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

Abstract

The general population is exposed to particulate air pollution from many different local and regional sources. Examples of local sources are traffic, biomass burning and resuspended dust, while regional sources are dominated by combustion processes from heating, traffic and industries. The overall aim of this thesis was to characterise the personal exposure to trace elements in fine particles, mainly PM 2.5 and investigate how the exposure is related to indoor and outdoor levels. Particulate matter was collected on filters and analysed for elemental content by X-ray fluorescence (XRF) spectroscopy.In the general population in Göteborg, personal exposures to Cl, Ca, Ti and Fe were significantly higher compared with indoor, residential outdoor and urban background levels. Significant correlations were also found between urban background PM mass and personal exposure to elements related to both combustion (S, V and Pb) and resuspended dust (Ti, Fe and Zn), indicating that both sources could be relevant for health effects from urban background PM. In a community where wood burning for domestic heating is common, significantly (66-80%) higher personal exposures and indoor levels were found for K, Ca and Zn compared with a reference group living in the same area, indicating that these elements could be good markers for wood smoke. In a study in Stockholm concerning children's environments (home, school and preschool), higher indoor than outdoor levels of Ti were found, while long-range-transported (LRT) elements (S, Ni, Br and Pb) were higher outdoors. A community located 25 km from the city centre had significantly lower outdoor levels of crustal and traffic-related elements compared with both the city centre and a suburban area. The levels of Fe and Cu were four times higher in the central communities. Outdoors, Cu levels were found to correlate well with the traffic marker NO 2 , making it a possible elemental marker for traffic-related aerosols in health studies. Roadside measurements of fine and ultrafine (<100 nm) particles were performed along a major approach road to Göteborg and the levels of ultrafine particles were influenced not only by traffic intensity, but also, by wind speed and direction, as well as boundary layer height. No correlation was found between PM 2.5 and ultrafine particles or traffic, but there was a correlation between PM 2.5 and particles sized 100-368 nm. In all environments studied, the origin of LRT air masses had a strong effect on exposure and levels of PM elements.In conclusion, this thesis demonstrates that elemental analysis is a useful method for better characterising human exposure to fine particles. For several elements, the personal exposure is often higher than corresponding indoor levels. The origin of LRT elements affected not only outdoor levels, but also, the personal exposure and indoor levels, and should be taken into account in time series studies of air pollution and health.

Exposure to fine particles (PM2.5 and PM1) and black smoke in the general population: personal, indoor, and outdoor levels

“…In an extension of the present study, the particle mass was analyzed for trace elements. Differences between air masses regarding elemental composition were large enough to be significant even for personal exposure to and indoor levels of elements of outdoor origin, such as sulfur, vanadium, lead, and chlorine (Molna´r et al, 2006). In our study, five out of 42 measurements of urban background levels of PM 2.5 were above 25 mg/m 3 , the recommended air quality guideline from WHO (99th percentile, 3 days/year).…”

Source Apportionment of PM2.5 Using Positive Matrix Factorization (PMF) and PMF with Factor Selection

“…The data on the elemental concentrations can be found in Molnár et al (2006). The chemically undetermined part of PM 2.5 , PM rest , accounted for, on average, 59% of the total PM 2.5 .…”

“…was provided by the Environmental Agency in Gothenburg. More detailed information regarding the study design, the participants, and the sampling can be found in Molnár et al (2006) and Johannesson et al (2007). The study was approved by the Ethics Committee at the University of Gothenburg.…”

“…An energy-dispersive X-ray fluorescence (EDXRF) spectrometer at the Department of Chemistry, Atmospheric Science, University of Gothenburg, was used to analyze the elemental composition of all filter samples (Molnár et al, 2006). The EDXRF spectra were processed and quantified using the Quantitative X-ray Analysis System (QXAS) and the Analysis of X-ray spectra by Iterative Least-square fitting (AXIL) (Bernasconi et al, 2000).…”

“…: +46-31-786 2857; Fax: +46-31-82 50 04 E-mail address: peter.molnar@amm.gu.se exposure (Oglesby et al, 2000;Sarnat et al, 2005;Sorensen et al, 2005;Johannesson et al, 2007). Some studies have also characterized the chemical composition of the PM 2.5 in personal exposures (Yakovleva et al, 1999;Oglesby et al, 2000;Kinney et al, 2002;Lai et al, 2004;Larson et al, 2004;Janssen et al, 2005;Molnár et al, 2005;Molnár et al, 2006;Zhao et al, 2006;Johannesson et al, 2011). The infiltration of ambient air indoors can be calculated using elements with no indoor sources (e.g., S or Pb), and thus, the influence of ambient air on indoor air can be assessed (Hänninen et al, 2011).…”