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 PM2.5 (particulate matter <2.5 µm in aerodynamic diameter) that pose significant health risks to nearby communities. During wildfires, government agencies monitor PM2.5 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 PM2.5 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 (R2 ≥ 0.80) and higher daily average correlations (R2 ≥ 0.90), where all instruments correlated well (R2 ≥ 0.80) with the reference. The DRX and Purple Air overestimated PM2.5 mass concentrations by a factor of ~two. Differences between candidates and reference were more pronounced at higher PM2.5 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.Implications: This study tested the performance of seven candidate PM2.5 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 PM2.5 concentration during biomass combustions with a proper correction factor for each instrument type.

中文翻译：

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实时和接近实时的PM2.5烟雾监测器的实验室和现场评估。

美国西部大火的发生频率和强度增加，火季延长，导致空气污染显着增加，其中包括PM2.5的浓度（空气动力学直径中的颗粒物<2.5 µm），对附近居民构成重大健康风险社区。在野火期间，政府机构监视PM2.5的质量浓度，提供保护受影响社区所需的信息和行动；这就需要不断测量仪器。这项研究评估了七种候选仪器的性能：（1）Met One环境Beta衰减监视器（EBAM），（2）Met One ES模型642（ES642），（3）Grimm环境粉尘监视器164（EDM），（4） Thermo ADR 1500（ADR），（5）TSI DRX型号8543（DRX），（6）Dylos 1700（Dylos），（7）紫色空气II（PA-II）与BAM 1020（BAM）参考仪器的比较。除EBAM外，所有候选对象均使用光散射来确定PM2.5质量浓度。我们的比较研究包括环境舱和现场组件，每个候选仪表中有两个在参​​考仪表旁运行。燃烧室组件需要进行6天的生物质燃烧排放比较。现场组件涉及在空气监测站中操作所有仪器39.5天，每小时平均相对湿度（RH）为19％至98％。目的是评估仪器的精度和准确性以及相对湿度，元素碳（EC）和有机碳（OC）浓度的影响。所有重复的候选仪器均显示出较高的小时相关性（R2≥0。80）和更高的每日平均相关性（R2≥0.90），其中所有仪器与参考的相关性都很好（R2≥0.80）。DRX和Purple Air将PM2.5的质量浓度高估了约两倍。在较高的PM2.5浓度下，候选者与参考者之间的差异更为明显。所有光学仪器都受到较高的相对湿度和EC / OC比的影响。提供了将候选仪器数据转换为FEM BAM类型数据的方程式，以增强来自候选仪器数据的可用性。启示：本研究在环境（环境）箱和现场两种环境下测试了七种候选PM2.5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过程中的适用性以及相对湿度，PM质量浓度，EC和OC对其性能的关注程度。每个监视器的精度和精确度以及相对湿度，PM浓度，EC和OC浓度的影响都不同。数据表明，大多数候选仪器都适合在生物质燃烧过程中测量PM2.5浓度，并且每种仪器类型都有适当的校正系数。