Relationship between ambient ozone concentrations and daily hospital admissions for childhood asthma/atopic dermatitis in two cities of Korea during 2004-2005

The objective of this study was to estimate the association between ambient ozone levels and hospitalization for asthma/atopic dermatitis among children younger than 15 years old living in Seoul and Ulsan, Korea, in the years 2004-2005. Estimated relative risks of hospital admissions associated with an interquartile range (IQR) increase in ozone concentration were calculated using a generalized additive Poisson model. For childhood asthma, the effect of an ozone increase on the relative risks in Ulsan [1.21 (95% CI, 1.10-1.34)] was higher than that in Seoul [1.05 (95% CI, 0.99-1.11)]. The relative risks for childhood atopic dermatitis were also found to be higher in Ulsan [1.38 (95% CI, 0.80-2.36)] than in Seoul [1.28 (95% CI, 1.04-1.58)]. These results support previously reported findings and also indicate that ozone concentrations at levels below the standards in the Republic of Korea can be correlated with asthma hospital admissions in children.