Annual PM2.5 Concentrations for Countries and Urban Areas, 1998-2016

The Annual PM2.5 Concentrations for Countries and Urban Areas, 1998-2016, consists of mean concentrations of particulate matter (PM2.5) for countries and urban areas. The PM2.5 data are from the Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD) with GWR, 1998-2016. The urban areas are from the Global Rural-Urban Mapping Project, Version 1 (GRUMPv1): Urban Extent Polygons, Revision 02, and its time series runs from 1998 to 2016. The country averages are population-weighted such that concentrations in populated areas count more toward the country average than concentrations in less populated areas, and its time series runs from 2008 to 2015.

《各国及城市地区年度PM2.5浓度数据集（1998-2016）》收录了各国及城市地区颗粒物（PM2.5）的平均浓度数据。PM2.5数据源自MODIS、MISR和SeaWiFS气溶胶光学深度（AOD）的全球年度PM2.5网格数据，时间范围为1998至2016年。城市地区数据来源于全球农村-城市映射项目版本1（GRUMPv1）：城市范围多边形，修订版02，及其时间序列，运行时间为1998年至2016年。各国平均浓度以人口权重计算，即人口密集区域的浓度对国家平均浓度的贡献高于人口稀少区域的浓度，其时间序列数据运行时间为2008年至2015年。