Professor Ning Zhang publishes two articles on air pollution

Professor Ning Zhang, Senior Departmental Fellow at the Department of Land Economy, has published two articles on air pollution.

One of the articles was published in the prestigious journal Environmental and Resource Economics. It examines the causal effect of air pollution on firm innovation based on a nationwide sample of Chinese manufacturing firms, and is entitled “Firm Innovation in Hazy Days: Chinese Evidence”.

The abstract reads as follows:

This paper estimates the causal effect of air pollution on firm innovation based on a nationwide sample of Chinese manufacturing firms. Using thermal inversion as instrument variable (IV), we demonstrate that air pollution significantly hurts firm innovation performance: a 1% increase in air pollution (PM2.5) in the past year, from its mean value, amounts to a 1.5% decrease in the number of invention patents compared to the average between 1999 and 2013. We also provide the casual estimate using regression discontinuity design (RDD) by exploiting the exogenous variation in pollution level caused by China’s Huai River policy: the decrease in firms’ invention patents is approximately 2.2% in the regions north of the Huai River Line. The underlying mechanism analyses reveal that poor air quality has detrimental effects on labor productivity, firms’ human capital accumulation, and financing ability. These findings highlight the substantial costs associated with air pollution, which are greater than previously thought, as it hinders innovation, a crucial driver of long-term economic growth.

Thanks to the University of Cambridge for supporting the Open Access publication of this paper.

The second article was published in the Cell Press journal iScience. This article delves into the causal effect of air pollution on eye and ear health in China, elucidating the underlying mechanisms.

The article is entitled “Uncovering the impact and mechanisms of air pollution on eye and ear health in China”.

The abstract reads as follows:

Increasing air pollution could undermine human health, but the causal link between air pollution and eye and ear health has not been well-studied. Based on four-week-level records of eye and ear health over 1991-2015 provided by the China Health and Nutrition Survey, we estimate the causal effect of air pollution on eye and ear health. Using two-stage least squares estimation, we find that eye or ear disease possibility rises 1.48% for a 10 μg/m3 increase in four-week average PM2.5 concentration. The impacts can last about 28 weeks and will be insignificant afterward. Females, individuals aged 60 years and over, with high exposure environments, relatively poor economic foundations, and low knowledge levels are more vulnerable to such negative influences. Behavioral channels like more smoking activities and less sleeping activities could partly explain this detrimental effect. Our findings enlighten how to minimize the impact of air pollution and protect public health.