Figure 1

Der 1 allergen levels (a) on tape samples from futon or mattress covers, (b) in Petri dish samples from the bedroom floor, and (c) in Petri dish samples from the bedroom 100 cm above the floor, for patients in the intervention group before intervention (in 2009) and 1 year later (after intervention), and in the non-intervention group during the same test periods. Mean values were compared by using the Wilcoxon matched-pairs T-test. A P value of <0.05 was considered statistically significant. † P < 0.01; NS: not significant.