Indoor air quality in residential buildings in Upper Silesia, Poland

This paper presents the results of measurements of carbon dioxide (CO₂), BTESX (benzene, toluene, ethylbenzene, styrene, and xylenes), nitrogen dioxide (NO₂)_, and particulate matter with aerodynamic diameter ≤4 μm (PM₄) during the winter season in the Upper Silesia region, Poland. The samples were collected simultaneously outside and inside residential buildings (flats and houses), including kitchens, living rooms, and bedrooms. Concentrations of CO₂ were measured automatically, PM₄, gravimetrically, while BTESX and NO₂ were collected by passive methods and determined by gas chromatography (GC) and spectrophotometry, respectively. The highest CO₂ concentrations were found in bedrooms (mean value 857 ± 217 ppm), pointing to a small volume of this type of room. Toluene had the highest concentration among studied volatile organic compounds (VOCs), with the max. values 135.46 and 77.11 μg/m³ in flats and houses, respectively. Elevated concentrations of BTESX indoors (63.7 ± 39.6, 57.0 ± 32.7 and 67.7 ± 48.4 μg/m³ in bedrooms, kitchens and living rooms, respectively) point to the significant role of renovation works in flats, particularly the use of Styrofoam, as well as poor ventilation of garages located in houses. Increased NO₂ concentrations (20.5 ± 6.5, 24.9 ± 13.2 and 21.2 ± 10.9 μg/m³ in bedrooms, kitchens and living rooms, respectively) were observed with intensive use of gas cookers; however, no exceedances of the accepted levels were reported. Results indicate that occupants in studied buildings are particularly exposed to high PM₄ levels from 26.1 to 314.9 μg/m³ associated with infiltration from outdoor air, which can be dangerous for their health.