Determination of rate constants of gas-phase reactions of α-pinene and β-pinene with ozone

alpha -pinene and beta -pinene are the most dominating species among natural terpenes. Terpenes are mainly emitted from forest trees, flowers and grass. In the lower troposphere terpenes can react fast with OH radical, ozone, NO3 radical and ground state oxygen atom. These reactions may contribute to the occurring of aerosols, peroxides (hydrogen peroxide and organic peroxide), carbon cycle (mainly OO),acid rain (organic acids,NO3- and SO42-) ozone and active radicals such as OH radical. Reactions with ozone occur both in the daytime and in the night. The study in this field in China began in the late 1980. The main work focus on the source emission and the experimental simulation has just started. It is most of our group's work. In this paper preliminary experimental simulation of the gasphase reactions of alpha -pinene and beta -pinene with ozone were carried out in the quartz chamber. The rate constants of these reactions were measured using long-path Fourier transform infra-red combined with relative rate constant method. And the rate constants for the gasphase reactions of alpha -pinene, beta pinene with ozone were determined as 2.83 X 10(17) cm(3 .)molecule-(1.)s(-1) and 1.48 X 10(17) cm(3 .)Molecule(-1 .)s(-1) at 1.0 X 10(5) Pa and 296 +/- 3 K. The results are quite similar to the data from Atkinson group. No cyclohexane was added to the reaction system during the measurement to restrain the formation of OH radical. The formation of OH radical could not be quantified, so that the effect of subsidiary reactions induced by OH radical has not been calculated. In the later simulation study and model this effect should be considered.