Aim of the study:
The aim of the study was to assess the spatio-temporal variation in air quality in Pieniński National Park (PPN) and its buffer zone.

Material and methods:
An indicator method involving passive sampling was used. This is a Japanese method for determining concentrations, proposed by Amaya-Sugiura and modified by Krochmal and Górski. Air quality assessment was based on the ambient air concentration of nitrogen dioxide (NO2), an air pollution indicator gas.

Results and conclusions:
The highest concentration exceeding the monthly average of 35 µg·m-3 was noted in Krościenko nad Dunajcem in practically all seasons. This supports earlier results of research conducted in this area by Kozak, Miczyński and Jurkiewicz. In recent years the NO2 concentration in the centre of Krościenko in the month of November has increased from about 26-28 µg·m-3 in 2001-2004 to over 40 µg·m-3 in 2016-2018. Similarly, in the outskirts of Krościenko, where the PPN headquarters is located, it increased from 13-17 µg·m-3 to 20-30 µg·m-3. An upward trend is also perceptible in Szczawnica and at major transport hubs. This is mainly linked to the rapid growth of the motor vehicle industry and tourist expansion in the region. Concentrations in the area of the Trzy Korony summit and other sites in the higher parts of the Pieniny Mountains are similar and do not exceed 10 µg·m-3 at any time during the analytical period.