Additive fingerprinting of airborne plastic-related particulate matter in occupational environments: Insights from targeted and untargeted analysis

This study aimed to assess the potential of polymer additives as chemical markers of plastic-related emissions in airborne particulate matter in occupational environments, within the broader context of airborne micro- and nanoplastics (MNPs). Particulate matter collected in three facilities— a textile production (FTX, Facility – Textile), a mineral water bottling plant (FBW, Facility-Bottling Water) and a tyre service and repair facility (FTR, Facility – Tyre Repair)—was investigated to explore the relationship between polymer additives and particulate composition. Samples from multiple sites and size fractions were analysed using a combined targeted and high-resolution untargeted GC-MS approach to characterise plastic additives (e.g. phthalates, alternative plasticisers, antioxidants, UV filters) and related organic compounds. Distinct chemical fingerprints were observed for each facility: FTX was characterised by high-molecular-weight phthalates and terephthalates, with mean concentrations of 5.8 ng/m³ for DEHP and 4.3 ng/m³ for diethyl terephthalate. FBW was dominated by citrate- and adipate-based plasticisers, where acetyl tributyl citrate and di(2-ethylhexyl) adipate showed a mean concentration of 9.4 ng/m 3 and 1.7 ng/m 3 , respectively. FTR showed higher levels of tyre-derived antioxidants and rubber markers, such as tris(2,4-di-tert-butylphenyl) phosphate (mean: 20 ng/m 3 ), 6PPD (3.3 ng/m 3 ), and benzothiazole (1.5 ng/m³). Size-resolved analysis showed enrichment of additives in fine fractions at FTX and in coarse fractions at FTR, reflecting process-specific emission mechanisms. Untargeted screening revealed a complex mixture including auxiliary materials, lubricants, surface treatments and other process-related compounds, providing a comprehensive characterisation of indoor particulate composition. Overall, the results demonstrate that the combined targeted and untargeted chemical profiles reflect site-specific processes and materials, allowing the discrimination of different emission scenarios across the investigated facilities.