Emission characteristics and associated health risks from polyolefin extrusion blow molding in detergent plastic manufacturing

Polymer molding for detergent plastic products is an important yet insufficiently characterized source of atmospheric particles and co-occurring chemical pollutants. We quantified airborne particles and five chemical pollutant classes across 53 fixed locations in a polypropylene and polyethylene extrusion blow molding facility under identical operating conditions, integrating particle size distributions, total suspended particle mass, and ultrafine fractions. Emissions were strongly process-stage dependent, with polymer melting and extrusion blow molding dominating release. Peak concentrations reached styrene 1104.63 ± 58.12 µg·m^-3, toluene 724.45 ± 33.52 µg·m^-3, Fe 27.15 ± 12.88 µg·m^-3, SO₄^2- 96.32 ± 32.34 µg·m^-3, DEHP 298.14 ± 79.59 µg·m^-3, and PFOA 148.90 ± 13.01 ng·m^-3. Particle size distributions diverged sharply by process function, shifting toward ultrafine sizes during extrusion blow molding, with number concentrations peaking at 5.96 × 10⁶ ·cm^-3 at 107 nm and coinciding with maximum particulate mass and number burdens of 3.63 × 10⁴ µg·m^-3 and 2.94 × 10⁸·cm^-3. Nanoparticles accounted for 26% of total particle numbers in melt-dominated stages but less than 13% downstream. Particle mass, number, and nanoscale fractions were strongly coupled (TSP-TPC r = 0.894; TSP-NPN r = 0.876). Health risk indicators were concentrated in melt-intensive stages, with non-carcinogenic risk driven by styrene (HQ up to 1.02 × 10²) and carcinogenic risk by benzene (ELCR up to 4.86 × 10^-2). Overall, localized thermal conditions organize coupled particles, chemicals, and process-prioritized exposure patterns in detergent plastic extrusion blow molding.