Aerial Observations for 20 Years and Ground-Based Observations of Chemical Constituents of Aerosols Transported from East Asia

Abstract

Abstract Aerial observations over the seas between Asian continent and Japan were conducted for twenty years in order to analyze the transport and transformation of log-range transported atmospheric pollutants. Covered areas were the East China Sea, the Sea of Japan, and the Yellow Sea. Long term trend of atmospheric pollutants over the East China Sea was discussed on the basis of aerial observation data obtained since 1991. It was found clear upward trend of NO₃^-/SO₄^2- ratio which was caused by an increase of NO₃^- or a decrease of SO₄^2- or both. Ozone at a lower altitude showed a clear increase. Ground-based observations were done in April, October, December, 2012 and April, 2013 at Cape Hedo, Okinawa to analyze size-segregated chemical composition of aerosols. Eight kinds of ions (Cl^-, NO₃^-, SO₄^2-, Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺) were analyzed with ion chromatography. Species from anthropogenic sources such as NH₄⁺ and SO₄^2- were dominant in fine mode particles (0.5–1 μm, 0.1–0.5 μm). On the contrary, species from natural sources such as Cl^-, Na⁺, and Ca²⁺ were dominant in coarse mode particles (＞10 μm, 2.5–10 μm).