The composition of 19 elements - Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ba, Pb - were compared in the peripheral (younger) and central (older) parts of the upper surface of the epiphytic lichen Xanthoria parietina thallus from the bark of Sorbus aucuparia in Moscow city using sample-nondestructive μ-XRF spectrometer. This species is often used in biomonitoring of air quality. The results showed that the elements content was highly variable. Mean values of atomic percent of Fe, Co, Zn, and Pb were statistically higher in the central part of the upper surface, while P, S, Cl, K, Ca, and Mn were higher in the peripheral part. Differences between other elements were not statistically valid, but there is a trend to greater maintenance of the majority of the elements on the surface of the central part of the thallus. Mapping the distribution of some elements on the part of the thallus surface is presented.