Particle size-dependent and route-specific exposure to liquid crystal monomers in indoor air: Implications for human health risk estimations

Huiju Lin; Xinxing Li; Xian Qin; Yaru Cao; Yuefei Ruan; Michael K H Leung; Kenneth M Y Leung; Paul K S Lam; Yuhe He

doi:10.1016/j.scitotenv.2023.168328

Particle size-dependent and route-specific exposure to liquid crystal monomers in indoor air: Implications for human health risk estimations

Sci Total Environ. 2024 Jan 15:908:168328. doi: 10.1016/j.scitotenv.2023.168328. Epub 2023 Nov 4.

Authors

Huiju Lin¹, Xinxing Li², Xian Qin³, Yaru Cao³, Yuefei Ruan⁴, Michael K H Leung², Kenneth M Y Leung⁴, Paul K S Lam⁵, Yuhe He⁶

Affiliations

¹ School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
² School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
³ State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong, China.
⁴ Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China; State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong, China.
⁵ Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China; State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong, China; Department of Science, School of Science and Technology, Hong Kong Metropolitan University, Hong Kong, China.
⁶ School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China. Electronic address: henry.he@cityu.edu.hk.

PMID: 37926258
DOI: 10.1016/j.scitotenv.2023.168328

Abstract

In indoor environments, liquid crystal monomers (LCMs) released from display devices is a significant concern, necessitating a comprehensive investigation into their distribution behaviors and potential health risks. Herein, we examined various LCMs in educational and workplace air and compared their associated health risks through inhalation and dermal absorption routes. 4-propyl-4'-vinylbicyclohexyl (3VbcH) and 4,4'-bis(4-propylcyclohexyl) biphenyl (b3CHB) with median concentrations of 101 and 1460 pg m^-3, were the predominant LCMs in gaseous and particulate phases, respectively. Composition and concentration of LCMs differed substantially between sampling locations due to the discrepancy in the quantity, types, and brands of electronic devices in each location. Three models were further employed to estimate the gas-particle partitioning of LCMs and compared with the measured data. The results indicated that the HB model exhibited the best overall performance, while the LMY model provided a good fit for LCMs with higher log K_oa (>12.48). Monte Carlo simulation was used to estimate and compared the probabilistic daily exposure dose and potential health risks. Inhalation exposure of LCMs was significantly greater than the dermal absorption by approximately 1-2 orders of magnitude, implying that it was the primary exposure route of human exposure to airborne LCMs. However, certain LCMs exhibited comparable or higher exposure levels via the dermal absorption route due to the significant overall permeability coefficient. Furthermore, the particle size was discovered to impact the daily exposure dose, contingent on the particle mass-transfer coefficients and accumulation of LCMs on diverse particle sizes. Although the probabilistic non-carcinogenic risks of LCMs were relatively low, their chronic effects on human beings merit further investigations. Overall, this study provides insights into the contamination and potential health risks of LCMs in indoor environments, underscoring the importance of considering particle sizes and all possible exposure pathways in estimating human health risks caused by airborne organic contaminants.

Keywords: Dermal exposure; Gas−particle partitioning; Indoor environment; Monte Carlo simulation; Non-carcinogenic health risks.

MeSH terms

Air Pollutants* / analysis
Air Pollution, Indoor* / analysis
Dust / analysis
Humans
Liquid Crystals*
Particle Size

Substances

Air Pollutants
Dust