[en] A three-year programme was carried out in which the methods most frequently used for environmental monitoring were compared. These methods were: thermoluminescence, high-pressure ionization chamber, laboratory spectrometry of samples and in situ spectrometry. The details of applied methodology and organization of measurements performed in rural and urban areas are described. Source results are extensively presented in a series of tables. Integrating dosimeters and repeated/within a yearly period/ momentary measurements with e.g. ionization chamber, yield results best representing long-term averages. The advantage of the ionization chamber method is that several measurements can be rapidly performed over large areas. However, such measurements should not be made in the winter or summer, as differences between momentary values and long-term averages are most pronounced during those two periods of the year. The disadvantages of the method of laboratory spectrometry of samples are the difficulties in obtaining samples, need to use sophisticated equipment and data management systems, and the divergence between final results and long-term averages, due to the fact that one cannot include the influence of natural humidity or snow cover in such measurements. In situ spectrometry is hindered by the weight and sophistication of portable spectrometric systems, long measurement periods and the complexity of data management shared with the other spectrometric technique. (author)