The article assesses to what extent reduced the impact on air quality of a complex of detached coal-fired houses as a result of some thermal renovation works which lowered the fuel consumption and reduced emissions of pollutants into the air. The assessment was done on the basis of results of dispersion modelling for selected substances (SO2, NO2, CO, PM10, B(a)P and PCDD/F) in the ambient air with the use of CALMET/CALPUFF models. The calculation process encompassed preparation of the data on spatial features of the area, making a three-dimensional grid of meteorological data, definition of geometrical parameters of substitute emitters and making calculations of distribution of pollutant concentrations for adopted emission variants. The obtained calculation results point to the possibility of exceedance of the permissible concentrations in the air of SO2, PM10 and B(a)P in case of emission of these substances from 60 residential buildings of the type situated close to each other and characterized by low thermal insulating power. It is possible to considerably reduce this impact by conducting a number of works increasing the energy efficiency of these buildings (replacement of windows, insulation of external walls, flat roof insulation and replacement of the heating system). The suggested measures will allow to reduce the concentrations of the aforementioned substances in the air resulting from emissions from these buildings, to the level definitely below the permissible level, with the exception of B(a)P, in case of which compliance with the permissible annual average concentrations in the air requires additionally to change the type of used fuel.

English title: Assessment of the effects of thermal renovation of detached houses. 2. Reduction the impact on the ambient air quality.