abstract: The influence of freezing processes on the air properties (porosity, air capacity, air permeability) of a compacted Mollic Leptosol derived from chalk (Sielec, Pagóry Chełmskie, cultivated field) was investigated. Soil samples for the experiment were taken from the seasoned superficial soil layer of 0-10 cm. The freezing processes caused an alteration in the differential porosity of the studied soil, related to its compaction. The strongest growth of air diffusivity - causing the greatest improvement of soil pore permeability - was observed for strongly compacted soil after 3 cycles of freezing and thawing. There was no apparent correlation between the number of freezing-thawing cycles and the intensity of changes detected in the measured properties, caused by freezing.