Rural lower Yakima Valley, Washington is home to the reservation of the Confederated Tribes and Bands of the Yakama Nation, and is a major agricultural region. Episodic poor air quality impacts this area, reflecting sources of particulate matter with a diameter of less than 2.5 micrometers (PM2.5) that include residential wood smoke, agricultural biomass burning and other emissions, truck traffic, backyard burning, and wildfire smoke. University of Washington partnered with the Yakama Nation Environmental Management Program to investigate characteristics of PM2.5 using 9 months of data from a combination of low-cost optical particle counters and a 5-wavelength aethalometer (MA200 Aethlabs) over 4 seasons and an episode of summer wildfire smoke. The greatest percentage of hours sampled with PM2.5 >12 μg/m3 occurred during the wildfire smoke episode (59%), followed by fall (23%) and then winter (21%). Mean (SD) values of Delta-C (μg/m3), which has been posited as an indicator of wood smoke, and determined as the mass absorbance difference at 375-880nm, were: summer - wildfire smoke 0.34 (0.52), winter 0.27 (0.32), fall 0.10 (0.22), spring 0.05 (0.11), and summer - no wildfire smoke 0.04 (0.14). Mean (95% confidence interval) values of the absorption Ångström exponent, an indicator of the wavelength dependence of the aerosol, were: winter 1.5 (1.2-1.8), summer - wildfire smoke 1.4 (1.0-1.8), fall 1.3 (1.1-1.4), spring 1.2 (1.1-1.4), and summer - no wildfire smoke 1.2 (1.0-1.3). The trends in Delta-C and absorption Ångström exponents are consistent with expectations that a higher value reflects more biomass burning. These results suggest that biomass burning is an important contributor to PM2.5 in the wintertime, and emissions associated with diesel and soot are important contributors in the fall; however, the variety of emissions sources and combustion conditions present in this region may limit the utility of traditional interpretations of aethalometer data. Further understanding of how to interpret aethalometer data in regions with complex emissions would contribute to much-needed research in communities impacted by air pollution from agricultural as well as residential sources of combustion.

中文翻译：

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使用低成本 PM 监测器和多波长风化仪来表征 Yakama Nation 保留区中的 PM2.5

华盛顿州亚基马山谷下游农村是亚卡马民族联盟部落和部落保留地的所在地，是一个主要的农业区。偶发性差空气质量影响该地区，反映直径小于 2.5 微米 (PM2.5) 的颗粒物来源，包括住宅木材烟雾、农业生物质燃烧和其他排放物、卡车交通、后院燃烧和野火烟雾。华盛顿大学与 Yakama Nation 环境管理计划合作，使用来自低成本光学粒子计数器和 5 波长风化计 (MA200 Aethlabs) 组合的 9 个月数据调查 PM2.5 的特征，该数据超过 4 个季节和一集夏季野火烟雾。PM2.5 采样的最大小时数百分比 > 12 μg/m3 发生在野火烟雾事件期间 (59%)，其次是秋季 (23%)，然后是冬季 (21%)。Delta-C (μg/m3) 的平均 (SD) 值已被假定为木材烟雾的指标，并确定为 375-880nm 处的质量吸光度差异：夏季 - 野火烟雾 0.34 (0.52)，冬季0.27 (0.32)、秋季 0.10 (0.22)、春季 0.05 (0.11) 和夏季 - 无野火烟雾 0.04 (0.14)。吸收 Ångström 指数的平均（95% 置信区间）值是气溶胶波长依赖性的指标：冬季 1.5 (1.2-1.8)，夏季 - 野火烟雾 1.4 (1.0-1.8)，秋季 1.3 (1.1- 1.4)、春季 1.2 (1.1-1.4) 和夏季 - 无野火烟雾 1.2 (1.0-1.3)。Delta-C 和吸收 Ångström 指数的趋势与预期值一致，即较高的值反映更多的生物质燃烧。这些结果表明，冬季生物质燃烧是 PM2.5 的重要贡献者，而与柴油和烟尘相关的排放是秋季的重要贡献者；然而，该地区存在的各种排放源和燃烧条件可能会限制对风速计数据进行传统解释的效用。进一步了解如何解释排放复杂地区的空气流量计数据将有助于在受农业和住宅燃烧源空气污染影响的社区开展急需的研究。该地区存在的各种排放源和燃烧条件可能会限制对风速计数据进行传统解释的效用。进一步了解如何解释排放复杂地区的空气流量计数据将有助于在受农业和住宅燃烧源空气污染影响的社区开展急需的研究。该地区存在的各种排放源和燃烧条件可能会限制对风速计数据进行传统解释的效用。进一步了解如何解释排放复杂地区的空气流量计数据将有助于在受农业和住宅燃烧源空气污染影响的社区开展急需的研究。