Spatial mismatch between pollutant emission and environmental quality in China - A case study of NOx

Although pollutant emission is the main cause of environmental quality deterioration, regional environmental quality may not be consistent with pollutant emission volume. To investigate the relationship between environmental quality and pollutant emission in Chinese provinces, a spatial mismatch index model and a barycenter model were established. NOx emissions and NO2 concentrations for the period 2006-2012 were used to verify the models. Results showed that regional differences in emission intensity were found; total NOx emissions for the nine highest-emission provinces accounted for 61.7% of the national total. Spatial distributions of NO2 pollution remained stable. Areas below Grade II of the National Ambient Air Quality Standard (GB 3095-2012) were mainly in the eastern coastal region, especially the Yangtze River Delta, Pearl River Delta, and Beijing-Tianjin-Hebei area. Spatial mismatches could be found between NOx emission and NO2 concentration, with the spatial mismatch index ranging 29.6-32.7, while barycenter distance for these two variables ranged 45.4-138.5 km. Spatial mismatches between NOx emission and NO2 concentration have decreased gradually over time. Our findings enhance understanding of the link between environmental quality and pollutant emission and should be taken into account when establishing regional environmental goals.