OBJECTIVES: As the largest organ of the human body, the skin is the major exposure route of NO 2 . However, the evidence for a relationship between NO 2 exposure and dermatologic diseases (DMs) is limited . This time-series study was conducted to assess the short-term effect of nitrogen dioxide (NO 2) exposure on DMs outpatient visits in Xinxiang, China .

METHODS: Daily recordings of NO 2 concentrations, meteorological data, and the outpatient visits data for DMs were collected in Xinxiang from January 1st , 2015, to December 31st , 2018 . The analysis method used was based on the generalized additive model (GAM) with quasi-Poisson regression to investigate the relationship between NO 2 exposure and DMs outpatient visits . Several covariates, such as long-term trends, seasonality, and weather conditions were controlled .

RESULTS: A total of 164,270 DMs outpatients were recorded . A 10 μg/m 3 increase in NO 2 concentrations during the period was associated with a 1.86% increase in DMs outpatient visits (95% confidence intervals [Cl]: 1.06-2.66 %). The effect was stronger (around 6 times) in the cool seasons than in warmer seasons and younger patients (< 15 years of age) appeared to be more vulnerable .

CONCLUSIONS: The findings of this study indicate that short-term exposure to NO 2 increases the risk of DMs in Xinxiang, China, especially in the cool seasons . Policymakers should implement more stringent air quality standards to improve air quality.