High-Resolution Characterization of Coal Combustion-Derived Metal-Containing Nanoparticles and Their Health-Related Implications

Precise determination of the elemental composition of metal-containing nanoparticles (MCNPs) emitted from coal combustion is imperative for evaluating their health implications. Utilizing single-particle ICP time-of-flight MS, this study analyzed elemental compositions of individual MCNPs in coal combustion byproducts (CCPs) collected from a typical coal-fired power plant (CFPP). Vast Ti-, Fe-, Zn-, and Pb-containing NPs were identified in CCPs, with the fly ash escaping through the stack (EFA) exhibiting the highest particle number concentrations. Notably, 65%-100% of these MCNPs were multimetals ones. Zn and Pb were predominantly present in mass fractions below 10% within individual particles, indicating their adsorption onto MCNPs. Al, Si, and Fe were the dominant components of MCNPs. Volatile toxic metals associated with these MCNPs increased with dust removal stages and reached the highest in EFA. Compared to MCNPs in the first dust removal stage, oxidative stress and cytotoxicity of MCNPs in EFA increased by 78% and 32%, respectively. Cytotoxicity was approximately 14 times higher than that of PM_2.5 emitted from CFPPs. Iron in Al-rich NPs and Fe-rich NPs emerged as the top significant factors regulating intracellular oxidative stress, while trace metals (especially Pb) associated with MCNPs played the most important role in lung cell viability toxicity.