Simultaneous Monitoring of Outdoor PAHs and Particles in a French Peri-Urban Site during COVID Restrictions and the Winter Saharan Dust Event

International audience; The presence of polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM) in air is known to provoke deleterious effects on human health. This work focused on the monitoring of PM and PAHs in the air over four weeks in a peri-urban site in Strasbourg (France), using a three-stage cascade impactor and a particle analyser allowing PM1, PM2.5 and PM10 discrimination. Meteorological conditions were monitored to study their influence on the pollutant levels. The average PM10 concentration of the cascade impactor and particle analyser varied from 11.8 to 80.2 µg/m3 and 10.6 to 220.2 µg/m3, respectively. The PAH total concentration ranged in 1.1–7.6 ng/m3 and a predominance of 5- and 6-ring PAHs was observed. PAHs were also more abundant in finer particles (PM1). Specifically, identified PAHs are traffic tracers suggesting that vehicular emission was one of its main sources. Two pollution episodes, associated with either a Saharan dust wind episode or traffic pollution, were observed, and led to PM10 and PM2.5 surpassing the daily limit values established by the European Union despite the traffic limitations according to the COVID restrictions. The total PAH concentrations were the highest during these periods suggesting PAHs might be bound to and transported via dust particles.