Three-Year Long Source Apportionment Study of Airborne Particles in Ulaanbaatar Using X-Ray Fluorescence and Positive Matrix Factorization

Abstract

The capital city of Mongolia, Ulaanbaatar, suffers from high levels of pollution due to excessive airborne particulate matter (APM). A lack of systematic data for the region has inspired investigation into the type, origin and seasonal variations of this pollution, the effects of meteorological conditions and even the time-dependence of anthropogenic sources. This work reports source apportionment results from a large data set of 184 samples each of fine (PM 2.5 ) and coarse (PM 2.5-10 ) fraction atmospheric PM collected over a three-year period (2014)(2015)(2016) in Ulaanbaatar, Mongolia. Positive Matrix Factorization (PMF) was applied using the concentrations of 16 elements measured by an energy dispersive X-ray fluorescence spectrometer along with the black carbon content measured by a reflectometer as input data. The PMF results revealed that whereas mixed sources dominate the coarse fraction, soil and traffic sources are the principle contributors to the fine fraction. The source profiles and the seasonal variations of their contributions indicate that fly ash emanating from coal combustion mixes with traffic emissions and resuspended soil, resulting in variable chemical source profiles. Four sources were identified for both fractions, namely, soil, coal combustion, traffic and oil combustion, which respectively contributed 35%, 16%, 41% and 8% to the coarse fraction and 31%, 27%, 31% and 11% to the fine fraction. Additionally, the probable source contributions from long-range transport events were assessed via concentration-weighted trajectory analysis.

Quantitative assessment of the variability in chemical profiles from source apportionment analysis of PM10 and PM2.5 at different sites within a large metropolitan area

“…Positive Matrix Factorization (PMF) is a widely used source apportionment tool based on receptor modeling (Hopke, 2016). PMF is very reliable, as documented by European intercomparison exercises (Belis et al, 2015a(Belis et al, ,b, 2020, and has been used in a very large number of studies around the world (Diapouli et al, 2017b(Diapouli et al, , 2017aGunchin et al, 2019;Kim et al, 2003;Pateraki et al, 2019;Waked et al, 2014).…”

Source Apportionment of Fine Organic and Inorganic Atmospheric Aerosol in an Urban Background Area in Greece

“…The process of identifying PM sources is called source apportionment and there is a wide range of methods that have been proposed based on the available measurements [6]. A widely used source apportionment approach is the use of various types of source-receptor models [7][8][9][10][11]. Most receptor models are based on the assumption that at the receptor site, the time dependence of the concentration of PM components originating from the same source will be the same.…”

Chromium and Zinc Speciation in Airborne Particulate Matter Collected in Ulaanbaatar, Mongolia, by X-Ray Absorption Near-edge Structure Spectroscopy

“…Atmospheric particles were collected on polycarbonate filters at the air quality monitoring site, 4 kilometers east of the center of Ulaanbaatar (latitude 47 o .55', longitude 106 o .55', 1300 m above sea level). More information about the sampling site is described in Gunchin et al, 2019. In total, fifty-two samples were collected, twice a week (every Monday and Thursday) throughout the period June 2016 to January 2017.…”

“…Selections were based on the highest relevance when these elements were found at elevated concentrations. The elemental analysis of the fine and course PM samples was performed by means of the Panalytical Epsilon 5 Energy Dispersive X-ray Fluorescence Analysis (EDXRF) spectrometer at the premises of the Nuclear Science and Instrumentation Laboratory of the International Atomic Energy Agency (IAEA), Seibersdorf, Austria (Gunchin et al, 2019). The spectrometer features various secondary targets, such as Al, CaF2, Fe, Ge, Zr, Mo, Ag and Al2O3 (Barkla polarization target) which are irradiated by a 600 W Sc-W anode X-ray tube.…”