ATMOSPHERIC OBSERVATIONS OF AEROSOL BLACK CARBON, CARBON-DIOXIDE, AND METHANE IN THE HIGH ARCTIC

Hourly aerosol black carbon concentrations from Alert, Canada (82.5 degrees N, 62.3 degrees W) for 1989-1990 are summarized. Maximum concentrations recorded during the winter months were in the order of 300 ng m(-3), bet summer concentrations were frequently below detection limits. Monthly median values of black carbon and sulphate showed a similar annual variation characteristic of the cycle of Arctic Haze. In addition, the hourly black carbon data exhibited considerable episodic behaviour over periods of a few days to a week. These elevated concentrations of black carbon were most often correlated with increases in carbon dioxide and methane concentrations. Such correlations can arise from several causes, but transport of a polluted air mass from industrialized regions to the high Arctic would account for the simultaneous increases in numerous monitored constituents, and is consistent with previous studies of Arctic Haze. On longer time scales, the significance of the different sinks for black carbon, carbon dioxide, and methane becomes apparent especially during the summer months.