Associations of gestational and the first year of life exposure to ambient air pollution with childhood eczema in Hubei, China Abstract Whether exposure to air pollution is associated with the increased incidence of childhood eczema is controversial. Only a few previous researches about the relationship between gestational and early-life exposures to ambient air pollutants and childhood eczema were conducted in China, and there is a lack of studies in Hubei province. This study aimed to explore the associations between air pollution exposure in gestation and the first year of life and childhood eczema. From November to December 2017, a total of 3383 children aged 3–6 years were recruited from 12 kindergartens in Hubei, China; 3167 were included in the final analysis. Parent-reported data involved with childhood eczema was inquired by questionnaire, and the concentrations of NO2, PM2.5, and PM10 were acquired from air quality monitoring stations which were the nearest to the twelve kindergartens. A binary logistic regression model was used to evaluate the associations of period-mean concentrations of individual pollutant exposure with childhood eczema. Of the 3167 children, 848 (26.8%) had a history of doctor-diagnosed eczema. After adjusting for the covariates, high levels of NO2, PM2.5, and PM10 exposures were significantly associated with a positive increase in risk of childhood eczema during the gestational period and the first year of life. In the gestational period, the estimate OR in the 3rd and 4th quartiles of NO2 was 1.256 and 1.496, respectively. During the first year of life, the estimate OR in the 3rd and 4th quartiles of NO2was 1.371 and 1.335, respectively. Our study indicated that the gestational period and the first year of life exposures to high levels of ambient NO2, PM2.5, and PM10 were significantly associated with increased eczema among preschool children. Some effective measures of prevention and intervention could be developed for preschool children.