Export of atmospheric mercury from Asia

Emissions inventories indicate that Asian Hg sources are more than 50% of the global anthropogenic total. However, few measurements have been made to verify these large emissions. In this paper,we report on measurements of mercury from two sites during spring 2004 which received Asian outflow: Hedo Station,Okinawa (HSO),Japan and the Mt. Bachelor Observatory (MBO) in central Oregon,USA. At both sites,export of atmospheric mercury from China and East Asia was verified by the observations and meteorological data. The mean Hg 0 concentration we observed at HSO was 2.04 ng m � 3 ,which is significantly higher than the global background. Measurements of reactive gaseous mercury and particulate mercury at HSO found relatively little outflow of these compounds from Asia,generally less than 3% of the total mercury. By examining the correlation of Hg 0 to carbon monoxide during outflow events,we have derived an