城市蔓延、私人交通与雾霾污染

本文选取中国280个地级市2009—2018年的面板数据为研究样本，探究城市蔓延与雾霾污染之间的作用机制。以私人交通为门槛变量，考察城市蔓延对雾霾污染的门槛效应。研究结果表明：(1)城市蔓延对雾霾污染的影响呈现出先降后升的U形曲线特点；(2)私人交通对雾霾污染的影响表现为倒U形的曲线特征，即随着私人交通发展水平的提高，雾霾污染呈现先增后减的趋势；(3)城市蔓延对雾霾污染的影响存在双重门槛效应，当私人交通的门槛值小于第一个门槛值(e^11.6130=110 525辆)时，城市蔓延会加剧雾霾污染；当私人交通的门槛值介于第一个门槛值和第二个门槛值(e^12.2473=208 417辆)之间时，城市蔓延对雾霾污染的影响系数为正，但未通过显著性检验；当私人交通跨过第二个门槛值时，城市蔓延水平的提高有助于抑制雾霾污染。研究城市蔓延、私人交通与雾霾污染这三者之间的关系对于促进城市的健康可持续发展具有重要的意义。

Urban Sprawl, Private Traffic and Haze Pollution

The panel data of 280 prefecture-level cities in China from 2009 to 2018 were selected as the research samples to explore the mechanism of urban sprawl and haze pollution. Taking private traffic as threshold variable, the threshold effect of urban sprawl on haze pollution was investigated. The research results showed that the impact of urban sprawl on haze pollution presented a U-shaped curve of first decline and then rise; The influence of private traffic on haze pollution showed an inverted U-shaped curve, that is, with the improvement of private traffic development level, haze pollution showed a trend of increasing first and then decreasing; There was a double threshold effect of urban sprawl on haze pollution. When the threshold value of private traffic was less than the first threshold value (e^11.6130=110 525 vehicles), urban sprawl aggravated haze pollution. When the threshold of private traffic was between the first threshold and the second threshold (e^12.2473=208 417 vehicles), the influence coefficient of urban sprawl on haze pollution was positive, but it did not pass the significance test. When private transport crossed the second threshold, higher levels of urban sprawl helped curb haze pollution. Studying the relationship among urban sprawl, private traffic and haze pollution is of great significance for promoting the healthy and sustainable development of cities.