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: 5.509 IF 5.509
  • IF 5-year value: 5.689 IF 5-year 5.689
  • CiteScore value: 5.44 CiteScore 5.44
  • SNIP value: 1.519 SNIP 1.519
  • SJR value: 3.032 SJR 3.032
  • IPP value: 5.37 IPP 5.37
  • h5-index value: 86 h5-index 86
  • Scimago H index value: 161 Scimago H index 161
Discussion papers | Copyright
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 12 Oct 2018

Research article | 12 Oct 2018

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).

Sources of Airborne Ultrafine Particle Number and Mass Concentrations in California

Xin Yu1, Melissa Venecek2, Jianlin Hu3, Saffet Tanrikulu4, Su-Tzai Soon4, Cuong Tran4, David Fairley4, and Michael J. Kleeman1 Xin Yu et al.
  • 1Department of Civil and Environmental Engineering, University of California, Davis. One Shields Avenue, Davis CA, USA
  • 2Department of Land, Air, and Water Resources, University of California, Davis. One Shields Avenue, Davis CA, USA
  • 3School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Pukou, Nanjing, China
  • 4Bay Area Air Quality Management District, San Francisco, CA, USA

Abstract. Regional concentrations and source contributions are calculated for airborne particle number concentration (PNC) and ultrafine particle mass concentration (PM0.1) in the San Francisco Bay Area (SFBA) and the South Coast Air Basin (SoCAB) surrounding Los Angeles with 4km spatial resolution and daily time resolution for selected months in the years 2012, 2015, and 2016. Performance statistics for daily predictions of PNC concentrations meet the threshold normally required for regulatory modeling of PM2.5 (MFB<±0.5 and MFE<0.75). Predicted source contributions to PM0.1 are in good agreement with results from receptor-based studies that use molecular markers for source apportionment at four locations in California. Different sources dominated regional concentrations of PNC and PM0.1 because of the different emitted particle size distributions and different choices for heating fuels. Non-residential natural gas combustion (38–74%) made the largest single contribution to PNC concentrations at the ten regional monitoring locations, followed by nucleation (6–14%), wood smoke (1–8%), food cooking (1–9%), and mobile sources (4–8%). In contrast, wood smoke (25–49%) was the largest source of PM0.1 in the SFBA followed by mobile sources (15–33%), non-residential natural gas combustion (13–28%), and food cooking (4%–14%). Non-residential natural gas combustion (42–57%) was the largest PM0.1 source at the SoCAB sites, followed by traffic sources (16–35%) and food cooking (6–14%). The study region encompassed in this project is home to more than 25M residents, which should provide sufficient power for future epidemiological studies on the health effects of airborne ultrafine particles. Correlations between PM2.5 and PNC are low (R2=0.35) suggesting that the health effects of these metrics may be assessed independently. All of the PM0.1 and PNC outdoor exposure fields produced in the current study are available free of charge at

Xin Yu et al.
Interactive discussion
Status: open (until 07 Dec 2018)
Status: open (until 07 Dec 2018)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Xin Yu et al.
Total article views: 207 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
167 39 1 207 7 0 0
  • HTML: 167
  • PDF: 39
  • XML: 1
  • Total: 207
  • Supplement: 7
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 12 Oct 2018)
Cumulative views and downloads (calculated since 12 Oct 2018)
Viewed (geographical distribution)
Total article views: 207 (including HTML, PDF, and XML) Thereof 207 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
No saved metrics found.
No discussed metrics found.
Latest update: 21 Oct 2018
Publications Copernicus
Short summary
Predictions and measurements of ultrafine particle number and mass concentrations were in overall good agreement at fourteen sites across California in the years 2012, 2015, and 2016. On-road vehicles, food cooking, and aircraft were important source of ultrafine particles as expected, but natural gas combustion was also a significant source at all locations across California. These results can be used to study the health-effects studies for ultrafine particles.
Predictions and measurements of ultrafine particle number and mass concentrations were in...