C. Deserves, GAS-PHASE FORMALDEHYDE AND PEROXIDE MEASUREMENTS IN THE ARCTIC ATMOSPHERE, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 99(D12), 1994, pp. 25391-25398
Atmospheric peroxides and formaldehyde were measured during the Polar
Sunrise Experiment 1992 in Alert, Canada (82.5 degrees N, 62.3 degrees
W). Two measurement periods, in the dark winter and in the sunlit spr
ing, were chosen to investigate the effects of photochemistry. Continu
ous measurements were performed using diffusion scrubbers coupled to a
queous phase fluorometry. The concentration of total peroxides varied
from below the detection limit (similar to 10 parts per trillion by vo
lume (pptv)) to 40 pptv in the dark and 100 to 400 pptv in the sunlit
period with large variations in the ratio between H2O2 and organic per
oxides. The CH2O concentrations measured in the dark were between 100
and 700 pptv and showed good correlation with a number of atmospheric
constituents such as CH4, CO2, and Rn but anticorrelation to O-3. A fr
action of the observed CH2O concentrations is believed to be formed by
nonphotochemical O-3-alkene chemistry. In the presence of sunlight th
e CH2O concentrations ranged between 30 to 600 pptv without correlatio
n to CH4, CO2, or Rn. The maximum CH2O concentrations were associated
with air, depleted in O-3 coming from the Arctic Ocean. During the O-3
depletions, decreased peroxide concentrations were observed. The orig
in of the air mass was a very important factor during both periods in
explaining the observed variabilities in CH2O and peroxide concentrati
ons.