Center for Human Geography and Urban Development, School of Geography and Remote Sensing, Guangzhou University, Guangzhou, 510006, China.
Guangdong Provincial Center for Urban and Migration Studies, Guangzhou, 510006, China.
BMC Public Health. 2024 May 4;24(1):1234. doi: 10.1186/s12889-024-18671-y.
"National Civilized City" (NCC) is regarded as China's highest honorary title and most valuable city brand. To win and maintain the "golden city" title, municipal governments must pay close attention to various key appraisal indicators, mainly environmental ones. In this study we verify whether cities with the title are more likely to mitigate SO pollution. We adopt the spatial Durbin difference-in-differences (DID) model and use panel data of 283 Chinese cities from 2003 to 2018 to analyze the local (direct) and spillover effects (indirect) of the NCC policy on SO pollution. We find that SO pollution in Chinese cities is not randomly distributed in geography, suggesting the existence of spatial spillovers and possible biased estimates. Our study treats the NCC policy as a quasi-experiment and incorporates spatial spillovers of NCC policy into a classical DID model to verify this assumption. Our findings show: (1) The spatial distribution of SO pollution represents strong spatial spillovers, with the most highly polluted regions mainly situated in the North China Plain. (2) The Moran's I test results confirms significant spatial autocorrelation. (3) Results of the spatial Durbin DID models reveal that the civilized cities have indeed significantly mitigated SO pollution, indicating that cities with the honorary title are acutely aware of the environment in their bid to maintain the golden city brand. As importantly, we notice that the spatial DID term is also significant and negative, implying that neighboring civilized cities have also mitigated their own SO pollution. Due to demonstration and competition effects, neighboring cities that won the title ostensibly motivates local officials to adopt stringent policies and measures for lowering SO pollution and protecting the environment in competition for the golden title. The spatial autoregressive coefficient was significant and positive, indicating that SO pollution of local cities has been deeply affected by neighbors. A series of robustness check tests also confirms our conclusions. Policy recommendations based on the findings for protecting the environment and promoting sustainable development are proposed.
“全国文明城市”（NCC）被视为中国的最高荣誉称号和最有价值的城市品牌。为了赢得并保持“金牌城市”的称号，市政府必须密切关注各种关键的评估指标，主要是环境指标。在这项研究中，我们验证了拥有该称号的城市是否更有可能减轻 SO 污染。我们采用空间 Durbin 差分（DID）模型，利用 2003 年至 2018 年中国 283 个城市的面板数据，分析了 NCC 政策对 SO 污染的本地（直接）和溢出效应（间接）。我们发现，中国城市的 SO 污染在地理上并非随机分布，这表明存在空间溢出效应，可能存在有偏估计。我们将 NCC 政策视为一项准实验，并将 NCC 政策的空间溢出效应纳入经典 DID 模型进行验证。研究结果表明：（1）SO 污染的空间分布呈现出强烈的空间溢出效应，污染最严重的地区主要位于华北平原。（2）Moran's I 检验结果证实了显著的空间自相关。（3）空间 Durbin DID 模型的结果表明，文明城市确实显著减轻了 SO 污染，这表明这些城市在争取保持金牌城市品牌的过程中，对环境问题有着强烈的意识。同样重要的是，我们注意到空间 DID 项也是显著的负项，这意味着获得荣誉称号的邻近城市也减轻了自身的 SO 污染。由于示范和竞争效应，获得称号的邻近城市显然会促使当地官员采取更严格的政策和措施来降低 SO 污染，以保护环境，在竞争金牌称号时实现可持续发展。空间自回归系数显著为正，表明当地城市的 SO 污染受到邻居的深刻影响。一系列稳健性检验也证实了我们的结论。根据研究结果，提出了保护环境和促进可持续发展的政策建议。
