PM_1.0 marker-based diagnostic ratios and PMF-based source apportionment for quantifying oxidative potential in a...

Combustion remains an important yet hazardous source of emissions, and isolating its contribution to ambient PM_1.0 is challenging because polycyclic aromatic hydrocarbons (PAHs) are emitted from multiple combustion sources. PM_1.0 was collected at 6 h resolution (n = 162) in western Korea from September 8 to October 18, 2024, near major point sources. The chemical composition, molecular markers (levoglucosan, mannosan, terephthalic acid, dehydroabietic acid, 6PPD-Q), PAHs including picene, and dithiothreitol-based oxidative potential (QDTT-OP) were measured, and source contributions were resolved using positive matrix factorization (PMF). PMF identified PET waste combustion (28.8%) and wood waste combustion (18.1%), while coal combustion accounted for just 4.1% of PM_1.0 mass. Despite its low mass fraction, the chemical influence of coal was evident. Conventional PAH ratio analysis revealed the co-occurrence of elevated picene and higher QDTT-OP in combustion-dominated domains. A PMF-constrained diagnostic framework was developed using picene-normalized ratios and a scaled composite marker, LMT*, defined as LMT/1000, where LMT is the sum of levoglucosan, mannosan, and terephthalic acid. PAHs were categorized into L-PAHs and H-PAHs. The proposed screening thresholds were Pic/(Pic + L-PAHs) ≥ 0.06 for coal combustion and LMT*/(LMT* + L-PAHs) ≥ 0.10 for PET and wood waste combustion.