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Source apportionment of fine particulate matter in a Middle Eastern Metropolis, Tehran-Iran, using PMF with organic and inorganic markers

Esmaeilirad, S ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.scitotenv.2019.135330
  3. Publisher: Elsevier B.V , 2020
  4. Abstract:
  5. With over 8 million inhabitants and 4 million motor vehicles on the streets, Tehran is one of the most crowded and polluted cities in the Middle East. Frequent exceedances of national daily PM2.5 limit have been reported in this city during the last decade, yet, the chemical composition and sources of fine particles are poorly determined. In the present study, 24-hour PM2.5 samples were collected at two urban sites during two separate campaigns, a one-year period from 2014 to 2015 and another three-month period at the beginning of 2017. Concentrations of organic carbon (OC), elemental carbon (EC), inorganic ions, trace metals and specific organic molecular markers were measured by chemical analysis of filter samples. The dominant mass components were organic matter (OM), sulfate and EC. With a 20% water-soluble organic carbon (WSOC) fraction, the predominance of primary anthropogenic sources (i.e. fossil fuel combustion) was anticipated. A positive matrix factorization (PMF) analysis using the ME-2 (Multilinear Engine-2) solver was then applied to this dataset. 5 factors were identified by Marker-PMF, named as traffic exhaust (TE), biomass burning (BB), industries (Ind.), nitrate-rich and sulfate-rich. Another 4 factors were identified by Metal-PMF, including, dust, vehicles (traffic non-exhaust, TNE), industries (Ind.) and heavy fuel combustion (HFC). Traffic exhaust was the dominant source with 44.5% contribution to total quantified PM2.5 mass. Sulfate-rich (24.2%) and nitrate-rich (18.4%) factors were the next major contributing sources. Dust (4.4%) and biomass burning (6.7%) also had small contributions while the total share of all other factors was < 2%. Investigating the correlations of different factors between the two sampling sites showed that traffic emissions and biomass burning were local, whereas dust, heavy fuel combustion and industrial sources were regional. Results of this study indicate that gas- and particle-phase pollutants emitted from fossil fuel combustion (mobile and stationary) are the principal origin of both primary and secondary fine aerosols in Tehran. © 2019
  6. Keywords:
  7. Organic markers ; PMF ; Regional/local sources ; Air pollution ; Biomass ; Chemical analysis ; Combustion ; Dust ; Factorization ; Industrial emissions ; Metals ; Nitrates ; Organic carbon ; Particles (particulate matter) ; Sulfur compounds ; Trace elements ; Urban growth ; Anthropogenic sources ; Chemical compositions ; Fine particulate matter ; Fossil fuel combustion ; PM2.5 ; Positive Matrix Factorization ; Water-soluble organic carbon ; Fossil fuels ; Carbon ; Fossil fuel ; Inorganic compound ; Molecular marker ; Nitrate ; Organic compound ; Organic matter ; Sulfate ; Unclassified drug ; Atmospheric pollution ; Concentration (composition) ; Elemental carbon ; Ion ; Source apportionment ; Trace metal ; Article ; Concentration (parameter) ; Controlled study ; Exhaust gas ; Gas ; Industry ; Particulate matter ; Priority journal ; Traffic ; Urban area ; Iran ; Tehran [Iran] ; Tehran [Tehran (PRV)]
  8. Source: Science of the Total Environment ; Volume 705 , 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0048969719353227