Unveiling human exposure to organic contaminants during sleeping

Despite evidence on the prevalence of organic contaminants in indoor environments, limited information is available on personal exposure to chemicals while sleeping. To fill this knowledge gap, we conducted two sampling campaigns to obtain the levels of plasticizers, synthetic musks, and ultraviolet absorbents by personal and stationary passive samplers on university students during sleeping period. Gaseous, particulate, and integrated constituents were collected with disks, membrane filters and meshes, and watchbands (traditional wristbands), respectively. Active samples in selected indoor environments and bedding wipes were simultaneously collected. Fourteen plasticizers, seven synthetic musks, and six ultraviolet absorbents were identified in personal passive samplers. Plasticizers were the most abundant constituents in different sample categories (42-99 %). Concentrations of the target compounds were 0.6-74 and 1-3500 times higher in personal disks and watchbands than in stationary ones, implying source-proximity effect. The time-normalized concentrations of volatile compounds (log K_OA < 10) in personal watchbands were comparable to those during other time periods for adults in the literature. Bedding supplies acted as an important mediator of chemical transfer and human exposure to organic contaminants during sleeping. Daily dermal exposure was underestimated by 62-100 % if sampling was conducted in surrounding environment rather than adjacent to the skin. Apparently, personal sampling better represents individual dynamic exposure during sleeping period. Changing into clean pajamas and frequently washing bedding supplies help to reduce potential health hazard.