The location of municipal solid waste (MSW) landfills in inappropriate places is a serious risk to the quality of all environmental factors. These waste disposal sites can become major sources of air quality deterioration through emissions of toxic gas resulted from anaerobic decomposition of organic waste. The paper discusses in detail the qualitative and quantitative effects of municipal waste landfills of the main urban settlements in Suceava County (Suceava City municipal landfill and Gura Humorului, Rădăuţi, Siret, Câmpulung Moldovenesc, Fălticeni and Vatra Dornei urban waste landfills) on air quality. The dispersion of methane emitted from the largest MSW landfill in the county, the Suceava municipal landfill respectively, is also presented, taking into account seasonal, daytime and nighttime meteorological parameters.