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Seasonal trends in the composition and sources of PM2.5 and carbonaceous aerosol in Tehran, Iran

Arhami, M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.envpol.2018.03.111
  3. Publisher: Elsevier Ltd , 2018
  4. Abstract:
  5. Currently PM2.5 is a major air pollution concern in Tehran, Iran due to frequent high levels and possible adverse impacts. In this study, which is the first of its kind to take place in Tehran, composition and sources of PM2.5 and carbonaceous aerosol were determined, and their seasonal trends were studied. In this regard, fine PM samples were collected every six days at a residential station for one year and the chemical constituents including organic marker species, metals, and ions were analyzed by chemical analysis. The source apportionment was performed using organic molecular marker-based CMB receptor modeling. Carbonaceous compounds were the major contributors to fine particulate mass in Tehran, as OC and EC together comprised on average 29% of PM2.5 mass. Major portions of OC in Tehran were water insoluble and are mainly attributed to primary sources. Higher levels of several PAHs, which are organic tracers of incomplete combustion, and hopanes and steranes as organic tracers of mobile sources were obtained in cold months and compared to the warm months. The major contributing source to particulate OC was identified as vehicles, which contributed about 72% of measured OC. Among mobile sources, gasoline-fueled vehicles had the highest impact with a mean contribution of 48% to the measured OC. Mobile sources also were the largest contributor to total PM2.5 (40%), followed by dust (24%) and sulfate (11%). In addition to primary emissions, mobile sources also directly and indirectly played an important role in another 27% of fine particulate mass (secondary organics and ions), which highlights the impact of vehicles in Tehran. Our results highlighted and quantified the role of motor vehicles in fine PM production, particularly during winter time. The results of this study could be used to set more effective regulations and control strategies particularly upon mobile sources. This is the first receptor modeling study to investigate composition and carbonaceous content of fine PM and apportion sources using tracer organics in Tehran. © 2018 Elsevier Ltd
  6. Keywords:
  7. Aerosols ; Air pollution ; Chemical analysis ; Sulfur compounds ; Vehicles ; Carbonaceous aerosol ; Carbonaceous compounds ; Chemical constituents ; CMB receptor model ; Control strategies ; Incomplete combustion ; Primary emissions ; Source apportionment ; Mobile power plants ; Carbon ; Gasoline ; Hopanoid ; Ion ; Metal ; Organic carbon ; Organic matter ; Polycyclic aromatic hydrocarbon ; Prednisolone ; Hydrocarbon ; Atmospheric pollution ; Chemical composition ; Dust ; Sulfate ; Trend analysis ; Article ; Car ; Chemical analysis ; Combustion ; Environmental impact ; Motor vehicle ; Residential area ; Seasonal variation ; Trend study ; Winter ; Aerosol ; Air pollutant ; Analysis ; Chemistry ; Human activities ; Procedures ; Season ; Theoretical model ; Tehran [Iran] ; Air Pollutants ; Environmental Monitoring ; Human Activities ; Hydrocarbons ; Iran ; Models, Theoretical ; Particle Size ; Particulate Matter ; Seasons
  8. Source: Environmental Pollution ; Volume 239 , 2018 , Pages 69-81 ; 02697491 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0269749117353484?via%3Dihub