During the lichen indication investigation of air quality in the outskirts of the Yavoriv state mining-chemical factory „Sirka" in the Lviv region the mapping of the polluted territory with according to Index of Atmospheric Purity (IAP) and Improved Index of Atmospheric Purity (IAP18) was made. It was discovered 81 species of epiphytic lichens, for which the meanings of the Ecological Index (Qi) are calculated and reported for 28 widespread species. At the investigated territory 4 isotoxic lichen zones are established. Their position is determined by the main springs of pollution: „Sirka" factory and highways. These sources of pollution also influence the distribution of the indicatory species. Keywords: Ukraine; lichen indication, air pollution, indexes of air purity, lichen zones, indicators species.