SPRING 1989 OBSERVATIONS OF LOWER TROPOSPHERIC CHEMISTRY IN THE CANADIAN HIGH ARCTIC

In the spring of 1989, airborne observations were made of C-2-C-4 hydr ocarbons, ozone, and aerosols in the tropospheric boundary layer over a 96,000 km(2) area in the vicinity of Alert, NWT, Canada (82.5 degree s N, 61.5 degrees W). Samples were collected in stainless steel canist ers and on filters. Aerial ozone measurements, particle counting measu rements, and meteorological observations were also made. Analysis of t he canister and filter samples has provided data on C-2-C-4 hydrocarbo ns and ionic species (Cl-, Br-, NO3-, SO42-, Na+, K+, and NH4+). These data, together with observations of ozone, have provided further insi ght into the near-ground level ozone depletion during the Arctic sprin g. A positive correlation between the concentrations of ozone, ethane, propane, i-butane, n-butane, and acetylene was observed. In addition, there is an indication of a negative correlation between ozone concen trations and filterable bromine. An analysis of the relationship betwe en the concentrations of ozone and hydrocarbons has provided evidence that chlorine atoms may be responsible for the observed depletion of h ydrocarbons, but not ozone. The latter is more readily explained by re action with bromine atoms.