Acid rain observations were done at 10 observation points from Katsuradai (660 m a. s. l.) to Murodo-daira (2450 m a. s. l.) in Mt. Tateyama and Toyama Science Museum in Toyama city. Some rain collectors set at Mt. Tateyama had been turned over by the strong wind of the typhoon during observation periods in 2018. Precipitations were increased with the rise in altitude (altitude effect). Concentrations of nitrate ions were decreased with the rise in altitude (altitude effect). However, it was observed during July to September that concentrations of non-sea salt sulfate ion increased with rise in altitude. Concentrations of ammonium ions at observation points of Mt. Tateyama were fluctuated in July and August though that concentrations showed altitude effect like as nitrate ion in September and October. These phenomena were similar to observations in 2017. Value of pH was the lowest at observation point of Murodou-daira in July and August. It was considered that the lowest pH at Murodou-daira was due to transported acidic constituent from the Asian Continent, because nitrate contribution ratio was the lowest. Number concentrations of suspended particles in precipitation collected at Oiwake (1800 m a. s. l.) from 18 to 29, August were the highest from other observation points, and sample water seemed pale yellow. These particles might be due to the Asian dust. The supplementary data is available from https://doi.org/10.6084/m9.figshare.7957145.
立山有料道路沿いの桂台(標高660 m)~室堂平(標高2450 m)までの10カ所と,科学博物館屋上の合計11カ所で酸性雨調査を継続している.2018年の観測結果では,降水量は観測点標高が高くなるにつれて増加した(高度効果).硝酸イオンでは観測点標高が高くなるにつれて濃度が低下する現象(高度効果)がどの月にも見られた.これらに対して,非海塩性硫酸イオンでは標高が高くなるにつて濃度が増加する現象(高度効果とは逆の現象)が7月~9月に観測された.また,アンモニウムイオンでは7月,8月は観測点によって濃度が大きく変動した.7月と8月の室堂での降水のpHの値は他の全ての観測点の中で最も低かった.室堂でのこれらの月の非海塩性硫酸イオン濃度は高く,硝酸寄与比の値は最も低かったことから,アジア大陸から酸性物質が輸送されてきたためと考えられた.また,8月18日~29日に追分で採取した降水は淡黄色を呈し,懸濁粒子数は他の観測点と比べて最も多かったことから黄砂を含んでいたものと推定された.