Has the healthy city pilot policy improved urban air quality in China? Evidence from a quasi-natural experiment

Air pollution has caused serious consequences, and improving air quality has become a major global challenge. The environmental improvement of a healthy city is widely recognized, but quantitative assessment of its effect is still relatively rare. In the context of the “Healthy China” strategy, this paper considers the healthy city pilot (HCP) policy in China as a “quasi-natural experiment.” Based on the panel data of 288 prefecture-level cities from 2009 to 2020, a difference-in-differences strategy is used to examine the effect of the HCP policy on urban air quality. Our results show that the HCP policy effectively decreases PM2.5 by 6.8%, dust by 6.0%, SO2 by 2.4%, and CO2 emissions per capita by 8.8%. The findings continue to hold after a series of robustness tests. Mechanism analysis shows that the HCP policy significantly decreases industry pollutant discharge, increases city innovation, promotes efficient energy use and transformation, and improves public transport system and green infrastructure. These mechanisms play an important role in improving air quality. Furthermore, the HCP policy greatly improved air quality in regions with substantial populations, low financial pressure, high Internet development, and medical levels. In summary, the government must review the results of implementing the HCP policy and incrementally expand the number of healthy cities. Increasing the weighting of air quality in policy assessment and strictly implementing a mechanism that combines incentives and disincentives.