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. 2025 May 31;13(6):467.
doi: 10.3390/toxics13060467.

Distribution, Sources, and Health Risk of Short-, Medium- and Long-Chain Chlorinated Paraffins in School-Area Ambient PM1: A Study from the Pearl River Delta, China

Mo Yang  1   2 , Xin-Feng Wang  3 , Jing-Wen Huang  2 , Nan-Xiang Jin  4 , Chu Chu  1   2 , Guo-Feng Huang  5 , Duo-Hong Chen  5 , Min Xie  5 , Yu-Hong Zhai  5 , Yu-Jun Lin  5 , Jun Liu  5 , Li-Zi Lin  2 , Wen-Wen Bao  2 , Zhao-Huan Gui  2 , Pasi I Jalava  1 , Guang-Hui Dong  2   6 , Marjut Roponen  1
Affiliations

Distribution, Sources, and Health Risk of Short-, Medium- and Long-Chain Chlorinated Paraffins in School-Area Ambient PM1: A Study from the Pearl River Delta, China

Mo Yang et al. Toxics. .

Abstract

Background: Only a few studies have reported on chlorinated paraffin (CP) levels, especially long-chain chlorinated paraffins (LCCPs), in submicron particulate matter (PM1) in the outdoor air around primary and secondary schools.

Methods: This study examined concentrations of short-chain CPs (SCCPs), medium-chain CPs (MCCPs), and LCCPs in PM1 samples from 96 schools across six cities in China's Pearl River Delta region during the winter (October to December 2018).

Results: The median total CP concentration was 34 ng/m3, with median values for SCCP, MCCP, and LCCP of 17.3, 15, and 0.7 ng/m3, respectively. The primary congeners were C13Cl6-8 for SCCPs, C14Cl6-9 for MCCPs, and C18Cl7-10 for LCCPs. The SCCPs and MCCPs largely originated from fugitive dust, whereas the LCCPs were mainly sourced from organic chemical industries. Air masses from the South China Sea contributed most to SCCP and MCCP levels, while those from the east coast accounted for the highest LCCP levels. The concentrations of CP in PM1 were significantly positively correlated with PM1 levels.

Conclusions: The exposure risk assessments by age indicated a very low current health risk from PM1-related CP inhalation, although prolonged pollution could raise these risks as CP concentrations in ambient PM may continue to increase.

Keywords: ambient PM1; children; chlorinated paraffins; health risk; source.

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Conflict of interest statement

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.

Figures

Figure 1
Figure 1
(A,B) Relative abundance profiles of congener groups for SCCPs, MCCPs, and LCCPs in PM1 samples collected from the Pearl River Delta region, China. The profiles are grouped based on carbon chain length and number of chlorine atoms. (C) Distribution of alkane chains (C10–C13 for SCCPs, C14–C17 for MCCPs, and C18–C30 for LCCPs). Data are presented as mean and range, indicating the relative contribution (%) of each chain length within its respective CP class. (D) Chlorine content (%) of SCCPs, MCCPs, and LCCPs, shown as mean and range. (E) Chlorination level (average number of Cl atoms per molecule) for each CP class, highlighting the degree of chlorination. Asterisks (**) indicate statistically significant differences between groups (p < 0.001).
Figure 2
Figure 2
Contributions of secondary formation and combustion, metal smelting, traffic sources, crustal dust, sea salts, fugitive dust, and organic chemical industries to the sources of SCCPs, MCCPs, LCCPs, and other components in PM1 from six cities in the Pearl River Delta, China (A). (B–D): The contributions of seven sources to SCCPs, MCCPs, and LCCPs. The data are percentages (%) from different sources.
Figure 3
Figure 3
Backward trajectories of air masses and the concentrations of SCCPs, MCCPs, and LCCPs in PM1 in the Pearl River Delta, China from different air mass directions. The values in the histograms refer to the concentrations (ng/m3) of SCCPs, MCCPs, and LCCPs.
Figure 4
Figure 4
(A) Age-specific estimated daily intakes (EDIs) and (B) hazard quotients (HQs) of ΣCPs through PM1 inhalation. Solid lines indicate the median of each group.
See this image and copyright information in PMC

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