Characteristics and airborne chemical concentration in the control and BTX-exposed groups.

Abbreviations: IQR, interquartile range; SD, standard deviation.*PP values were obtained from Pearson's chi-square test for categorical variables and ANOVA for continuous variables.Because all controls have values less than LOD for benzene, toluene, and xylene of 0.01, 0.3, 0.3 mg/m3 respectively, these data were assigned a value corresponding to one half of the LOD in the analysis (i.e. 0.005 mg/m3 for benzene).Categorical variables are expressed as n (%), and continuous variables are expressed as mean ± SD.Characteristics and airborne chemical concentration in the control and BTX-exposed groups.