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 (RO3, the sum of ki[VOCi]) analyzer has been developed [1-5]. RO3 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) . To apply the analyzer to field observations, measurement tests of RO3 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 RO3 was corrected with observed NO concentration and correction factor considered . As a result of the test, RO3 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 (RO3) and the ambient temperature. It was found that observed RO3 increased with temperature increasing. It was suggested that observed RO3 could be explained by temperature dependence of BVOCs emission from plants.
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