State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China.
Sci Total Environ. 2019 Jun 15;669:362-376. doi: 10.1016/j.scitotenv.2019.02.180. Epub 2019 Mar 5.
China is the largest anthropogenic aerosol-generating country worldwide; however, few studies have analyzed the PM chemical components and their underlying precursor emissions over long periods and across the national domain. First, global 3-D tropospheric chemistry and transport model (GEOS-Chem)-integrated satellite-retrieved aerosol optical depth (AOD) and vertical profiles were used to estimate near-surface sulfate and nitrate levels at 10-km resolution over China from 2006 to 2014. Ground measurement validation of our satellite model yielded correlation coefficients (r) of 0.7 and 0.73 and normalized mean bias (NMB) values of -37.96% and - 32.73% for sulfate and nitrate, respectively. Second, analyses of the spatiotemporal distributions of sulfate and nitrate as well as the vertical density Ozone Monitoring Instrument (OMI)-measured SO (PBL_SO) and NO (TVCD_NO) indicated that the highest nitrate and sulfate levels occurred in the North China Plain (25 μg/m) and Sichuan Basin (SCB) (30 μg/m), respectively. The long-term variations in the estimated components and precursor gases indicated that the large sulfate decline was positively correlated with the SO emission reduction due to the mandatory desulfurization implemented in 2007. The annual growth rate of sulfate relative to the national mean was -6.19%/yr, and the concentration decreased by 17.10% from 2011 to 2014. Energy consumption increases and a lack of control measures for NO resulted in persistent increases in NO emissions and nitrate concentrations from 2006 to 2010, particularly in the SCB. With energy consumption structure advancements, reductions in NO emissions and corresponding nitrate levels over three typical regions were prominent after 2012. Third, the estimated national-scale uncertainties of satellite datasets at 0.1° × 0.1° were 26.88% for sulfate and 25.55% for nitrate. Differences in the spatial distributions and temporal trends between our estimated components and precursor gases were mainly attributed to the dataset accuracy, the data pre-processing strategy, inconsistent column density and near-surface mass concentration, meteorological variables and complex chemical reactions.
中国是世界上最大的人为气溶胶生成国；然而，很少有研究分析过 PM 化学组成及其潜在前体排放情况。首先，使用全球 3-D 对流层化学和传输模型（GEOS-Chem）集成的卫星反演气溶胶光学深度（AOD）和垂直廓线，估算了 2006 年至 2014 年中国 10 公里分辨率的近地表硫酸盐和硝酸盐水平。对我们卫星模型的地面测量验证得出，硫酸盐和硝酸盐的相关系数（r）分别为 0.7 和 0.73，归一化平均偏差（NMB）值分别为-37.96%和-32.73%。其次，硫酸盐和硝酸盐的时空分布以及臭氧监测仪（OMI）测量的 SO（PBL_SO）和 NO（TVCD_NO）的垂直密度分析表明，硝酸盐和硫酸盐的最高水平分别出现在华北平原（25μg/m）和四川盆地（SCB）（30μg/m）。估算成分和前体气体的长期变化表明，由于 2007 年强制脱硫，硫酸盐的大幅下降与 SO 排放减少呈正相关。相对于全国平均值，硫酸盐的年增长率为-6.19%/年，2011 年至 2014 年浓度下降了 17.10%。由于缺乏对 NO 的控制措施，能源消耗的增加导致 NO 排放和硝酸盐浓度持续增加，尤其是在 SCB。随着能源消费结构的进步，2012 年后三个典型区域的 NO 排放和相应硝酸盐水平的减少尤为明显。第三，在 0.1°×0.1°的卫星数据集的全国尺度不确定性估计值为硫酸盐的 26.88%和硝酸盐的 25.55%。我们估算的成分和前体气体的空间分布和时间趋势之间的差异主要归因于数据集的准确性、数据预处理策略、不一致的柱密度和近地表质量浓度、气象变量和复杂的化学反应。
