Evolution of the chemical composition of fogwater collected at four sites in the Alsace region between 2015 and 2021

Abstract Four sites representing urban (Strasbourg), suburban (Geispolsheim and Cronenbourg), and rural (Erstein) in the Alsace region, north east of France are sampled to investigate the evolution of the chemical composition of fog water between 2015 and 2021. For this aim, forty-two fog samples are collected using a Caltech Active Strand Cloud Collector (CASCC). The samples are analyzed for their inorganic species (metals and ions) and their physico-chemical properties (pH, dissolved organic carbon (DOC), liquid water content (LWC), and conductivity (K)). Temporal and spatial evolutions have been also investigated between the four sampling sites. Our results are then compared to previous studies performed in 1990’s at Strasbourg. Since 1999, there is a lack of fog knowledge in Strasbourg metropolitan and complete absence of fog studies. That’s why it is interesting to resume fogwater collection in order to re-build a solid background regarding air quality in France, particularly in Alsace, and assess the effectiveness of the rules and regulations that have been implemented over time.