Quantitative source apportionment and health risk assessment for polycyclic aromatic hydrocarbon and their derivatives in indoor dust from housing and public buildings of a mega-city in China

Indoor dust can adsorb various pollutants and long-term deposition can significantly impact air quality and human health. This study investigated the occurrence, source apportionment, and health risks associated with polycyclic aromatic hydrocarbons (PAHs) and their derivatives (d-PAHs) in indoor dust, by focusing on residential and public buildings in Nanjing, China. The concentration of 16 PAHs and 27 d-PAHs ranged from 511 to 5472 ng/g and from 422 to 2904 ng/g, with the most abundant compounds being fluoranthene and 1,2-benz[a]anthraquinone, respectively. The total concentrations observed in residences and station halls were higher than in student dormitory and offices. The primary source of PAHs and d-PAHs was identified as coal combustion by self-organizing map combined with receptor models, including principal component analysis-multiple linear regression (PCA-MLR) and positive matrix factorization (PMF). Compared with PCA-MLR, PMF demonstrated superior performance and was recommended as the preferred model for quantitative source analysis. PAHs and d-PAHs in indoor dust may pose a high incremental lifetime carcinogenic risk (˃ 1 × 10−4) through inhalation and dermal exposure based on Monte Carlo simulation. PAH derivatives posed a risk of 70 % of the total target compounds, although their concentration only accounted for 30 %. Notably, children exhibited a higher risk through ingestion than adults, which can be attributed to hand-to-mouth and object-to-mouth contact behaviors. This work helps to understand PAHs and d-PAHs in urban indoor dust from both outdoor environments and indoor activities, offering an innovative perspective for tracing indoor environmental pollution sources and risks. [Display omitted] •PAHs, NPAHs, OPAHs, and HPAHs were monitored in indoor dust in Nanjing.•Indoor dust from residence exhibited relatively high concentrations.•PAHs and derivatives in indoor dust were primarily derived from coal combustion.•The health risk for dermal contact and ingestion was higher than acceptable levels.