Impact of a Saharan dust outbreak on PM

Southeastern France is often subject to thermal breezes and inversions that are partly responsible for the dispersion behavior of air pollutants in this region. Generally, the coastal urban zone is the main contributor to PM10 emissions. However, a southerly wind, commonly known as Sirocco, occasionally generates dust advections from the Sahara desert, resulting in poor air quality in the study area. This work demonstrates the quick rise of PM10 levels on the French coastline under the influence of such a weather outbreak. Measurements were performed during a Saharan dust episode which occurred end of April 2013 and caused the tripling of PM10 daily averages at the regional scale in about 24 hours. In Vence, located in the Alpes-Maritimes department, the highest daily average was 7 times greater during the peak than before the dust outbreak. In Venaco (Corsica) off-line chemical characterizations for filter samples show that about 50% of the PM10 mass was composed of terrigenous dust, which confirms that they played a central role in the degradation of air quality and in the exceeding of the EU daily limit value of 50 μg/m3 at a regional scale