Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2017-199
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
07 Mar 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
A new balance formula to estimate new particle formation rate: reevaluating the effect of coagulation scavenging
Runlong Cai and Jingkun Jiang State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
Abstract. A new balance formula to estimate new particle formation rate is proposed. It was derived from aerosol general dynamic equation in the discrete form and then converted into an approximately continuous form for analysing data from new particle formation (NPF) field campaigns. The new formula corrects the underestimation of the coagulation scavenging effect occurred in previously used formulae. It also clarifies the criterions in determining upper size bound in measured aerosol size distributions for estimating new particle formation rate. A NPF field campaign was carried out from March 7th to Apr. 7th, 2016, in urban Beijing, and a diethylene glycol scanning mobility particle spectrometer equipped with a miniature cylindrical differential mobility analyser was used to measure aerosol size distributions down to ~1 nm. 11 typical NPF events were observed during this period. Measured aerosol size distributions from 1 nm to 10 μm was used to test the new formula and those widely used ones. Previously used formulae that perform well in relatively clean atmosphere where nucleation intensity is not strong were found to underestimate the comparatively high new particle formation rate in urban Beijing because of their underestimation or neglect of the coagulation scavenging effect. Coagulation sink term is the governing component of the estimated formation rate in the observed NPF events in Beijing, and coagulation among newly formed particles contributes a large fraction to the coagulation sink term. Previously reported formation rates in Beijing and in other locations with intense NPF events might be underestimated because the coagulation scavenging effect was not fully considered, e.g., formation rates of 1.5 nm particles in Beijing are underestimated by 58.9 % on average if neglecting coagulation among particles in nucleation mode.

Citation: Cai, R. and Jiang, J.: A new balance formula to estimate new particle formation rate: reevaluating the effect of coagulation scavenging, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-199, in review, 2017.
Runlong Cai and Jingkun Jiang
Runlong Cai and Jingkun Jiang
Runlong Cai and Jingkun Jiang

Viewed

Total article views: 459 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
208 212 39 459 13 38

Views and downloads (calculated since 07 Mar 2017)

Cumulative views and downloads (calculated since 07 Mar 2017)

Viewed (geographical distribution)

Total article views: 459 (including HTML, PDF, and XML)

Thereof 457 with geography defined and 2 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 27 May 2017
Publications Copernicus
Download
Short summary
We found that widely used formulae underestimate atmospheric new particle formation (NPF) rate when analysing intense NPF events. It is caused by the underestimation or neglect of the coagulation scavenging effect. To address this issue, a new formula was theoretically derived. Aerosol down to ~ 1 nm was measured in Beijing. They were used together with literature reported data to test this new formula and others. Implications in NPF rates in various atmosphere environment are discussed.
We found that widely used formulae underestimate atmospheric new particle formation (NPF) rate...
Share