Personal exposure to microplastics and PAHs in PM_2.5: Personal vs. outdoor assessment and health risks

Microplastics (MPs) and polycyclic aromatic hydrocarbons (PAHs) are pervasive emerging pollutants in the environment, raising growing concerns about their adverse health effects. However, research on characterizing MPs in fine particulate matter (PM_2.5) remains scarce due to methodological challenges. This study quantified human exposure to MPs and PAHs in PM_2.5 in Shanghai, a megacity in China, using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and GC/MS, respectively. The average concentration of personal exposure MPs reached 2.27 ± 2.31 μg m^-3, which appeared to be higher than outdoor levels (0.69 ± 0.58 μg m^-3). Polyethylene (PE) was the dominant polymer in both environments, with personal exposure samples exhibiting higher proportions of polyethylene terephthalate (PET) and polystyrene (PS). Relative humidity had a significant impact on outdoor MP concentrations, whereas personal exposure MP levels were primarily affected by indoor sources and ventilation conditions. In contrast, the average concentration of outdoor PAHs (45.76 ± 35.02 ng m^-3) was 50 % higher than the personal one (30.67 ± 8.67 ng m^-3). A significant positive correlation between polypropylene (PP) and low-molecular-weight PAHs suggests potential adsorption or common sources. Estimated daily intake (EDI) assessment revealed higher exposure levels to MPs than PAHs, underscoring the urgent need for an in-depth understanding of inhalable MPs/NPs and their additives.