Abstract:

Samples of atmospheric particulate matter from solid fuel (coal and wood) combustion were collected in the high lung cancer incidence area of Xuanwei, Yunnan, and 796 particles emitted by combustion were analysed by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). According to the microscopic characteristics and chemical element compositions of the particles, the particles were divided into four categories, namely mineral particles, fly ash, soot aggregates, and unidentified particles. The $P$(X) method was used to further classify the mineral particles into eight different types, namely Si-rich, S-rich, Ca-rich, Fe-rich, Ti-rich, Al-rich, Na-rich, and others. The percentages of Si-rich, Ca-rich, Fe-rich, and S-rich particles in coal-fired particulate matter and combustion biomass particles accounted for 44.47%, 20.49%, 8.85%, 1.22% and 55.91%, 17.27%, 6.36%, 2.27%, respectively. The chemical analysis results showed that the mass concentrations of the crustal elements Al, Fe, Ca, and Mg in the particles were relatively high, and the mass concentrations of heavy metal elements were relatively low. There was a positive correlation ($R^{2}=0.63$) between the results of the chemical analysis of particulate matter emitted from coal combustion and the results of single particle analysis.

Key words: lung cancer, solid fuel, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), $P$($X$) value