Abstract
Relationship between the areal distribution of SO2 pollutant and local wind flow pattern in South-Kanto district was analyzed in this paper.
The results of Factor-Analysis on interdiurnal variation of 20km2 mesh mean daily maximum concentrations show there are three distribution patterns regarding highly polluted area, that is, all over-high, south-high/north-low, and north-high/south-low.
Major local winds determining the highly polluted area are sea breeze from Tokyo Bay, southerly wind from Sagami Bay, easterly wind from Kashima Sea, and northerly wind from northern-western mountain area. When higher concentrations are observed all over area, sea breeze from Tokyo Bay prevails in the morning, and southerly wind from Sagami Bay penetrates to the north area in the afternoon. Under such a condition, higher concentrations are observed at southern area in the morning where pollutants discharged from the coast of Tokyo Bay transported with sea breeze from Tokyo Bay, and concentrations at northern area become higher in the afternoon where pollutants are transported with southerly wind from Sagami Bay. In the case of south-high/north-low, northerly wind from northern-western mountain area and easterly wind from Kashima Sea prevail throughout the day, and concentrations at southern area leeward of emission sources around Tokyo Bay become higher. In the case of north-high/south-low, southerly wind from Sagami Bay penetrates to the inland in the daytime, and higher concentrations are observed at northern area leeward of emission sources.
