A smog chamber for studies of the reactions of terpenes and alkanes with ozone and OH.

The design and performance of a smog chamber for the study of photochemical reactions under simulated environmental conditions is described. The chamber is thermostated for aerosol experiments, and it comprises a gas chromatographic sample enrichment system suitable for monitoring hydrocarbons at the ppbv level. By irradiating NOx/alkane-mixtures rate constants for the reaction of OH radicals with n-alkanes are determined from n-pentane to n-hexadecane to be (k+-2sigma)/10E12 cubicmeters s-1 = 4.29+-0.16, 6.2+-0.6, 7.52 (reference value),8.8+-0.3, 10.2+-0.3, 11.7+-0.4, 13.7+-0.3, 15.1+-0.5, 17.5+-0.6, 19.3+-0.7, 22.3+-1.0, and 25.0+-1.3, respectively at 312 K. Rate constants, (k+-2sigma)/10E17 cubicmeters s-1, for the reaction of ozone with trans-2-butene (21.2+-1.0), cis-3-methylpentene-(2) (47.2+-1.7), cyclopentene (62.4+-0.2), cycloheptene (28.3+-1.5), alpha-pinene (8.6+-1.3, and beta-pinene (1.4+-3.5) are determined in the dark at 297 K using cis-2-butene(13.0) as reference standar d. (ITA