Air pollution is one of the main environmental problem. And although average air pollution indicators in the Baltic region countries exceed limit values rarely, nevertheless, high pollution is present in some areas, damages ecosystems and public health. It is possible to use green spaces as one of the tools for cleaning atmospheric air. This article describes the scientific approaches to assess the cleansing function of urban plants. Particulate matters are considered as the main pollutant. Conclusions are drawn about the need to use an integrated approach that takes into account a number of characteristics of both plants and the ecosystems themselves, which allows solving the problems of environmental improvement in the cities of the Baltic region.