[A-AS06] Atmospheric Chemistry

[AAS06-P31] Temperature dependence of ozone reactivity observed at a suburban site in Japan

*Jun Matsumoto¹ (1.Faculty of Human Sciences, Waseda University)

Keywords:biogenic VOCs, field observation, emission

Biogenic volatile organic compounds (BVOCs) have been focused on as precursors of tropospheric ozone (O₃) and secondary organic aerosols. Various species of BVOCs have C=C double bonds and can react with O₃. To capture BVOCs comprehensively, a total ozone reactivity (R_O3, the sum of k_i[VOC_i]) analyzer has been developed [1-5]. R_O3 of sample BVOCs can be determined when decrease of O₃ due to BVOCs+O₃ is precisely monitored. In our previous studies, the detection limit of the analyzer reached 2 x10^-5 s^-1 (S/N=3, 60-s average, 50-s reaction) [5]. To apply the analyzer to field observations, measurement tests of R_O3 in the ambient air were conducted in this study. The observation was conducted at a suburban site, Tokorozawa campus, Waseda University, Tokorozawa, Saitama, Japan, on July 6 and 7, 2016, and April 30, May 3, July 19, 20 and 21, 2017. Contribution of ambient NO on R_O3 was corrected with observed NO concentration and correction factor considered [6]. As a result of the test, R_O3 was significantly captured when the temperature was high during daytime in summer. Fig. 1 shows an example of correlation plot between the observed ozone reactivity (R_O3) and the ambient temperature. It was found that observed R_O3 increased with temperature increasing. It was suggested that observed R_O3 could be explained by temperature dependence of BVOCs emission from plants.
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[5] Matsumoto, J., IGAC2016 Science Conference, 4.05 (2016).
[6] Matsumoto, J., and Sommariva, R., JpGU-AGU Joint Meeting 2017, AAS11-P01 (2017).