OBJECTIVE:To estimate the prevalence of respiratory symptoms and to analyze associated factors as well as peak expiratory fl ow measurements in schoolchildren.METHODS: This is a descriptive cross-sectional study with schoolchildren aged 10-14 from the city of Monte Aprazível (Southeastern Brazil). Questionnaires containing the asthma and rhinitis components of the International Study of Asthma and Allergies in Childhood were administered. The questionnaires also approached sociodemographic characteristics, predisposing factors, and family and personal medical history. Repeated measures of peak expiratory fl ow in the children, and of black carbon and particulate matter (PM 2,5 ) concentration levels were carried out. RESULTS:The prevalence of asthma and rhinitis symptoms was 11% and 33.2%, respectively. Among asthmatic children, 10.6% presented four or more wheezing attacks in the past 12 months. Past family history of bronchitis and rhinitis was associated with presence of asthma (p=0.002 and p <0.001) and rhinitis (p <0.001 and p<0.001, respectively). Regarding rhinitis, there was association with presence of mold or cracks on the house (p=0.009). Rhinitis was most frequent from June to October, a period that matches the sugarcane harvest season. Daily prevalence of peak expiratory fl ow below 20% of the median of each child's measurements was higher in days with greater PM 2,5 concentration. CONCLUSIONS:The prevalence of asthma symptoms is below and that of rhinitis is above the national average. Although within acceptable levels, pollution in the cane trash burn season may contribute to the exacerbation of asthma and rhinitis episodes.