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Perfluoroalkyl contaminants in window film: indoor/outdoor, urban/rural, and winter/summer contamination and assessment of carpet as a possible source.

Window film concentrations of ionic perfluoroalkyl contaminants (PFCs) were determined indoors and outdoors at urban, suburban, and rural sites in or near Toronto, Ontario, Canada, to identify locations of relatively elevated concentrations and the nature of potential sources. The role of carpet installation and floor wax application as possible sources was also evaluated by sampling indoor window films at five sites before and after new carpet installations, at one site before and after a floor wax application, and at two carpet stores. Low concentrations were found in all outdoor window films, with comparable relative proportions of individual PFCs among sites, suggesting similar sources to the outdoor environment and rapid air mixing. PFCs in indoor window film were up to 20-fold greater than outdoor, providing some evidence that a significant proportion of PFCs originate from the indoor environment, although precipitation wash-off of outdoor window film may be confounding these results. For both indoor and outdoor film, PFC concentrations generally changed between the summer and winter but the chemical profiles were similar between seasons. Concentrations of PFCs in window films increased one month post carpet installation at three of the five sites, suggesting that some of the carpets may have been a source to the indoor environment. Indoor window films from two carpet stores (sigmaPFC = 16 and 7 pg/cm2) contained higher concentrations than the other indoor locations (sigmaPFC = < MDL to 4.3 pg/cm2), which may reflect the carpets stored within these buildings. The use of window film allowed collection of a wide range of samples and the results can be used to focus the efforts of more traditional air sampling campaigns.