As part of the United States Environmental Protection Agency’s 2010 Nitrogen Dioxide (NO₂) National Ambient Air Quality Standards (NAAQS) review, a national network of near-road sites was established to characterize pollutant behavior, interaction, and dispersion in the ambient near-road environment. Using spatial interpolation to estimate the near-road concentration increments of NO₂ and particulate matter with an aerodynamic diameter of 2.5 μm and less (PM_2.5) relative to nearby non-near-road monitors, we found that the 2013–2018 national average increment is 6.9 ppb and 1.0 μg m^–3 for NO₂ and PM_2.5, respectively. Analyses of the hourly near-road NO₂, nitric oxide (NO), and PM_2.5 increments showed distinct diurnal cycles; the NO₂ increment peaks at ∼9 ppb during the early afternoon (2–4 pm local time) while the NO and PM_2.5 increments peak during the morning rush hour (5–8 am local time) at 25 ppb and 1.8 μg m^–3 for NO and PM_2.5, respectively. Although long-term trends are not yet available for this network of sites, a similar analysis of the NO₂ and PM_2.5 increment at a quasi-near-road site outside of the official network in Elizabeth, NJ showed gradual decreases in the increment over time since the mid-2000s.

中文翻译：

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使用国家近路监测网络对美国主要公路附近的氮氧化物和细颗粒物进行表征

作为美国环境保护局2010年二氧化氮（NO ₂）国家环境空气质量标准（NAAQS）审查的一部分，建立了一个全国性的近道路站点网络，以表征污染物行为，相互作用和在附近环境中的扩散。道路环境。使用空间插值法估算相对于附近的非道路监测器，空气动力直径为2.5μm及以下（PM _2.5）的NO ₂和颗粒物在道路附近的浓度增量，我们发现2013–2018年全国平均增量对于NO ₂和PM _2.5分别为6.9 ppb和1.0μgm ^-3。每小时近距离NO _2的分析，一氧化氮（NO）和PM _2.5增量显示出明显的昼夜循环；NO _2的增量在午后（当地时间2-4 pm）约9 ppb达到峰值，而NO和PM _2.5的峰值在高峰时间（当地时间上午5-8）在25 ppb和1.8μgm时达到峰值^{– 3}为NO和PM _2.5分别。尽管该站点网络尚无长期趋势，但对新泽西州伊丽莎白市官方网络外部的准近距离站点的NO ₂和PM _2.5增量进行的类似分析表明，该增量逐渐减小。时间从2000年代中期开始。