J Air Waste Manag Assoc. 2014 Mar;64(3):349-59. doi: 10.1080/10962247.2013.863814.
Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, members of a subset of compounds are considered high priority due to their significant contribution to cancer and noncancer health risks and the contribution of mobile sources to total exposure as evaluated by the U.S. Environmental Protection Agency (EPA) National-Scale Air Toxics Assessments (NATA). These pollutants include benzene, 1,3-butadiene, ethylbenzene, acrolein, acetaldehyde, formaldehyde, naphthalene, polycyclic organic matter, and diesel particulate matter/organic gases. This study provided year-long trends of benzene, 1,3-butadiene, acrolein, acetaldehyde, and formaldehyde in Las Vegas, NV Results indicated that MSAT concentrations often did not exhibit trends typical of other primary emitted pollutants in this study. Instead, other mobile sources beyond the highway of interest contributed to the measured values, including a major arterial road, a large commercial airport, and a nearby parking lot. The data were compared with relevant census-tract NATA estimates, with estimated ambient 1,3-butadiene concentrations similar to the measured values. Measured benzene values were much lower relative to the NATA total ambient benzene concentrations. Measured acrolein values were much higher relative to the NATA total acrolein concentrations. Measured acetaldehyde and formaldehyde values were also higher relative to the NATA total acetaldehyde and formaldehyde concentrations for all wind conditions and downwind conditions. Some possible explanations for these differences include nearby sources influencing the measured values; meteorological influences that may not be well captured by the NATA modeling regime; chemical reactivity of measured compounds; and additional explanatory variables may be needed for certain urban areas in order to accurately disaggregate anthropogenic air toxics emissions.
Comparison of air toxics concentrations measured at four long-term near-road sites in Las Vegas, NV, show generally good agreement with the EPA 2005 NATA total ambient concentrations. Measured concentrations did not compare as well with EPA 2005 NATA for the on-road mobile portion of the ambient concentrations. This highlights the complexity of air toxic emission sources and impacts in urban areas, especially around large highway facilities; NATA's inability to capture local-scale meteorology and fine-scale ambient gradients; and that additional explanatory variables may be needed for certain urban areas in order to accurately disaggregate anthropogenic air toxics emissions.
移动源空气毒物（MSAT）的暴露与许多不良健康影响有关。虽然移动源排放了数千种空气毒物化合物，但由于其对癌症和非癌症健康风险的显著贡献，以及美国环境保护署（EPA）国家规模空气毒物评估（NATA）评估的移动源对总暴露的贡献，某些化合物亚组的成员被认为是高优先级。这些污染物包括苯、1,3-丁二烯、乙苯、丙烯醛、乙醛、甲醛、萘、多环有机物和柴油颗粒物/有机气体。本研究提供了内华达州拉斯维加斯一年来苯、1,3-丁二烯、丙烯醛、乙醛和甲醛的趋势。结果表明，MSAT 浓度通常没有表现出本研究中其他主要排放污染物的典型趋势。相反，除了研究中感兴趣的高速公路外，其他移动源也对测量值做出了贡献，包括一条主要的动脉道路、一个大型商业机场和附近的停车场。这些数据与相关的人口普查区 NATA 估计值进行了比较，估计的环境 1,3-丁二烯浓度与测量值相似。测量的苯值相对 NATA 总环境苯浓度要低得多。测量的丙烯醛值相对 NATA 总丙烯醛浓度要高得多。在所有风和下风条件下，测量的乙醛和甲醛值也相对 NATA 总乙醛和甲醛浓度要高。这些差异的一些可能解释包括附近的源对测量值的影响；NATA 建模机制可能无法很好地捕捉到的气象影响；测量化合物的化学反应性；以及某些城市地区可能需要额外的解释变量，以便准确地将人为空气毒物排放进行细分。
在内华达州拉斯维加斯四个长期近路点测量的空气毒物浓度与 EPA 2005 NATA 总环境浓度基本一致。与 EPA 2005 NATA 相比，测量的浓度与环境浓度的道路部分不太相符。这突出了城市地区空气毒物排放源和影响的复杂性，尤其是在大型公路设施周围；NATA 无法捕捉到局部尺度的气象和细尺度的环境梯度；以及某些城市地区可能需要额外的解释变量，以便准确地将人为空气毒物排放进行细分。
