Male motorcyclists (mean age 36 years) were recruited and randomly assigned to RRC or RRC+S. Subjects were assessed at baseline and 15 days after interventions for saccharin test, mucus contact angle, cellularity in nasal lavage and airways symptoms with the use of SNOT-20 questionnaire. Data were analyzed by two-way ANOVA for repeated measures with Bonferroni´s correction. A passive monitoring-system of nitrogen dioxide was used to assess the individual air pollution exposure along the study period. The association between nitrogen dioxide and the airways outcomes was analyzed by Spearman correlation test.