Department of Mechanical and Aerospace Engineering, University of California, Davis, One Shields Avenue, 2132 Bainer Hall, Davis, CA 95616, USA.
Department of Mechanical and Aerospace Engineering, University of California, Davis, One Shields Avenue, 2132 Bainer Hall, Davis, CA 95616, USA; Institute for Space Research, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
J Environ Sci (China). 2021 May;103:135-147. doi: 10.1016/j.jes.2020.10.003. Epub 2020 Nov 6.
Trace analysis of volatile organic compounds (VOCs) during wildfires is imperative for environmental and health risk assessment. The use of gas sampling devices mounted on unmanned aerial vehicles (UAVs) to chemically sample air during wildfires is of great interest because these devices move freely about their environment, allowing for more representative air samples and the ability to sample areas dangerous or unreachable by humans. This work presents chemical data from air samples obtained in Davis, CA during the most destructive wildfire in California's history - the 2018 Camp Fire - as well as the deployment of our sampling device during a controlled experimental fire while fixed to a UAV. The sampling mechanism was an in-house manufactured micro-gas preconcentrator (µPC) embedded onto a compact battery-operated sampler that was returned to the laboratory for chemical analysis. Compounds commonly observed in wildfires were detected during the Camp Fire using gas chromatography mass spectrometry (GC-MS), including BTEX (benzene, toluene, ethylbenzene, m+p-xylene, and o-xylene), benzaldehyde, 1,4-dichlorobenzene, naphthalene, 1,2,3-trimethylbenzene and 1-ethyl-3-methylbenzene. Concentrations of BTEX were calculated and we observed that benzene and toluene were highest with average concentrations of 4.7 and 15.1 µg/m, respectively. Numerous fire-related compounds including BTEX and aldehydes such as octanal and nonanal were detected upon experimental fire ignition, even at a much smaller sampling time compared to samples taken during the Camp Fire. Analysis of the air samples taken both stationary during the Camp Fire and mobile during an experimental fire show the successful operation of our sampler in a fire environment.
痕量分析火灾期间的挥发性有机化合物（VOCs）对于环境和健康风险评估至关重要。使用安装在无人机（UAV）上的气体采样装置在火灾期间进行化学采样空气非常有趣，因为这些设备可以在其环境中自由移动，从而可以获得更具代表性的空气样本，并能够对人类难以到达或危险的区域进行采样。本工作介绍了在加利福尼亚州戴维斯市采集的空气样本中的化学数据，这些空气样本是在加利福尼亚州历史上最具破坏性的野火——2018 年 Camp 火灾期间获得的，以及在受控实验火灾期间将采样装置部署在固定在无人机上时的情况。采样机制是一种内部制造的微气体预浓缩器（µPC），嵌入到一个紧凑的电池供电采样器中，然后将其送回实验室进行化学分析。使用气相色谱质谱法（GC-MS）在 Camp 火灾期间检测到了常见的野火化合物，包括 BTEX（苯、甲苯、乙苯、m + p-二甲苯和 o-二甲苯）、苯甲醛、1,4-二氯苯、萘、1,2,3-三甲苯和 1-乙基-3-甲基苯。计算了 BTEX 的浓度，我们观察到苯和甲苯的浓度最高，平均浓度分别为 4.7 和 15.1 µg/m。在实验火灾点火时，甚至在与 Camp 火灾期间采集的样本相比采样时间更短的情况下，都检测到了许多与火灾有关的化合物，包括 BTEX 和醛类化合物，如辛醛和壬醛。在 Camp 火灾期间固定采样和实验火灾期间移动采样的空气样本分析表明，我们的采样器在火灾环境中的运行是成功的。
