreds of firefighters backed by aircraft and helicopters.
Strong winds and prolonged dry conditions have continued to fuel an elevated wildfire risk across much of the country, prompting authorities to urge residents to remain vigilant and avoid activities that could spark new fires.
