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Estimating PM 2.5 speciation concentrations using prototype 4.4 km-resolution MISR aerosol properties over Southern California
Atmospheric Environment ( IF 5 ) Pub Date : 2018-05-01 , DOI: 10.1016/j.atmosenv.2018.03.019
Xia Meng 1 , Michael J Garay 2 , David J Diner 2 , Olga V Kalashnikova 2 , Jin Xu 3 , Yang Liu 1
Affiliation  

Research efforts to better characterize the differential toxicity of PM2.5 (particles with aerodynamic diameters less than or equal to 2.5 μm) speciation are often hindered by the sparse or non-existent coverage of ground monitors. The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA’s Terra satellite is one of few satellite aerosol sensors providing information of aerosol shape, size and extinction globally for a long and continuous period that can be used to estimate PM2.5 speciation concentrations since year 2000. Currently, MISR only provides a 17.6 km product for its entire mission with global coverage every 9 days, a bit too coarse for air pollution health effects research and to capture local spatial variability of PM2.5 speciation. In this study, generalized additive models (GAMs) were developed using MISR prototype 4.4 km-resolution aerosol data with meteorological variables and geographical indicators, to predict ground-level concentrations of PM2.5 sulfate, nitrate, organic carbon (OC) and elemental carbon (EC) in Southern California between 2001 and 2015 at the daily level. The GAMs are able to explain 66%, 62%, 55% and 58% of the daily variability in PM2.5 sulfate, nitrate, OC and EC concentrations during the whole study period, respectively. Predicted concentrations capture large regional patterns as well as fine gradients of the four PM2.5 species in urban areas of Los Angeles and other counties, as well as in the Central Valley. This study is the first attempt to use MISR prototype 4.4 km-resolution AOD (aerosol optical depth) components data to predict PM2.5 sulfate, nitrate, OC and EC concentrations at the sub-regional scale. In spite of its low temporal sampling frequency, our analysis suggests that the MISR 4.4 km fractional AODs provide a promising way to capture the spatial hotspots and long-term temporal trends of PM2.5 speciation, understand the effectiveness of air quality controls, and allow our estimated PM2.5 speciation data to be linked with common spatial units such as census tract or zip code in epidemiological studies. This modeling strategy needs to be validated in other regions when more MISR 4.4 km data becoming available in the future.

中文翻译:

使用原型 4.4 公里分辨率 MISR 气溶胶特性估算南加州的 PM 2.5 形态浓度

为更好地表征 PM2.5(空气动力学直径小于或等于 2.5 μm 的颗粒)形态的差异毒性而进行的研究工作常常因地面监测器覆盖范围稀疏或不存在而受到阻碍。NASA Terra 卫星上的多角度成像光谱辐射计 (MISR) 是为数不多的能够长期、连续地提供全球气溶胶形状、大小和消光信息的卫星气溶胶传感器之一,可用于估计自 2000 年以来的 PM2.5 形态浓度目前,MISR 仅为其整个任务提供 17.6 公里的产品,每 9 天覆盖一次全球,对于空气污染健康影响研究和捕捉 PM2.5 形态的局部空间变异来说有点太粗糙。在本研究中,使用 MISR 原型 4.4 公里分辨率气溶胶数据以及气象变量和地理指标开发了广义加性模型 (GAM),以预测 PM2.5 硫酸盐、硝酸盐、有机碳 (OC) 和元素碳的地面浓度(EC) 2001 年至 2015 年间南加州的日常水平。GAM 能够分别解释整个研究期间 PM2.5 硫酸盐、硝酸盐、OC 和 EC 浓度每日变化的 66%、62%、55% 和 58%。预测浓度捕捉了洛杉矶和其他县以及中央山谷城市地区四种 PM2.5 物种的大区域模式和精细梯度。本研究首次尝试使用MISR原型4.4公里分辨率AOD(气溶胶光学深度)成分数据来预测次区域尺度的PM2.5硫酸盐、硝酸盐、OC和EC浓度。尽管时间采样频率较低,但我们的分析表明,MISR 4.4 km 分数 AOD 提供了一种有前途的方法来捕获 PM2.5 形态的空间热点和长期时间趋势,了解空气质量控制的有效性,并允许我们估计的 PM2.5 形态数据与流行病学研究中的人口普查区或邮政编码等常见空间单位相关联。当未来有更多 MISR 4.4 km 数据可用时,该建模策略需要在其他地区得到验证。
更新日期:2018-05-01
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