Journal Article

The influence of mixed environmental air pollution on deliberate self-harm among university students: evidence from 20 cities in China

Yang, Tingzhong, Cottrell, Randall R., Jiang, Shuhan, Peng, Sihui

2025

Overview

Background While people are exposed to various air pollutants, limited research exists on the combined effects of multiple pollutants on mental health, and no studies have explored the social and behavioral mechanisms of mental health issues in real-world settings. This study aimed to evaluate the association between mixed air pollutants and deliberate self-harm (DSH), as well as the potential social and behavioral mechanisms underlying these associations. Methods The study involved 5,025 university students, selected through a multistage survey sampling process from 22 universities in 20 cities. Participants provided information on socioeconomic characteristics and DSH via a standardized questionnaire. Regional socioeconomic status and air pollution data were obtained from a national database. Multilevel logistic regression models were used to assess the association between mixed air pollution and DSH, and a structural equation model was used to explore underlying social mechanisms. Results The multilevel logistic regression model revealed that the mixed air pollution index, exposure to secondhand smoke (SHS), and the number of air pollution days were significantly associated with the likelihood of DSH, with odds ratios (OR) of 2.78 (95% CI: 1.22, 6.31) and 3.30 (95% CI: 1.67, 6.52), respectively. Significant quantitative correlations were found between the number of air pollution days and the likelihood of DSH (r = 0.5553, p < 0.0001). Structural equation modeling revealed that SHS exposure had a significant direct effect on DSH (β’ = 0.7458, p  < 0 0.001). In contrast, air pollution days demonstrated both a direct effect (β’ = 0.3323, p  < 0.001) and an indirect effect on DSH through a mediating pathway (β’ = 0.054, p  < 0.001). Conclusion Using nationally representative data from 20 cities in China, this study provides compelling evidence of the detrimental impact of environmental air pollution on DSH. It underscores the urgent need for stronger environmental protection policies and the development of effective mental health strategies to reduce DSH and alleviate environmental strain on mental health.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Adolescent / Adult / Air Pollutants - adverse effects / Air pollution / Air Pollution - adverse effects / Air Pollution - statistics & numerical data / Air quality indexes / Analysis / Biostatistics / China - epidemiology / Cities / Cities - epidemiology / College students / Data collection / Deliberate self-harm / Environmental aspects / Environmental Exposure - adverse effects / Environmental Health / Environmental impact / Environmental protection / Environmental protection policy / Epidemiology / Exposure / Female / Health aspects / Humans / Male / Medicine / Medicine & Public Health / Mental disorders / Mental health / Mixed air pollution / Nitrogen dioxide / Passive smoking / Per capita / Pollutants / Pollution index / Prevention / Psychological aspects / Public Health / Questionnaires / Regression analysis / Regression models / Risk factors / Secondhand smoke / Self destructive behavior / Self-Injurious Behavior - epidemiology / Self-injury / Smoking / Social aspects / Socioeconomic factors / Socioeconomic status / Socioeconomics / Students / Students - psychology / Students - statistics & numerical data / Suicides & suicide attempts / Surveys / Surveys and Questionnaires / Tobacco smoke / Tobacco Smoke Pollution - adverse effects / Universities / University students / Vaccine / Variables / Young Adult / Young adults