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Absolute rate constants and their temperature dependencies for the deactivation of O(1D) by five important atmospheric gases are reported. O(1D) atoms are produced by photolysis of ozone at 266 nm and the atoms are directly observed in time resolved decay of the O(1D) →O(3P) radiation at 630 nm. Gases which only quench O(1D) (O2, N2, and CO2) are observed to have a small negative temperature dependence while O3 and H2O, which also have a reactive channel, display no temperature dependence. Arrhenius expressions for the reactions measured are (A in units of 10−10 cm3/molecule⋅ s, E in cal/mole) O2(T=104–354 K) 0.29 exp(134/RT), N2(T=104–354 K) 0.20 exp(214/RT), CO2(T=139–200 K) 1.2 and (T=200–354 K) 0.68 exp(233/RT). The rate constants for O3 and H2O are 2.4×10−10 and 2.3×10−10 cm3/molecule⋅ s over ranges of 103–393 K and 253–353 K, respectively. The results are compared with other energy dependent measurements and with the theories reported in the literature.

AIIIttact-Measurements of formaldehyde, acetaldehyde, acetone and propionaldehyde concentrations were made at two rural sites in central Ontario. One site (at Egbert, Ont.) is located~60 km northwest of Toronto, while the other site

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