Abstract To investigate tropospheric ozone, O3, and secondary organic aerosols, SOAs, reactivities of biogenic volatile organic compounds, BVOCs, with atmospheric oxidants have been focused on. In this study, as an ensemble monitor covering all ozone-reactive BVOCs, the analyzer of total ozone reactivity, RO3, was modified and applied to the ambient observation of RO3 in a forest. The analyzer was improved to realize the RO3 measurements of ambient BVOCs in low concentration. After improvement, the typical limit of detection of present RO3 analyzer was determined as 1.5 × 10−5 s−1 (S/N = 3, 600-s average) under laboratory conditions. For the atmospheric observation, it is important to consider coexisting compounds in the ambient air. It was confirmed that the configurations of dual chemiluminescence detectors (CLDs) could reasonably cancel out the contributions of ambient ozone. It is also necessary to distinguish the contributions of NO (RNO) from total ozone reactivity (RALL). The method for quantifying RNO was also established. Contributions of VOCs, RO3, to RALL were acquired by subtracting those of NO and NO2 from measured RO3. It was confirmed that the present analyzer had capability to quantify RO3 down to 4 × 10−5 s−1 as the overall limit of detection under ambient conditions. Then, trial observations of RO3 were conducted in a suburban forest in Japan. RO3 data were acquired successfully for a total of 8 days, including high temperature days over 35 °C. It was confirmed that RO3 could be significantly quantified utilizing the present analyzer when temperature was high enough and NO level was insignificantly low. Fractional contributions of VOC, NO, and NO2 to O3 loss reactions were also investigated. As a result of regression analysis between RO3 and temperature, a clear dependence of RO3 on temperature was observed in the afternoon. When the temperature dependent algorithm was considered, the temperature sensitivity was acquired as 0.23 ± 0.03 K-1 (26% K−1), which was comparable to those in previous studies on monoterpene emission from vegetation. The RO3 analyzer might also capture the early morning peak of monoterpene emission in a forest though the uncertainties were large due to fluctuations of NO. Consequently, it was confirmed that the present RO3 analyzer be useful for investigating BVOCs in a forest. Especially, monoterpene emission under elevated temperature conditions up to 36.2 °C was significantly captured during the RO3 observation in the forestal atmosphere.

中文翻译：

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日本郊区森林中总臭氧反应性的测量

摘要 为了研究对流层臭氧、O3 和二次有机气溶胶 SOA、生物挥发性有机化合物 BVOCs 与大气氧化剂的反应性。在这项研究中，作为覆盖所有臭氧反应性 BVOCs 的集合监测器，总臭氧反应性分析仪 RO3 被修改并应用于森林中 RO3 的环境观察。对分析仪进行了改进，实现了低浓度环境BVOCs的RO3测量。改进后，现有 RO3 分析仪在实验室条件下的典型检测限为 1.5 × 10-5 s-1（S/N = 3，平均 600-s）。对于大气观测，重要的是要考虑环境空气中的共存化合物。经证实，双化学发光检测器 (CLD) 的配置可以合理地抵消环境臭氧的影响。还必须区分 NO (RNO) 和总臭氧反应性 (RALL) 的贡献。还建立了定量RNO的方法。通过从测量的 RO3 中减去 NO 和 NO2，获得 VOC RO3 对 RALL 的贡献。经证实，本分析仪有能力将 RO3 量化至 4 × 10-5 s-1，作为环境条件下的总体检测限。然后，在日本郊区的森林中对 RO3 进行了试验观察。共 8 天成功获取 RO3 数据，包括超过 35°C 的高温天数。证实当温度足够高且 NO 水平微不足道时，使用本分析仪可以显着量化 RO3。还研究了 VOC、NO 和 NO2 对 O3 损失反应的部分贡献。作为 RO3 与温度之间回归分析的结果，在下午观察到 RO3 对温度的明显依赖性。当考虑温度相关算法时，获得的温度灵敏度为 0.23 ± 0.03 K-1 (26% K-1)，这与先前关于植物单萜排放的研究相当。RO3 分析仪也可能捕获森林中单萜排放的清晨峰值，尽管由于 NO 的波动而不确定性很大。最后，已证实本 RO3 分析仪可用于调查森林中的 BVOC。特别是，在森林大气中的 RO3 观测期间，显着捕获了在高达 36.2 °C 的高温条件下的单萜排放。