Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 18, 311-326, 2018
https://doi.org/10.5194/acp-18-311-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
11 Jan 2018
Vertically resolved concentration and liquid water content of atmospheric nanoparticles at the US DOE Southern Great Plains site
Haihan Chen1, Anna L. Hodshire2, John Ortega3, James Greenberg3, Peter H. McMurry4, Annmarie G. Carlton1, Jeffrey R. Pierce2, Dave R. Hanson5, and James N. Smith1 1Department of Chemistry, University of California, Irvine, 92697, USA
2Department of Atmospheric Science, Colorado State University, Fort Collins, 80523, USA
3National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling Laboratory, Boulder, 80307, USA
4Department of Mechanical Engineering, University of Minnesota-Twin Cities, Minneapolis, 55455, USA
5Department of Chemistry, Augsburg University, Minneapolis, 55454, USA
Abstract. Most prior field studies of new particle formation (NPF) have been performed at or near ground level, leaving many unanswered questions regarding the vertical extent of NPF. To address this, we measured concentrations of 11–16 nm diameter particles from ground level to 1000 m during the 2013 New Particle Formation Study at the Atmospheric Radiation Measurement Southern Great Plains site in Lamont, Oklahoma. The measurements were performed using a tethered balloon carrying two condensation particle counters that were configured for two different particle cut-off diameters. These observations were compared to data from three scanning mobility particle sizers at the ground level. We observed that 11–16 nm diameter particles were generated at the top region of the boundary layer, and were then rapidly mixed throughout the boundary layer. We also estimate liquid water content of nanoparticles using ground-based measurements of particle hygroscopicity obtained with a Humidified Tandem Differential Mobility Analyzer and vertically resolved relative humidity (RH) and temperature measured with a Raman lidar. Our analyses of these observations lead to the following conclusions regarding nanoparticles formed during NPF events at this site: (1) ground-based observations may not always accurately represent the timing, distribution, and meteorological conditions associated with the onset of NPF; (2) nanoparticles are highly hygroscopic and typically contain up to 50 % water by volume, and during conditions of high RH combined with high particle hygroscopicity, particles can be up to 95 % water by volume; (3) increased liquid water content of nanoparticles at high RH greatly enhances the partitioning of water-soluble species like organic acids into ambient nanoparticles.

Citation: Chen, H., Hodshire, A. L., Ortega, J., Greenberg, J., McMurry, P. H., Carlton, A. G., Pierce, J. R., Hanson, D. R., and Smith, J. N.: Vertically resolved concentration and liquid water content of atmospheric nanoparticles at the US DOE Southern Great Plains site, Atmos. Chem. Phys., 18, 311-326, https://doi.org/10.5194/acp-18-311-2018, 2018.
Publications Copernicus
Download
Short summary
Much of what we know about atmospheric new particle formation (NPF) is based on ground-level measurements. We used tethered balloon measurements and remote sensing to study the location in the boundary layer in which NPF events are initiated, the degree to which the boundary layer is well-mixed during NPF, and the potential role that water may play in aerosol particle chemical evolution. This information will improve the representativeness of process level models and laboratory experiments.
Much of what we know about atmospheric new particle formation (NPF) is based on ground-level...
Share