Presence and Source Attribution of Airborne Anthropogenic/Non-Sea-Salt Inorganic Chloride Determined by Filter-Pack Method at Eastern Edge in East Asia

摘要

The anthropogenic/non-sea-salt (nss) inorganic chloride in ambient air was evaluated from the viewpoint of its presence and source attribution by applying the four-stage filter-pack method. Observations were carried out for 1 year by sampling (both particulate matter and gaseous species) on a daily (24 h) basis. The anthropogenic/nss inorganic chloride was detected on 263 days (ca. 72% of the days in 1 year), and concentrations higher than 20 nmol∙m−3 were observed on 50 days (ca. 14% of the total sampling days). The source attribution was discussed, taking into account possible sources of in-country volcanic eruption, municipal waste incineration, domestic coal burning, and transboundary transportation. Concentrations of inorganic chloride higher than 20 nmol∙m−3 were predominantly observed with a northern wind direction, while high concentrations were infrequent when there was a southern wind direction, strongly suggesting that the in-country volcanic eruption had little influence on the high concentration of nss inorganic chloride. Wind speed had no relationship with concentrations higher than 20 nmol∙m−3, indicating that neither municipal waste incineration nor domestic coal burning had much impact on the high concentration. The statistical analyses of the backward trajectory indicated that the transboundary transportation from the area of the northeast and south of China, Mongolia, Russia, and the Sea of Japan contributed greatly to the high concentration of the anthropogenic/nss inorganic chloride along the eastern edge in East Asia.