College of Resources and Environment, Huazhong Agricultural University, Wuhan, China.
Department of Geography and Resource Management, The Chinese University of Hong Kong, Hong Kong.
Environ Pollut. 2019 Feb;245:616-626. doi: 10.1016/j.envpol.2018.11.001. Epub 2018 Nov 8.
China has performed crop residue burning (CRB) for a long time and has suffered from resultant environmental pollution. High temporal resolution has not been fully discussed in attempts to address the temporal and spatial impact of CRB in China on air quality. Our study used the MOD14A1 product of the MODerate resolution Imaging Spectrometer (MODIS) to extract the daily CRB for China during the period from 2014 to 2016, and the daily aerosol optical depth (AOD) provided by MODIS Collection 6 was obtained to simultaneously reflect the air pollution. First, the study area was classified into five subregions. A temporal analysis was conducted on the daily variation in the number of CRB events and the regional mean value of AOD, the spatial contribution ratio of CRB on aerosol pollution was then calculated, and finally, a temporal and spatial Pearson correlation was calculated to find the spatially varying relationship between CRB and aerosol. The results suggest the following: (1) CRB possesses seasonal characteristics that are associated with the harvest time or sowing time of major crops in the region. (2) The impact of CRB on aerosol was delayed by 1-6 days. (3) High contribution ratios (70%-90%) occurred in northeast China on a large scale; even when the impact of the CRB on aerosol pollution in the Huang-Huai-Hai river basin occurred on a large scale, the value was merely approximately 30%. Relatively low contributions of CRB have been found in other places, whereas the contribution of CRB was severe in some places with high-density populations. (4) Temporal-spatial correlation provided an accurate index to reflect the correlation of CRB and aerosol in a specific location, which suggests that, in places with large scale and dense CRB, CRB tends to have a high positive correlation with aerosol pollution for each day.
中国长期以来一直进行秸秆焚烧（CRB），因此遭受了环境污染。在试图解决中国 CRB 对空气质量的时空影响时，高时间分辨率尚未得到充分讨论。我们的研究使用 MODIS 的 MOD14A1 产品提取了 2014 年至 2016 年期间中国的每日 CRB，并获得了 MODIS 集合 6 提供的每日气溶胶光学深度（AOD），以同时反映空气污染。首先，将研究区域分为五个子区域。对 CRB 事件的日变化和 AOD 的区域平均值进行了时间分析，然后计算了 CRB 对气溶胶污染的空间贡献比，最后计算了时间和空间 Pearson 相关性，以发现 CRB 和气溶胶之间的空间变化关系。结果表明：（1）CRB 具有季节性特征，与该地区主要作物的收获或播种时间有关。（2）CRB 对气溶胶的影响滞后 1-6 天。（3）大规模的东北地区出现高贡献率（70%-90%）；即使在黄淮海流域发生大规模 CRB 对气溶胶污染的影响时，其值也仅约为 30%。在其他地方发现相对较低的 CRB 贡献，而在人口密度较高的某些地方，CRB 的贡献则很严重。（4）时空相关性提供了一个准确的指标来反映特定位置的 CRB 和气溶胶的相关性，这表明在具有大规模和密集 CRB 的地方，CRB 每天与气溶胶污染的相关性往往很高。
