Abstract
Benzo (a) pyrene (Bap) in the atmosphere of northern industrial and commercial areas in Kyushu Island was periodically determined since 1959. The determination of Bap in the dust collected by deposit gauge and high volume air sampler was carried out by spectrophotometry after the purification of Bap with alumina column and acetylated paper. In Kita-Kyushu city, Bap contents in dustfall at 3 industrial districts were obviously different from those at 2 commercial districts. The annual mean values of Bap in dustfall from 1965 through 1970 were 67.9, 34 0, 51.3, 81. 7, 49.7 and 29.3 μg/m2 · month at the industrial districts, while 6.1, 6.7, 13.4, 28.3, 10.5 and 2.5 μg/m2 month at the commercial districts in Kita-Kyushu city. In Omuta city a chemical industrial city, Bap content in dustfall was not so high as observed at the industrial districts in Kita-Kyshu city, but gradual increase was observed from 1965 through 1970, that is, 9.6, 12.2, 11.6, 16.8, 27.6 and 23.6 μg/m2·month. The seasonal variation of Bap contents in suspended particulate matter in Kita-Kyushu city and in Fukuoka city was notable. However, this clear seasonal variation was lost after 1968 in proportion to the yearly decrease of Bap contents in suspended particulate matter. The highest amounts of Bap detected in suspended particulate matter was 121.3 μg/1000 m3 on November, 1967, in Kita- Kyushu city. The remarkable decrease of Bap in suspended particulate matter in the air of industrial and commercial area in northern districts of Kyushu Island, is considered to depend on strict legal regulation of air pollutants under the Air Pollution Control Law which was passed in 1967 in Japan.
