The relative contributions of traffic and non-traffic sources in ultrafine particle formations in Tehran mega city

Farzaneh Jafarigol; Somayeh Yousefi; Ali Darvishi Omrani; Yousef Rashidi; Giorgio Buonanno; Luca Stabile; Sergei Sabanov; Mehdi Amouei Torkmahalleh

doi:10.1038/s41598-023-49444-z

The relative contributions of traffic and non-traffic sources in ultrafine particle formations in Tehran mega city

Sci Rep. 2024 May 6;14(1):10399. doi: 10.1038/s41598-023-49444-z.

Authors

Farzaneh Jafarigol¹, Somayeh Yousefi², Ali Darvishi Omrani³, Yousef Rashidi⁴, Giorgio Buonanno^{5

6}, Luca Stabile⁵, Sergei Sabanov⁷, Mehdi Amouei Torkmahalleh⁸

Affiliations

¹ Department of Chemical and Materials Engineering, School of Engineering and Digital Sciences, Nazarbayev University, Astana, Kazakhstan.
² Department of Environmental Technologies, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran.
³ Independent Researcher, Sari, Mazandaran, 48197, Iran.
⁴ Department of Environmental Technologies, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran. [email protected].
⁵ Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy.
⁶ International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia.
⁷ Department of Mining Engineering, School of Mining and Geosciences, Nazarbayev University, Astana, Kazakhstan.
⁸ Division of Environmental and Occupational Health Sciences, School of Public Health, University of Illinois at Chicago, Chicago, IL, 60612, USA.

Abstract

Emissions of ultrafine particles (UFPs; diameter < 100 nm) are strongly associated with traffic-related emissions and are a growing global concern in urban environments. The aim of this study was to investigate the variations of particle number concentration (PNC) with a diameter > 10 nm at nine stations and understand the major sources of UFP_s (primary vs. secondary) in Tehran megacity. The study was carried out in Tehran in 2020. NOx and PNC were reported from a total of nine urban site locations in Tehran and BC concentrations were examined at two monitoring stations. Data from all stations showed diurnal changes with peak morning and evening rush hours. The hourly PNC was correlated with NOx. PNCs in Tehran were higher compared to those of many cities reported in the literature. The highest concentrations were at District 19 station (traffic) and the lowest was at Punak station (residential) such that the average PNC varied from 8.4 × 10³ to 5.7 × 10⁴ cm^-3. In Ray and Sharif stations, the average contributions of primary and secondary sources of PNC were 67 and 33%, respectively. Overall, we conclude that a decrease in primary emission leads to a decrease in the total concentration of aerosols, despite an increase in the formation of new particles by photo nucleation.