This research applied passive air pollution samplers to monitor the concentration of the pollutants nitrogen dioxide (NO2) and ozone (O3) in order to investigate the relationships between pollutant concentrations and meteorological variables. The study was carried out in three strategic sites in the municipality of Erechim, Brazil, which provide intense traffic of small and large vehicles. The pollutant analyses were performed using the method of UV/VIS spectrophotometry. NO2 concentrations varied between values below the detection limit of the passive samplers and 5.2 μg m-³, whereas the concentrations of O3 ranged from values below the detection limit of the passive samplers to 23.6 μg m-³. These values are within the O3 and NO2 concentration ranges currently allowed by Brazilian law. Low values of correlation coefficients were observed between the meteorological variables and the
concentration for both pollutants and the three sampling points. However, it was verified more evident trends for precipitation and wind speed. As the emission sources were found to be highly variable, O3 studies have to be held for longer periods in order to allow the proposition of the most appropriate forms of emission control.