The effect of air pollution on exhaled nitric oxide of atopic and nonatopic subjects.

Levels of exhaled nitric oxide (NO) were determined in well-characterized atopic and nonatopic subjects on 4 days with a different level of outdoor air pollution. The two groups matched well regarding spirometric values, i.e., no difference with regard to FEV(1), FVC, and peak flow. On the 4 test days asymptomatic atopic subjects exhaled 1.5- to 2.4-fold higher levels of NO compared with nonatopic subjects. In both groups the increase in exhaled NO in response to air pollution was similar (2.5 times maximal increase, P < 0.01). In conclusion, atopic subjects exhale higher levels of NO compared with nonatopic subjects, but respond to a similar degree to increased levels of air pollution. Copyright 1999 Academic Press.