On May 6, 2024, Professor Yazhen Gong from the School of Ecology & Environment at Renmin University of China, along with collaborators Professor Ke Chen from Shenyang Agricultural University and Professor Jinhua Zhao from Cornell University, published their research entitled "Are facemasks effective against particulate matter pollution? Evidence from the field" in the Journal of Environmental Economics and Management (JEEM), a leading journal in resource and environmental economics. All three authors share co-first authorship, with Professors Gong and Zhao serving as corresponding authors. Notably, this represents Professor Gong's second publication in JEEM.

PM2.5 pollution poses significant health risks. Reducing outdoor activity and using protective masks on high-pollution days are considered effective measures with important welfare implications. However, consensus on the protective effectiveness of mask-wearing remains absent within both media and academic communities, domestically and internationally. This study addresses this gap by conducting a large-scale randomized intervention experiment and a five-month follow-up survey, involving 2,296 residents from 40 communities in Shenyang from November 2018 to March 2019 (prior to the Covid-19 pandemic). Econometric modeling analysis yielded the following findings: first, the protective masks used by respondents in daily lives achieved an overall efficiency of 80% in reducing doctor visits related to respiratory or cardiovascular diseases; second, the health benefits gained from mask-wearing significantly surpass the associated costs, highlighting their substantial welfare implications.

The primary contribution of this research lies in its robust findings derived from large-scale field experiments and longitudinal tracking surveys that capture daily mask-wearing behavior and outdoor activity durations among respondents. These findings hold critical policy implications: it is essential for government and relevant agencies to to provide clear, evidence-based guidance on the use of anti-smog masks as personal protection measure against PM pollution. Such communication can encourage residents to adopt protective measures, mitigating health risks associated with smog exposure and ultimately enhancing social welfare.

This article is one of the key outputs from the National Natural Science Foundation of China project titled "Research on the Influencing Factors of Residents' Adoption of Anti-Smog Protective Measures: Empirical Analysis Based on Survey and Experimental Methods" (grant No: 71773135), jointly led by Professors Gong and Zhao. The project was rated as excellent at the performance evaluation conducted by the Department of Management Science of the National Natural Science Foundation Committee in 2024.

Full text link: Journal of Environmental Economics and Management (https://www.sciencedirect.com/science/article/pii/S0095069624000755?via%3Dihub#fig4)