Mitsuhiro Matsumoto

Long term measurements of atmospheric gaseous and aerosol species using an annular denuder system in Nara, Japan

During the period from June 1994 to May 1995 a three-line annular denuder filter system was used to sample atmospheric gas phase SO2, HNO3, HNO2, HCl, and NH3 and aerosol phase SO2-4, NO-3, Cl-, NH+4, Na+, K+, Ca2+, and Mg2+ in Nara, Japan. The average annual concentrations of these species were determined together with their seasonal variations. It was found that even in a medium-sized city such as Nara HNO3 and HNO2 concentrations were fairly high. The present system also enabled the determination of the percent loss of aerosol components NO-3, Cl- and NH+4 collected on filters.

Spatial differences of chemical features of atmospheric deposition between rainy season and winter in the areas facing to the Japan sea, Japan

Atmospheric deposition was collected using filtrating bulk samplers at 32 sites in the areas facing to the Japan Sea (AFJS) from April 1991 to March 1994. The data were analyzed for winter (January and February) and the rainy season (June and July) when the climate is just the opposite. The AFJS was geographically divided into five areas, that is western Tohoku (WT), Hokuriku (HR), eastern San-in (ES), western San-in (WS) and northern Kyushu (NK). WT, HR and ES receive more precipitation than other regions in winter. H+ depositions increase in winter except NK. This is mainly due to high winter H+ concentrations. In spite of large amounts of precipitation in WT, HR and ES in winter, nss-SO4(2-) concentration was nearly equal to the average throughout Japan. Namely, nss-SO4(2-) depositions in these areas were nearly twice the national mean. In WT, HR and ES, nss-Ca2+ concentrations in winter are lower than the average of the whole country (less than the half). This may be the cause of the lower potentials of neutralization and the higher remaining acid concentrations in WT, HR and ES than NK and WS.

Automated Sampling and Analysis of Precipitation

取す るという画期的な装置であ った.こ の装置 は最 初 口径が200mmφ と小 さか ったため ,後 に355mmφ と改 良 され,全 国に普及 していった(図-5) . 続 いて,1970年 代前 半 の被害 発生 によ り,pHな ど の 自動測定機 の開発が望 まれ るようにな り19) ,感 雨器 を用 いたR-1500型 が製作 された(図 一6).し か し, この当時 と して はかな り高価な装 置であ った ことと , 他 の地域 で はまだ酸性雨問題 が本格化 していなか った ことによ り,関 東周辺以外 にはほとん ど普及 しなか っ た.こ れとと もに,湿 性降下物を簡便 に採取 す る装 置 の出現が多方 面 か ら望 まれ,自 動開 閉蓋 付 きのR200型 自動雨水採取装置が作成 され た.こ の装 置 は価 格 が手 頃で使 いやす いこともあ り,全 国 に普及 して い る(図 一7). これ らは,降 水 のみの採取 を目的 と した もので あ っ たが,降 下量 などの把握 の必要性か ら,湿 性/乾 性降 下物 ・分別採取装 置が望 まれ るようにな った.そ して , 1983年 か ら5か 年間 の7都 道府県によ る環境庁 委託の