The loss of Cl as HCl from sea salt particles by air pollutants (NO3- and SO42-) in the marine atmosphere was discussed, based on both laboratory experiments and field measurements. In the laboratory experiments, the release of gaseous HCl from sea salt particles was simulated by passing NO2 or SO2 through a filter impregnated with sea water. The release of HCl from the filter occurred by the aeration with NO2 or SO2, and the concentration of HCl released depended on both the concentration of NO2 or SO2 and relative humidity. The generation rates of HCl calcurated from the added amounts of NO2 and SO2 were 9% for NO2 and 18% for SO2 (Table 1 and 2). The marine aerosol was collected by Andersen samplers during January 13~20 and December 14~20, 1981 in the two remote islands, Hachijo-jima and Chichi-jima in order to investigate the CI loss from sea salt in the marine atmosphere. The calcurated Cl losses from sea salt particles (<2/μm) based on the Cl/Na ratio in sea water (1.8) were 0.21 to 0. 36μg/m3, and 2 to 7% of total particulate marine Cl at the two islands. The Cl loss from sea salt particles smaller than lμm was more than 20%, while that from particles larger than 2μm was negligible (Fig. 4). A linear correlation was observed between measured SO42- concentrations (<2μm) and Cl losses, indicating a 1.1 μmol/m3 Cl loss per 1 μmol/m3 SO42- (Fig. 5). The HCl concentrations estimated from the Cl losses (5. 9×l0−3 to 10×l0−3μmol/m3) agreed with the measured HCl concentrations in the marine atomosphere (4. 8×l0−3 to 15×l0-7#x03BC;mol/m3) (Table 5), suggesting that the release salt particles is the main source of gaseous HCl in the marine atomosphere.
ASJC Scopus subject areas
- Chemical Engineering(all)