We consider methodical issues of analysis of the ecological impact of atmospheric pollution caused by petroleum gas flares in oil fields on forests using geoinformation systems and images from space. The landscape structure of oil-producing territories in Southwestern Siberia is determined based on processing of medium-resolution images obtained from Resurs-O1 satellite. Simulated data are compared with those obtained during long-term measurements of aerosol concentrations in Western Siberia performed by the Institute of Atmospheric Optics SB RAS. Relative areas of polluted landscapes are determined depending on oil production rates.