LAUSR

Background Ambient nitrogen dioxide (NO 2 ) is a common air pollutant in developing countries and causes skin conditions, but its effect on eczema in subtropical areas is not clear in China. Object To measure the effect of short-term exposure of NO 2 on the incidence of eczema and the change of outpatient visits. Methods Data of daily temperature, air pollutants, and outpatient visits from 2013 to 2018 were collected in a row. The generalized additive model (GAM) and Poisson distribution were used to assess the association between short-term exposure of NO 2 and the outpatient visits of patients with eczema. The cumulative exposure effect of lag 0–3 days and the displacement effect of NO 2 and other pollutants were considered as well. A single pollutant model was used to examine the independent association, and a two-pollutant model was adopted to control the confounding effect. Results The daily outpatient visits of eczema increased from 75.26 to 190.85 from 2013 to 2018 ( P  < 0.001). The combined influence of NO 2 and the related pollutant exerted a stronger influence on the incidence of eczema. The maximum effect of NO 2 appeared on the exposed day. (lag 0) and disappeared on day 4 (lag 3). The children and seniors were more vulnerable to NO 2 exposure. Conclusion Exposure to NO 2 is tightly associated with eczema incidence and outpatient visits. The hospitals should react to the visit fluctuations and adjust physician duty shifts to improve outpatient service efficiency.