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 hydrocarbons, ozone, and aerosols in the tropospheric boundary layer over a 96,000 km(2) area in the vicinity of Alert, NWT, Canada (82.5 degrees N, 61.5 degrees W). Samples were collected in stainless steel canisters and on filters. Aerial ozone measurements, particle counting measurements, and meteorological observations were also made. Analysis of the canister and filter samples has provided data on C-2-C-4 hydrocarbons and ionic species (Cl-, Br-, NO3-, SO42-, Na+, K+, and NH4+). These data, together with observations of ozone, have provided further insight into the near-ground level ozone depletion during the Arctic spring. 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 concentrations and filterable bromine. An analysis of the relationship between the concentrations of ozone and hydrocarbons has provided evidence that chlorine atoms may be responsible for the observed depletion of hydrocarbons, but not ozone. The latter is more readily explained by reaction with bromine atoms.