Submicron particle-bound polycyclic aromatic hydrocarbons in the Polish teaching rooms: Concentrations, origin and health hazard

The goal of the work was to investigate the concentrations of the 16 US EPA priority polycyclic aromatic hydrocarbons (PAH) bound to submicrometer particles (particulate matter, PM₁) suspended in the air of university teaching rooms and in the atmospheric air outside. Two teaching rooms were selected in two Polish cities, Gliwice, southern Poland, and Warsaw, central Poland, differing with regard to the ambient concentrations and major sources of PM and PAH. The variabilities of indoor and outdoor 24-hr concentrations of PM₁-bound PAH, the ratio (I/O) of the indoor to outdoor 24-hr concentrations of PM₁-bound PAH, probable sources of PAH and the level of the hazard from the mixture of the 16 PAH (ΣPAH) to humans at both sites were analyzed. In both Warsaw and Gliwice, the mean concentrations of PM₁-bound ΣPAH were slightly higher in the atmospheric air than in the rooms. The indoor and outdoor concentrations of individual PAH in Gliwice were correlated, in Warsaw – they were not. Most probably, the lack of the correlations in Warsaw was due to the existence of an unidentified indoor source of gaseous PAH enriching PM₁ in phenanthrene, fluorene, and pyrene. Although the ambient concentrations of PM₁-bound PAH were low compared to the ones observed earlier at both sites, they were much higher than in other urbanized European areas. However, because of low mass share of heavy PAH in ΣPAH, the various indicators of the health hazard from the 16 PAH mixture were low compared to other regions.