Analysis of semi-volatile organic compounds in indoor dust and organic thin films by house type in South Korea

https://doi.org/10.1016/j.envres.2022.113782Get rights and content

Abstract

In this study, semi-volatile organic compounds (SVOCs) in samples of indoor dust and organic thin films obtained from 100 residential houses in South Korea, were examined, based on both target analysis using gas chromatography–mass spectrometry (GC-MS) and non-target analysis by gas chromatography–quadrupole time-of flight mass spectrometry (GC-QTOF-MS) screening. In the targeted approach, phthalates and polycyclic aromatic hydrocarbons (PAHs) were analyzed in dust and organic film samples, to find that both these classes of SVOCs were detected in dust and organic film samples, with the median concentrations of eight phthalates (Σ8 phthalate) and 16 PAHs (Σ16 PAH) being 1015.93 μg/g and 1824.97 ng/g in the dust samples, and 75.79 μg/m2 and 2252.78 ng/m2 in the organic film samples, respectively. Among the phthalates, in all house types. bis(2-ethylhexyl) phthalate (DEHP) was detected at the highest concentration, followed by dibutyl phthalate (DBP) and diisobuthyl phthalate (DiBP), with DEHP levels found to be highest in dwelling houses. DEHP levels were found to be significantly associated with building age and renovation status. Lower levels of DEHP were detected in houses less than 10 years old or that had undergone renovation in the previous 10 years. Among the assessed PAHs, a significant correlation was detected between benzo(a)pyrene in dust and building age (p < 0.05). These findings imply that the inhabitants of older houses are at a greater risk of exposure to SVOCs originating from indoor dust and organic films. Non-target screening of selected dust and organic film samples using GC-QTOF-MS data revealed the presence of numerous SVOC compounds, including triphenylphosphine oxide, (Z)-9-octadecenamide, and cyclosiloxanes, along with certain organophosphate flame retardants including tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloroisopropyl) phosphate (TDCPP), and plasticizers. These compounds identified in the non-target screening are of emerging concern, and their presence in dust and organic films needs to be estimated.

Introduction

Owing to their low volatility, semi-volatile organic compounds (SVOCs) originating from interior materials and household products within indoor environments have only recently received appreciable attention (Abbatt and Wang, 2020; Baysal et al., 2021; Morgan et al., 2022; Lucattini et al., 2018; Weschler and Nazaroff, 2017; Yang et al., 2022). Among these SVOCs, phthalates can be found in a wide range of building materials and consumer products, such as flooring, carpet padding, wall coverings, tiles, furniture, and electronics (Bornehag et al., 2005; Kweon et al., 2018). Of the phthalates identified above, the European Union risk assessments conducted in 2005 classified di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and benzyl butyl-phthalate (BBP) as hazardous substances (Kweon et al., 2018).

PAHs are common byproducts of incomplete combustion and are considered ubiquitous indoor pollutants owing to their widespread sources, which include both indoor and outdoor emissions (Blanchard et al., 2014). PAHs are also known to derive from the cooking of food (Weschler and Nazaroff, 2008; Weschler and Nazaroff, 2010), natural sources such as wildfires (Choi, 2014; Simon et al., 2016), and anthropogenic sources include the industrial burning of fossil fuels in urban areas and vehicle emissions (Fang et al., 2004; Nguyen et al., 2018). Furthermore, among the PAHs, naphthalene has long been used in South Korea as an insect repellent and wetting agent.

Fig. 1 depicts the fate and dynamics of SVOCs in indoor environments (Wu et al., 2017). Given that humans nowadays spend a considerable proportion of their daily lives within houses and other building, they are exposed to these SVOCs for extended periods of time via inhalation, ingestion, and skin contact through gases, particulates, dust, and organic thin films adsorbed on impermeable surfaces (Bi et al., 2015). Consequently, understanding the sources and behaviors of SVOCs adhered to dust and indoor surfaces is the first step in facilitating the avoidance of these compounds. Organic films have been found to develop on the building exterior of impervious surfaces such as window glass and tiles (Liu et al., 2003). Although there have been a number of previous studies that have examined SVOC emissions and dust in indoor air, only a few have focused on the emissions from organic films in the indoor environment (Butt et al., 2004; Liu et al., 2003; Wu et al., 2008), and simultaneous measurements using dust and organic film samples collected from building interiors are rarely reported.

It is also recognized that indoor SVOC emission may vary according to building type and age, renovation status, and even occupant lifestyle. Frequent use of household chemicals can also make a significant contribution to SVOC emissions. As buildings age, different SVOCs can become adsorbed to indoor surfaces and thereby accumulate over prolonged periods of time. Furthermore, due to cultural differences, Korean homes are less influenced by the outdoor environment, as their inhabitants do not wear shoes indoors, and there is little or no use of carpets in bedrooms and living rooms (Kweon et al., 2018). In addition, most houses in metropolitan areas in South Korea use liquefied petroleum or liquefied natural gas boilers for heating (Yeo et al., 2003), and thus SVOC emission within the indoor environment in South Korea may differ from that in other countries in which the combustion of coal or other fuels is used for heating. However, despite recent reports of SVOCs, such as phthalates and PAHs, found in indoor dust samples (Bornehag et al., 2005; Kweon et al., 2018), to the best of the authors’ knowledge, there have been no studies in South Korea that have systematically analyzed SVOCs with respect to housing type, building age, and renovation status. Furthermore, whereas target analysis of SVOCs based on gas chromatography–mass spectrometry (GC-MS) in conjunction with specific extraction techniques has provided quantitative information on SVOCs in the indoor environment (Cao et al., 2016; Cao et al., 2017a, b; Dubocq et al., 2021), non-target screening using gas chromatography–quadrupole time-of flight mass spectrometry (GC-QTOF-MS) can provide additional insights on the potential range of indoor SVOC compounds, but no studies on the non-target analysis of the dust and organic film samples were reported in South Korea.

This research gap is addressed in this study, which uses both target screening by GC-MS to investigate the levels of phthalates and PAHs in samples of settled dust and organic films collected from different residential house types (n = 100) in South Korea, and nontarget screening by GC-QTOF-MS, and the findings of the detected chemicals are discussed. In addition, we examined the relationship between SVOC levels obtained from target screening in indoor dust or organic films and building characteristics, namely, house type, building age, and renovation status.

Section snippets

Chemicals and reagents

The standards of eight phthalates [bis(2-ethylhexyl)phthalate (DEHP), dibutyl phthalate (DBP), dimethylphthalate (DMP), diethylphthalate (DEP), diisobuthyl phthalate (DiBP), butylbenzylphthalate (BBP), di-n-octyl phthalate (DNOP), and di-n-hexyl phthalate (DNHP)] and 16 PAHs (naphthalene, anthracene, fluorene, pyrene, phenanthrene, acenaphthylene, acenaphthene, fluoranthene, benzo[a]antrancene, chrysene, benzo[b,j,k]-fluoranthene benzo[e]pyrene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene,

Levels of SVOCs in dust and organic film samples

Table 1 shows the concentrations of the eight assessed phthalates in house dust and organic film samples. The median concentrations of the phthalates (Σ8 Phthalate) in dust and organic film samples were 1015.93 μg/g and 75.79 μg/m2, respectively. In line with expectations, among these phthalates, DEHP was detected at the highest concentrations in both house dust and organic film samples, with median concentrations of 864.78 μg/g and 58.13 μg/m2, respectively (Table 1), followed by DBP

Conclusions

In this study, we measured the concentrations of SVOCs in dust and organic film samples collected from different housing types. The results showed that the levels of phthalates and PAHs in dust and organic films differ depending on the type of property. The median concentrations of eight phthalates (Σ8phthalate) and 16 polycyclic aromatic hydrocarbons (Σ16PAH) were 1015.93 μg/g and 1824.97 ng/g in dust samples, and 75.79 and 2.25 μg/m2 in organic film samples, respectively. Among the

Credit author statement

Moon-Kyung Kim: Formal analysis, Software, Methodology, Validation, Writing – original draft, Writing – review & editing. Taeyeon Kim: Experiments, Formal analysis, Software, Methodology. Jiseon Choi: Project administration, Conceptualization, Formal analysis. Ye-eun Joo: Experiments, Formal analysis, Sample preparations, Validation. Heungjoo Park: Experiments, Formal analysis, Software, Methodology. Hyewon Lee: Formal analysis, Software, Methodology. Cheolmin Lee: Project administration,

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by the Korea Environment Industry & Technology Institute (KEITI) through the Technology Development Project for Safety Management of Household Chemical Products Program funded by the Korea Ministry of Environment (MOE) (2020002970006, 1485017182 and 2020002970005, 1485018696). The authors would like to thank Ms. Kyungjoo Kim for helping experiments.

References (35)

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