Research on the spatiotemporal characteristics and influencing factors of environmental emergency incidents in China in recent decades can improve the effectiveness and accuracy of risk supervision of environmental emergency incidents. Based on the data of environmental emergency incidents in 31 provincial regions in China from 1991 to 2018, this study used spatial autocorrelation analysis and a geographically and temporally weighted regression model to analyze the spatial dependence of environmental emergency incidents and the temporal and spatial heterogeneity of influencing factors. The results showed that: ① there was a significant positive spatial correlation between environmental emergency incidents during 1991-1994 and 2001-2014, and the spatial agglomeration was gradually increasing, that is, environmental emergency incidents existed in the provinces of China; clearly, the space depended on the characteristics and was not completely random. ② There was an unbalanced development pattern of environmental emergency incidents in China. The provinces with "L-L" agglomeration were concentrated in the western and northeastern regions, and the number increased and then decreased; by contrast, the ones with "H-H" agglomeration shifted from the east and south to the central and western regions, and the number increased following the decrease. The role of environmental emergency incident in different provincial regions in the spatial agglomeration was different and constantly changing. ③ The effects of various influencing factors on environmental emergency incidentshad obvious temporal and spatial heterogeneity in different periods and different provinces. The impact of the level of economic development on environmental emergency incidents was shown as a "negative-positive-negative" pattern. The impact of industrial structure on environmental emergency incidents was shown as a "negative-positive" pattern. The overall impact of pollution emissions on environmental emergency incident presented a "positive-negative-positive" pattern. Environmental letters and visits had a positive impact on the occurrence of environmental emergency incidents. The negative impact of the legal environment on environmental emergency incidents was gradually weakening. The negative impact of pollution control on environmental emergency incidents at the provincial level has gradually become apparent.
Keywords: China; environmental emergency incident; geographically and temporally weighted regression; influencing factors; spatial autocorrelation; spatiotemporal heterogeneity.