Variations of airborne bacterial communities at high altitudes, over Asian-dust downwind area (Japan), in response to dust events. Helicopter Asian dust event

Asian dusts transport airborne microorganisms through free troposphere from the China desert areas to the downwind area in the East Asia, and can influence climate changes, ecosystem dynamics and human health. However, the variations of airborne bacterial communities in the free troposphere over the downwind area are poorly understood, and there are few studies reporting the effects of Asian dust event on the bacterial variations at high altitudes in depth. In this study, the vertical distributions of airborne bacterial communities at high altitudes were investigated, and the bacterial variations were compared between dust events and non-dust events.Aerosols were collected at the three altitudes from ground level to free troposphere (high level: 3,000m or 2,500 m, middle level: 1,200 m and low level: 10m) during the Asian dust events and non-dust events over the Noto Peninsula, Japan, where the westerly winds carry aerosols from the Chinese continental areas. During Asian dust events, air mass at high altitudes was transported from the Chinese desert region by westerly winds.