The aim of the present work was to look at the background levels of plutonium in air and rain samples. Two sets of Petryanov type filters through which ca. 0.5 Mm³ each of air had passed and two large samples of collected rain (170 L and 182 L) were analysed for the content of plutonium alpha-emitters. In the article the radiochemical procedure applied to these samples is described. Obtained Pu activities in air were 0.5±0.1 nBqm⁻³ and 0.7±0.1 nBqm⁻³ for²³⁸Pu and 3.1±0.2 nBqm⁻³ and 8.3±0.6 nBqm⁻³ for^239+240Pu. Activities of rain samples were 7.5±0.7 mBqm⁻³ and 14.3±0.8 mBqm⁻³ for^239±240Pu and 0.4±0.1 mBqm⁻³ and 2.1±0.2 mBqm⁻³ for²³⁸Pu, respectively, for the two samples. The most interesting finding is the largely different²³⁸Pu to^239+240Pu activity ratios (from 0.03±0.01 to 0.18±0.01) measured in the samples. This result needs conformation, but as now it suggests different origins of plutonium isotopes in incoming to Kraków air.