CASE-STUDIES ON THE CHEMICAL-COMPOSITION OF FOGWATER - THE INFLUENCE OF LOCAL GASEOUS EMISSIONS

In order to study the mechanisms governing the composition of fogwater, sequential samples were taken during two fog events over several hours and analyzed chemically. In addition, preliminary measurements of gases (HC1, HNO//3, NH//3) and aerosols (H//2SO//4, NH//4NO//3, NH//4Cl and ammonium sulfates) were made. The uptake of gaseous HCl in the fog droplets was a major source of acidity. The NH** plus //4,NO** minus //3 and SO//4**2 minus concentrations (in the range of 0. 1-2 mmol L-SCRIPT ** minus **1) were regulated by the inputs of aerosols and the liquid water content of the fog. The contribution of dissolved S(IV) (0. 06-0. 27 mmol L-SCRIPT ** minus **1) to the total aqueous sulfur varied with time, according to the pH-dependent solubility of SO//2 and to oxidation reactions.