Monitoring and Laboratory Division, California Air Resources Board, Sacramento, CA, USA.
Desert Research Institute, Nevada System of Higher Education, Reno, NV, USA.
J Air Waste Manag Assoc. 2020 Feb;70(2):158-179. doi: 10.1080/10962247.2019.1654036. Epub 2020 Jan 6.
Increases in large wildfire frequency and intensity and a longer fire season in the western United States are resulting in a significant increase in air pollution, including concentrations of PM (particulate matter <2.5 µm in aerodynamic diameter) that pose significant health risks to nearby communities. During wildfires, government agencies monitor PM mass concentrations providing information and actions needed to protect affected communities; this requires continuously measuring instruments. This study assessed the performance of seven candidate instruments: (1) Met One Environmental beta attenuation monitor (EBAM), (2) Met One ES model 642 (ES642), (3) Grimm Environmental Dust Monitor 164 (EDM), (4) Thermo ADR 1500 (ADR), (5) TSI DRX model 8543 (DRX), (6) Dylos 1700 (Dylos), and (7) Purple Air II (PA-II) in comparison with a BAM 1020 (BAM) reference instrument. With the exception of the EBAM, all candidates use light scattering to determine PM mass concentrations. Our comparison study included environmental chamber and field components, with two of each candidate instrument operating next to the reference instrument. The chamber component involved 6 days of comparisons for biomass combustion emissions. The field component involved operating all instruments in an air monitoring station for 39.5 days with hourly average relative humidity (RH) ranging from 19% to 98%. Goals were to assess instrument precision and accuracy and effects of RH, elemental carbon (EC), and organic carbon (OC) concentrations. All replicate candidate instruments showed high hourly correlations (R ≥ 0.80) and higher daily average correlations (R ≥ 0.90), where all instruments correlated well (R ≥ 0.80) with the reference. The DRX and Purple Air overestimated PM mass concentrations by a factor of ~two. Differences between candidates and reference were more pronounced at higher PM concentrations. All optical instruments were affected by high RH and by the EC/OC ratio. Equations to convert candidate instruments data to FEM BAM type data are provided to enhance the usability of data from candidate instruments. This study tested the performance of seven candidate PM mass concentration measuring instruments in two settings - environmental chamber and field. The instruments were tested to determine their suitability for use during biomass combustion events and the effects of RH, PM mass concentrations, and concentrations of EC and OC on their performance. The accuracy and precision of each monitor and effect of RH, PM concentration, EC and OC concentrations are varied. The data show that most of these candidate instruments are suitable for measuring PM concentration during biomass combustions with a proper correction factor for each instrument type.
在美国西部，野火的频率和强度增加以及火灾季节延长，导致空气污染显著增加，包括 PM（空气动力学直径小于 2.5 µm 的颗粒物）浓度增加，这对附近社区的健康构成重大威胁。在野火期间，政府机构监测 PM 质量浓度，提供保护受影响社区所需的信息和行动；这需要连续测量仪器。本研究评估了七种候选仪器的性能：（1）Met One 环境衰减监测仪（EBAM），（2）Met One ES 型号 642（ES642），（3）Grimm 环境粉尘监测仪 164（EDM），（4）Thermo ADR 1500（ADR），（5）TSI DRX 型号 8543（DRX），（6）Dylos 1700（Dylos）和（7）Purple Air II（PA-II）与 BAM 1020（BAM）参考仪器相比。除了 EBAM 之外，所有候选仪器都使用光散射来确定 PM 质量浓度。我们的比较研究包括环境室和现场组件，每个候选仪器有两个运行在参考仪器旁边。 室内组件包括 6 天生物质燃烧排放的比较。现场组件涉及在空气监测站运行所有仪器 39.5 天，每小时平均相对湿度（RH）范围为 19%至 98%。目标是评估仪器的精度和准确性以及 RH、元素碳（EC）和有机碳（OC）浓度的影响。所有重复的候选仪器都显示出高小时相关性（R≥0.80）和更高的日平均相关性（R≥0.90），所有仪器与参考仪器的相关性都很好（R≥0.80）。DRX 和 Purple Air 将 PM 质量浓度高估了约两倍。在较高的 PM 浓度下，候选物与参考物之间的差异更为明显。所有光学仪器都受到高 RH 和 EC/OC 比值的影响。提供了将候选仪器数据转换为 FEM BAM 类型数据的方程，以增强对候选仪器数据的可用性。本研究在两个环境 - 环境室和现场中测试了七种候选 PM 质量浓度测量仪器的性能。对这些仪器进行了测试，以确定它们在生物质燃烧事件期间使用的适用性，以及 RH、PM 质量浓度以及 EC 和 OC 浓度对其性能的影响。每个监测器的准确性和精度以及 RH、PM 浓度、EC 和 OC 浓度的影响都有所不同。数据表明，这些候选仪器中的大多数都适用于测量生物质燃烧期间的 PM 浓度，并且每个仪器类型都需要适当的校正因子。
