Evaluation of performance reference compounds in polyethylene-based passive air samplers Michael E. Bartkow a, * , Kevin C. Jones b , Karen E. Kennedy a , Neil Holling c , Darryl W. Hawker d , Jochen F. Mu ¨ller a a National Research Centre for Environmental Toxicology (ENTOX), University of Queensland, Coopers Plains, Queensland 4108, Australia b Department of Environmental Sciences, Lancaster University, Lancaster LA14YQ, UK c Queensland Health and Scientific Services, Queensland Health, Coopers Plains, Queensland 4108, Australia d Faculty of Environmental Sciences, Griffith University, Nathan, Queensland 4111, Australia Received 22 September 2005; accepted 20 December 2005 Performance reference compounds (or depuration compounds) can be used to correct the influence of wind speed on sampler performance. Abstract Polyethylene-based passive air samplers (PSDs) were loaded with performance reference compounds (PRCs) and deployed in a wind tunnel to examine the effects of wind speed on sampler performance. PRCs could be loaded reproducibly into PSDs, with coefficients of variation only exceeding 20% for the more volatile compounds. When PSDs were exposed to low (0.5e1.5 m s ÿ1 ) and high (3.5e4.5 m s ÿ1 ) wind speeds, PRC loss rate constants generally increased with increasing wind speed and decreased with increasing sampler/air partition coefficients. PSD-based air concentrations calculated using PRC loss rate constants and sampler/air partition coefficients and air concentrations measured using active samplers compared closely. PRCs can be used to account for the effect of differences in wind speeds on sampler performance and measure air concentrations with reasonable accuracy. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Passive air sampler; Performance reference compound; PRCs; Wind effects; Polyaromatic hydrocarbons; Polychlorinated biphenyls 1. Introduction 1.1. Background A range of passive air samplers for semi-volatile organic compounds (SOCs) such as semi-permeable membrane devices (SPMDs), polyurethane foam (PUF) samplers, XAD- based samplers and polyethylene-based sampling devices (PSDs) are currently in use (Bartkow et al., 2004a; Jaward et al., 2004; Shen et al., 2005; Soderstrom et al., 2005). Recent work has shown that PSDs are an accessible and affordable passive sampler that can be used in various surface area to vol- ume ratios, depending on monitoring requirements (Bartkow et al., 2004a). For many chemicals, performance of passive air samplers is influenced by changes in wind speed (Harner et al., 2003; Soderstrom and Bergqvist, 2004). In this case, the rate of chem- ical exchange between the sampler and atmosphere is domi- nated by the thickness of the air-side boundary layer. An increase in wind speed can then reduce the thickness of the boundary layer, resulting in higher rates of exchange across the boundary layer. If samplers are exposed to different wind speeds at different sites then comparisons between sites can become confounded, unless the effect of wind is taken into consideration. Huckins et al. (2002a) showed that the loss of performance reference compounds (PRCs) loaded into passive water * Corresponding author. Tel.: þ61 7 3274 9147; fax: þ61 7 3274 9003. E-mail address: m.bartkow@uq.edu.au (M.E. Bartkow). 0269-7491/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2005.12.043