Natural versus anthropogenic inhalable aerosol chemistry of transboundary East Asian atmospheric outflows into western Japan

► Transboundary transport of aerosols from mainland Asia damages air quality in Japan. ► Desert-derived supermicron dusts mix with traffic and industry-derived submicron pollutants. ► Anthropogenic outflows create atmospherically persistent metalliferous sulphate hazes. ► Low V/Rb and NO3−/SO42−, high As, and unfractionated La/Ce implicate coal emissions.