Concentrations of Chemical Components, Including ²¹⁰Pb, Present in Aerosols Collected at Naha, Okinawa Prefecture, a Sub-tropical Region of Japan

Abstract

Aerosol samples were collected at Naha, Okinawa Prefecture, Japan during July 2001 to March 2005 to elucidate the concentrations of chemical components, including ²¹⁰Pb, present in air for a sub-tropical region of Japan. The NO₃^-, SO₄^2-, NH₄⁺ and Ca₂⁺ concentrations had clear seasonal variations and were high in winter to spring and low in summer. ²¹⁰Pb concentrations ranged from 0.10 to 1.52 mBq m^-3 and were low in summer and high in the other three seasons. The source of sulfur compounds in the aerosol samples was clarified by combining the sulfur isotope ratio δ³⁴S and ²¹⁰Pb concentrations. The multi-isotope method using δ³⁴S and ²¹⁰Pb concentrations was judged to be a good tool for understanding the transported sulfur source.