Personal exposures and indoor, residential outdoor, and urban background levels of fine particle trace elements in the general population

Abstract

Personal exposures and indoor, residential outdoor, and urban background levels of PM_2.5 and PM₁ were measured simultaneously in Göteborg, Sweden. A total of 270 24 hour samples from 30 subjects were analyzed for elemental concentrations using X-ray fluorescence (XRF) spectroscopy. Personal exposures to PM_2.5 were significantly higher for Cl, Ca, Ti, and Fe compared with the other locations. For most elements, residential outdoor levels were significantly higher than urban background levels. Correlations between personal exposure and stationary measurements were moderate to high for Zn, Br, and Pb (r_s = 0.47–0.81), while Ca and Cu showed low correlations. The penetration indoors from outdoors was 0.7, as calculated from S and Pb ratios. For the pairs of parallel PM₁ and PM_2.5 measurements, only Ca and Fe levels were significantly lower for PM₁ at all sites. Significant correlations were found between urban background mass concentrations and personal exposure levels for elements attributed to combustion processes (S, V, and Pb) and resuspended dust (Ti, Fe, and Zn), indicating that both sources could be relevant to health effects related to urban background mass. Air mass origin strongly affected the measured urban background concentrations of some elements (S, Cl, V, Ni, Br, and Pb). These findings were also seen for personal exposure (S, Cl, V, and Pb) and indoor levels (S, Cl, V, Ni, and Pb). No differences were seen for crustal elements. Air mass origin should be taken into account in the description and interpretation of time series studies of air pollution and health.