Oxidative potential and chemical composition of PM2.5 in office buildings across Europe – The OFFICAIR study

Tamás Szigeti,Christina Dunster,Andrea Cattaneo,Domenico Cavallo,Andrea Spinazzè,Dikaia E Saraga,Ioannis A Sakellaris,Yvonne De Kluizenaar,Eric J.M Cornelissen,Otto Hänninen,Matti Peltonen,Giulia Calzolai,Franco Lucarelli,Corinne Mandin,John G Bartzis,Gyula Záray,Frank J Kelly

doi:10.1016/j.envint.2016.04.015

Abstract

In the frame of the OFFICAIR project, indoor and outdoor PM2.5 samples were collected in office buildings across Europe in two sampling campaigns (summer and winter). The ability of the particles to deplete physiologically relevant antioxidants (ascorbic acid (AA), reduced glutathione (GSH)) in a synthetic respiratory tract lining fluid, i.e., oxidative potential (OP), was assessed. Furthermore, the link between particulate OP and the concentration of the PM constituents was investigated.The mean indoor PM2.5 mass concentration values were substantially lower than the related outdoor values with a mean indoor/outdoor PM2.5 mass concentration ratio of 0.62 and 0.61 for the summer and winter campaigns respectively. The OP of PM2.5 varied markedly across Europe with the highest outdoor OPAA m−3 and OPGSH m−3 (% antioxidant depletion/m3 air) values obtained for Hungary, while PM2.5 collected in Finland exhibited the lowest values. Seasonal variation could be observed for both indoor and outdoor OPAA m−3 and OPGSH m−3 with higher mean values during winter. The indoor/outdoor OPAA m−3 and OPGSH m−3 ratios were less than one with 4 and 17 exceptions out of the 40 cases respectively. These results indicate that indoor air is generally less oxidatively challenging than outdoors. Correlation analysis revealed that trace elements play an important role in determining OP, in particular, the Cu content. Indoor air chemistry might affect OP since weaker correlations were obtained for indoor PM2.5. Our findings also suggest that office workers may be exposed to health relevant PM constituents to a different extent within the same building.

Highlights

Numerous epidemiological and toxicological studies have shown a relationship between ambient particulate matter (PM) exposure and adverse health effects in humans (Brook et al, 2010; Hoek et al, 2002; Laden et al, 2000; Schwartz et al, 2002)
Considerable spatial and temporal differences in the outdoor PM2.5 mass concentration values could be observed among the study areas and seasons
The highest seasonal variation for outdoor PM2.5 mass concentration was observed in Hungary where the highest contrast was recorded between the ambient temperature values during the summer and the winter campaigns

Summary

Introduction

Numerous epidemiological and toxicological studies have shown a relationship between ambient particulate matter (PM) exposure and adverse health effects in humans (Brook et al, 2010; Hoek et al, 2002; Laden et al, 2000; Schwartz et al, 2002). Different pathophysiological mechanisms have been proposed to explain PMs contribution to respiratory and cardiovascular diseases; there are still remaining questions to be answered. The pulmonary epithelial cells are protected against undue oxidation by the respiratory tract lining fluid (RTLF) which contains low-molecular weight antioxidants (i.e., reduced glutathione, ascorbate, urate) and antioxidant enzymes. Either the increased exposure to oxidants or the presence of decreased antioxidant defenses could lead to oxidative stress which in turn can activate a number of redox sensitive signaling pathways (Anseth et al, 2005; Kelly, 2003; Kelly and Fussell, 2012). The identification of the oxidatively active components of PM is still a challenging task since particles vary in size, mass, number, shape, aggregation status, surface area as well as chemical composition

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