The present work has the purpose to make a comparative evaluation of the different types detector tubes--for analysis, long-term and passive for determination of NO2 and the results to be compared, with those received by the spectrophotometric method and the reagent of Zaltsman. Studies were performed in the hall of the garage for repair of diesel buses during one working shift. The results point out that the analysing tubes for NO2 give good results with the spectrophotometric method. The measured average-shift concentrations of NO2 by long-term and passive tubes are juxtaposed with the average-received values with the analytical tubes and with the analytical method.