Comparison of the mass concentration of size-resolved particulate matter inside a selected fire station in Poland and in the atmospheric air in its immediate surroundings

The objective of this study was to evaluate the mass concentration of size-resolved (PM 1 , PM 2.5 , PM 4 , PM 10 , PM 100 ) particulate matter (PM) in the indoor air of a selected fire station in Poland and to compare them with the concentrations of the same PM fractions in the atmospheric air. Optical measurements of PM concentrations were conducted for 12 hours a day, simultaneously inside and outside of the fire station, for 14 days in heating and non-heating seasons. In both measurement seasons, the average PM concentrations were higher in the fire station (26–44 µg/m 3 ) than in the ambient air (9–32 µg/m 3 ). The proportion of fine particles in the total PM mass was found to be higher in the fire station (83–90%) than in the atmospheric air (40–78%). The findings of conducted analyses substantiate the notion that the concentrations and mass size distribution of PM in the fire station deviates from the concentrations and mass distribution for the urban background, a phenomenon that is attributable to the unique characteristics of the fire station and the prevalence of internal sources within it.