Low molecular weight organic acids in fogwater in an urban area: Strasbourg (France)

This work presents the chemical analysis of low weight carboxylic acids: formate and acetate in two droplet-size categories (2–6 and 5–8 μm) of fogwater collected in Strasbourg (eastern France) between 1991 and 1994. For each sample, the ratio between acetate and formate was calculated, in many cases, this ratio was typically higher than one. This calculation indicates that the origin of acetate and formate can be attributed to automobile exhaust. Maximum contribution of these acids to the total free acidity of fogwater was also checked and the results show that the contribution is very low in regard to the strong mineral acids from anthropogenic origin.