FOG CHEMISTRY AT THE NEW-ENGLAND COAST - INFLUENCE OF AIR-MASS HISTORY

During the spring, summer and fall seasons of 1990, we sampled fog at a coastal location in New England for chemical analysis. For the 6 sampled events, 72 h back trajectories were calculated for the associated air masses. We found that air masses leading to the sampled fog events reached our site from south/southwesterly to southeasterly directions. The chemical composition of the fog was temporally variable within a single event and even more so for event-to-event comparisons. The less polluted air masses originated over the Atlantic Ocean, but also showed influence of pollution which they may have picked up during their short travel time along the New England coast. The more polluted air masses traveled a significant amount of time over New England, some of them along the coast, and they probably became contaminated with regional pollution. This pattern explains the high concentrations of fog water compared to other sites in the U.S.A. as,well as the high heterogeneity in our data set.