Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.668 IF 5.668
  • IF 5-year value: 6.201 IF 5-year
    6.201
  • CiteScore value: 6.13 CiteScore
    6.13
  • SNIP value: 1.633 SNIP 1.633
  • IPP value: 5.91 IPP 5.91
  • SJR value: 2.938 SJR 2.938
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 174 Scimago H
    index 174
  • h5-index value: 87 h5-index 87
Discussion papers
https://doi.org/10.5194/acp-2019-458
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-2019-458
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 23 Jul 2019

Submitted as: research article | 23 Jul 2019

Review status
This discussion paper is a preprint. A revision of this manuscript was accepted for the journal Atmospheric Chemistry and Physics (ACP) and is expected to appear here in due course.

Traffic-originated nanocluster emission exceeds H2SO4-driven photochemical new particle formation in an urban area

Miska Olin1, Heino Kuuluvainen1, Minna Aurela2, Joni Kalliokoski1, Niina Kuittinen1, Mia Isotalo1, Hilkka J. Timonen2, Jarkko V. Niemi3, Topi Rönkkö1, and Miikka Dal Maso1 Miska Olin et al.
  • 1Aerosol Physics Laboratory, Physics Unit, Tampere University, FI-33014 Tampere, Finland
  • 2Atmospheric Composition Research, Finnish Meteorological Institute, FI-00101 Helsinki, Finland
  • 3Helsinki Region Environmental Services Authority (HSY), FI-00066 HSY, Finland

Abstract. Elevated ambient concentrations of sub-3 nm particles (nanocluster aerosol, NCA) are generally related to atmospheric new particle formation events, usually linked with gaseous sulfuric acid (H2SO4) produced via photochemical oxidation of sulfur dioxide. According to our measurement results of H2SO4 and NCA concentrations, traffic density, and solar irradiance at an urban traffic site in Helsinki, Finland, the view of aerosol formation in traffic-influenced environments is updated by presenting two separate and independent pathways of traffic affecting the atmospheric NCA concentrations: by acting as a direct nanocluster source, and by influencing the production of H2SO4. As traffic density is frequently correlated with solar radiation, it is likely that the influence of traffic-related nanoclusters has been hidden in the diurnal variation, and is thus underestimated because new particle formation events also follow the diurnal cycle of sunlight. Urban aerosol formation studies should, therefore, be updated to include the proposed formation mechanisms. Additionally, the directly emitted NCA poses a potentially elevated health risk, highlighting the need for quantifying the source and loadings in populated areas. The formation of H2SO4 in urban environments is here separated in two routes: primary H2SO4 is formed in hot vehicle exhaust and is converted rapidly to particle phase; secondary H2SO4 results from the combined effect of emitted gaseous precursors and available solar radiation.

Miska Olin et al.
Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Miska Olin et al.
Viewed  
Total article views: 520 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
395 121 4 520 17 2 6
  • HTML: 395
  • PDF: 121
  • XML: 4
  • Total: 520
  • Supplement: 17
  • BibTeX: 2
  • EndNote: 6
Views and downloads (calculated since 23 Jul 2019)
Cumulative views and downloads (calculated since 23 Jul 2019)
Viewed (geographical distribution)  
Total article views: 453 (including HTML, PDF, and XML) Thereof 450 with geography defined and 3 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 07 Dec 2019
Publications Copernicus
Download
Short summary
Photochemically formed sulfuric acid is generally considered the main source for new particle formation in the atmosphere. Contrary to current understanding, our measurements of nanoclusters and gaseous sulfuric acid performed in an urban area imply that traffic contributes to sulfuric acid concentration, and that even for the smallest particles, the traffic-emitted fraction mostly exceeds the photochemistry-driven regional new particle formation.
Photochemically formed sulfuric acid is generally considered the main source for new particle...
Citation