Air quality in urban parking garages (PM10, major and trace elements, PAHs): Instrumental measurements vs. active moss biomonitoring

•In garages, average PM10 level was about 110 μg m−3, exceeded the EU set value.•Zn, Ba and Cu were two orders of magnitude higher than those at urban sites in Europe.•Average B[a]P concentrations was 1.5 ng m−3 exceeded the EU set value -1 ng m−3.•Heavy metals, in comparison with PAHs, are dominant contributors to the cancer risk.•Moss bags application for indoor air quality assessment needs further evaluation.

This study was performed in four parking garages in downtown of Belgrade with the aim to provide multi-pollutant assessment. Concentrations of 16 US EPA priority PAHs and Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr and Zn were determined in PM10 samples. The carcinogenic health risk of employees' occupational exposure to heavy metals (Cd, Cr, Ni and Pb) and PAHs (B[a]A, Cry, B[b]F, B[k]F, B[a]P and DB[ah]A) was estimated. A possibility of using Sphagnum girgensohnii moss bags for monitoring of trace element air pollution in semi-enclosed spaces was evaluated as well. The results showed that concentrations of PM10, Cd, Ni and B[a]P exceeded the EU Directive target values. Concentration of Zn, Ba and Cu were two orders of magnitude higher than those measured at different urban sites in European cities. Cumulative cancer risk obtained for heavy metals and PAHs was 4.51 × 10−5 and 3.75 × 10−5 in M and PP, respectively; upper limit of the acceptable US EPA range is 10−4. In the moss, higher post-exposure than pre-exposure (background) element concentrations was observed. In comparison with instrumental monitoring data, similar order of abundances of the most elements in PM10 and moss samples was found. However, using of the S. girgensohnii moss bag technique in indoor environments needs further justification.