Physicochemical properties and potential health effects of nanoparticles from pulverized coal combustion

Nanoparticles are thought to induce more severe health impacts than larger particles. The nanoparticles from coal-fired boilers are classified into three size fractions with a 13-stage low pressure impactor. Their physicochemical properties are characterized by the high-resolution field emission scanning electron microscope and X-ray fluorescence spectrometer (XRF). The results show that coal-derived nanoparticles mainly consist of individual primary particles of 20–150 nm and their aggregates. Inorganic nanoparticles primarily contain ash-forming elements and their aggregates have a dense structure. Organic nanoparticles are dominated by the element carbon and their aggregates have a loose structure. Nanoparticles from the same boiler have a similar composition and are primarily composed of sulfur, refractory elements and alkali/alkaline elements. Some transition and heavy metals are also detected. For different boilers, greater differences are observed in the production of the nanoparticles and their composition, possibly due to the use of low-NO _x burners. Coal-derived nanoparticles have a small size, large specific surface area and complicated chemical composition, and thus are potentially more harmful to human health. Supported by National Natural Science Foundation of China (Grant Nos. 50721005, 50706013 and 50720145604)