The results of field studies using passive sampling tubes according to Palmes for the determination of NO2 are described. Investigations were made at roads with heavy traffic in Berlin. The immission (ambient) concentrations measured were compared with the results of automatic monitors used by the Berliner Luftgutemessnetz (BLUME). Compared with the measurement results of the automatic monitors, in most cases there were no remarkable deviations, except for some measurement sites. Regarding the results of all measurements carried out, the passive Palmes samplers are suitable for screening measurements of ambient NO2 concentrations, e.g. with regard to 40 (2) BIm-SchG. However, they cannot substitute automatic monitor measurements. In practical use, the special outdoor conditions have to be taken into consideration, especially the different flow conditions varying with the kind of installation of the samplers and the choice of the measurement sites.