Figure 4. Bilateral and unilateral subjective patency ratings and standard errors in room air, dry air, and cold air exposure boxes.

Subjects perceived significantly less nasal congestion (greater patency), both unilaterally and bilaterally, in the cold air box and unilaterally in the dry air box, compared to the room air box (p<0.01), with the cold air box having a larger effect (p<0.01) (Wilcoxon match pairs test, with Holm–Bonferroni correction to control for multiple comparison.)