Cyclic and linear siloxanes in indoor air from several northern cities in Vietnam: Levels, spatial distribution and human exposure

- Siloxanes were found widely in indoor air from Northern in Vietnam.
- Mean concentration of cyclic and linear siloxanes was 228 and 469 ng m−3, respectively.
- The highest siloxanes concentrations were measured at hair salons.
- The significant correlation existed between D4, D5, and D6 in indoor air.
- Mean exposure dose to siloxanes through inhalation by infants was 1020 ng kg-bw−1 d−1.

Earlier studies have reported the occurrence of cyclic and linear siloxanes in personal care and household products. Nevertheless, there is a lack of information on the occurrence of siloxanes in indoor air. In this study, four cyclic and six linear siloxanes were measured in 97 indoor air samples collected from various micro-environments in four cities in northern, Vietnam, during September 2016 to January 2017. The total concentrations of siloxanes (TSi) in particulate and gas phases ranged from 141 to 7220 μg g−1 (mean: 1880) and 23.8-1580 ng m−3 (mean: 321), respectively. The total concentrations of cyclic siloxanes (TCSi), linear siloxanes (TLSi), and TSi in indoor air were 1.91-1500 ng m−3, 21.8-817 ng m−3, and 41.8-1950 ng m−3, respectively. The highest mean concentration of siloxanes was found in indoor air from hair salons in Hanoi. The concentrations of siloxanes in air collected from homes in Hanoi were higher than those from other smaller cities such as Bacninh, Thaibinh, and Tuyenquang. The human exposures to siloxanes through inhalation were estimated for various age groups based on the measured concentrations. The mean inhalation exposure doses to total siloxanes for infants, toddlers, children, teenagers, and adults were 352, 219, 188, 132, and 95.9 ng kg-bw−1 d−1, respectively.

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