Serial gas chromatographic/mass spectrometric measurements of some volatile organic compounds in the Arctic atmosphere during the 1992 Polar Sunrise Experiment

Variations of selected volatile organic compounds (11 halocarbons, 3 hydrocarbons, and acetone) in Arctic air were measured with an automated GC/MS at Alert, Canada, as a part of the 1992 Polar Sunrise Experiment. During the springtime ozone depletion, several volatile organic compounds (VOCs) correlated significantly with ozone. In particular, trichloroethylene had a strong positive correlation ( R = 0.90), while bromoform ( R = −0.87) and acetone ( R = −0.90) were negatively correlated. Isopentane ( R = 0.77), n ‐butane ( R = 0.77), and tetrachloroethylene ( R = 0.66) were also positively correlated with ozone. These findings suggest that the ozone depletion at Alert, including its small‐scale fluctuations, is caused by the advection of air masses in which reactions by Cl and Br atoms rapidly consumed chloroethylenes and alkanes concurrently and destroyed ozone while the air was over the ocean. In winter, however, slightly negative correlations of ozone with trichloroethylene ( R = −0.51) and tetrachloroethylene ( R = −0.40) were found, which may be caused by the vertical mixing of surface and free tropospheric air.