Background Although mounting evidence suggests that short-term exposure to ozone increases the risk of respiratory disease, cardiovascular disease and mortality, there are few studies comparing the effects of ozone in relation to urticaria in China.
Objective To evaluate the risks for urticaria exacerbations related to ambient ozone measured as 1-h maximum (O3-1 h max), maximum 8-h (O3-8 h max) and 24-h average (O3-24 h avg) concentrations.
Methods We calculated three metrics of ozone, 1-h maximum, maximum 8-h and 24-h average based on the hourly data. Generalized additive models with poisson regression incorporating natural spline functions were used to investigate short-term effects on urticaria associated with ambient ozone pollution in Lanzhou, China, using 5 years of daily data (2013-2017). We also examined the association by sex, age and season.
Results In all-year analyses, a 10 μg/m3 increase in daily average, O3-1 h max, O3-8 h max and O3-24 h avg at lag2 corresponded to an increase of 0.58%(95%CI：0.26%~0.90%), 0.82% (95%CI：0.47%~1.16%) and 2.17% (95%CI：1.17%~2.79%), respectively. The elderly populations and females were susceptible to O3, and the associations between ozone and urticaria appeared to be more evident during warm season than in the cold season.
Conclusion In conclusion, these results indicated that ozone, as a widespread pollutant, affects outpatient visits for urticaria in Lanzhou.