Are Small Cities More Environmentally Friendly? An Empirical Study from China

Area of Science:

• Environmental Science
• Urban Planning
• Economics

Background:

• Rapid urbanization in China exacerbates air pollution challenges.
• Fine particulate matter (PM2.5) is a major urban air pollutant.
• Understanding the relationship between city size and PM2.5 is crucial for effective environmental policy.

Purpose of the Study:

• To investigate the correlation between PM2.5 concentrations and city size in China.
• To analyze the long-term trends and potential inflection points in this relationship.
• To test the validity of the Environmental Kuznets Curve (EKC) and Pollution Haven Hypothesis (PHH).

Main Methods:

• Utilized panel data from 278 Chinese cities spanning 2007-2016.
• Employed static and dynamic panel models within the STIRPAT (Stochastic Impacts by Regression on Population, Affluence and Technology) framework.
• Analyzed the non-linear relationship between city size and PM2.5 levels.

Main Results:

• A significant inverted N-shaped correlation was identified between PM2.5 and city size.
• Two critical inflection points were observed at population sizes of 949,200 and 3,736,100.
• The study found no support for the EKC hypothesis but provided evidence for the PHH.

Conclusions:

• The complex relationship between PM2.5 and city size is expected to persist.
• Controlling city size may not be necessary for cities exceeding the second inflection point.
• Cities experiencing population growth face significant pressure to mitigate PM2.5 pollution.