How Does the National Intellectual Property Strong County Program Improve County-Level Air Quality? Evidence from Chinese Counties

Intellectual property protection systems play a critical role in fostering technological innovation, and their potential influence on environmental governance warrants further exploration. This paper utilizes data from 2607 counties in China spanning from 2000 to 2022 and employs the Multiple Timepoint Difference-in-Differences (MT-DID) model to investigate the impact of the National Intellectual Property Strong County Program (NIPSC) on air quality at the county level. The results reveal that NIPSC contributes to reducing SO2 and NH3 concentrations, highlighting the positive role of intellectual property protection policies in enhancing environmental quality. Further mechanism analysis shows that NIPSC effectively reduces pollution emissions through mechanisms such as fostering technological innovation, upgrading industrial structures, and promoting economic agglomeration. Heterogeneity analysis indicates that the NIPSC policy yields more pronounced improvements in air quality in regions that are not traditional industrial bases, possess international airports, or hold higher administrative status. This study offers a novel analytical perspective on county-level air pollution governance and presents new empirical evidence on the relationship between the NIPSC policy and environmental governance.