Environmental Impact and Risk Assessment of Phthalate Contamination in Indoor Dust and PM₁₀ from Car Repair Workshops

Phthalates are widely used plasticizers that readily migrate from indoor materials into dust and airborne particles, potentially posing health risks for workers in small enterprises such as car repair shops. This study assessed the concentrations of 13 phthalate esters in indoor dust and PM₁₀ from car repair workshops in Jeddah, Saudi Arabia, and estimated occupational exposure for adult workers. Floor dust samples were collected from multiple car repair workshops using a standard vacuum-based sampling method. Indoor PM₁₀ wassimultaneously sampled on quartz fiber filters using a Micro-Environmental Monitor 400, and all samples were analyzed by gas chromatography–mass spectrometry (GC–MS). All target phthalates were frequently detected in both matrices, with substantially higher levels in dust than in PM₁₀. In dust, di(2-ethylhexyl) phthalate (DEHP) was the predominant compound, with mean and maximum concentrations of 4.1×10⁵ and 8.0×10⁵ ng/g, respectively, followed by benzyl butyl phthalate (BzBP) and diethyl phthalate (DEP). In PM₁₀, DEHP also dominated (mean 2.8×10³ ng/g), with notable contributions from Di-isobutyl phthalate (DiBP), DEP, and dimethyl phthalate (DMP). Combined exposure through dust ingestion and inhalation was primarily driven by DEHP (median 538 ng/kg bw/day; 90th percentile 1055 ng/kg bw/day), while other phthalates, including BzBP, DEP, DiBP, DMP, and di-n-octyl phthalate (DnOP), contributed appreciably to the cumulative phthalate burden. The exceptionally high DEHP levels in dust, coupled with measurable airborne concentrations, indicate an intense use or continuous presence of DEHP-containing materials, lubricants, and plastic components in car repair environments. The estimated occupational exposures approach, and in some cases exceed, those reported for other high-contact indoor micro-environments, highlighting car repair shops as an overlooked yet significant source of phthalate exposure for adults. These findings highlight the need for better material selection, improved ventilation, personal protective equipment, and stronger hygiene practices to reduce phthalate exposure among auto-repair workers in similar settings.