The method of potential ecological effects assessment understood as decreasing of atmospheric air pollution that results from usage of straw biomass as the alternative fuel to coal was presented in the paper. Ecological effects expressed by the amount of carbon dioxide not emitted into the air and also the level (quantity) of decrease in nitric oxide and sulphur dioxide emission were calculated. The research had spatial character and covered Poland’s area in terms of provinces. Central Statistical Office of Poland (in Polish: GUS) source materials accounted for research base and the surveys presented in the paper were of methodical character. The authors presented their own scheme (algorithm) illustrating particular stages of the proposed method. In the application part, their results were validated. Presented in the paper assessment of ecological effects of gaining straw biomass energy revealed that potential significant decrease of sulphur oxides and sulphur dioxide emission into the air will take place in Poland. Moreover, carbon dioxide will not be emitted. The suggested method constitutes the first stage of surveys performed in that research range. Evaluation of potential demand for appliances to burn straw biomass as well as presentation of economical effects of replacing coal with this medium of energy will be the next stage of work.