X-ray diffraction as a major tool for the analysis of PM2.5 and PM10 aerosols

Particulate matter (PM) specimens from a traffic site were sampled on Teflon filters using a low volume sampler. The sampling campaign ran over a one-year period with sampling frequency of twice a week for both PM2.5 and PM10. X-ray diffraction (XRD) methods, which are not commonly used in PM analysis, have been utilized successfully to identify crystalline phases present, including secondary pollutants. XRD data confirmed results obtained by X-ray fluorescence, positive matrix factorization modeling, and scanning electron microscopy. PM2.5 consisted mainly of secondary sulfates, like Mascagnite [(NH4)(2)SO4], Koktaite [(NH4)(2)Ca(SO4)(2)center dot H2O], and Gypsum [CaSO4 center dot 2H(2)O]. For PM10, it was found that the major phases are mostly originating from natural sources, such as dust storms and sea salts, in addition to secondary compounds, such as sodium nitrate. The main phases identified were Calcite, Quartz, Gypsum, Halite, and Palygorskite. (C) The Author(s), 2020. Published by Cambridge University Press on behalf of International Centre for Diffraction Data.