Preprints
https://doi.org/10.5194/amt-2020-443
https://doi.org/10.5194/amt-2020-443

  03 Dec 2020

03 Dec 2020

Review status: a revised version of this preprint was accepted for the journal AMT and is expected to appear here in due course.

Captive Aerosol Growth and Evolution (CAGE) chamber system to investigate particle growth due to secondary aerosol formation

Candice L. Sirmollo1,2, Don R. Collins1,2, Jordan M. McCormick3, Cassandra F. Milan3, Matthew H. Erickson4, James H. Flynn4, Rebecca J. Sheesley5, Sascha Usenko5, Henry W. Wallace6, Alexander A. T. Bui6, Robert J. Griffin6, Matthew Tezak7, Sean M. Kinahan7,8, and Joshua L. Santarpia9 Candice L. Sirmollo et al.
  • 1Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521 USA
  • 2College of Engineering, Center for Environmental Research and Technology (CE-CERT), University of California Riverside, Riverside, California 92507 USA
  • 3Department of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843 USA
  • 4Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204 USA
  • 5Department of Environmental Science, Baylor University, Waco, Texas 76798 USA
  • 6Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005 USA
  • 7Sandia National Laboratory, Albuquerque, New Mexico 87123 USA
  • 8Biodefense and Health Security, University of Nebraska Medical Center, Omaha, Nebraska 68198 USA
  • 9Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198 USA

Abstract. Environmental chambers are a commonly used tool for studying the production and processing of aerosols in the atmosphere. Most are located indoors and most are filled with air having prescribed concentrations of a small number of reactive gas species. Here we describe portable chambers that are used outdoors and filled with mostly ambient air. Each all-Teflon® 1-m3 Captive Aerosol Growth and Evolution (CAGE) chamber has a cylindrical shape that rotates along its horizontal axis. A gas-permeable membrane allows exchange of gas-phase species between the chamber and surrounding ambient air with a mixing time constant of approximately 0.5 h. The membrane non-permeable to particles, and those that are injected into or nucleate in the chamber are exposed to the ambient-mirroring environment until being sampled or lost to the walls. The chamber and surrounding enclosure are made of materials that are highly transmitting across the solar ultraviolet and visible wavelength spectrum. Steps taken in the design and operation of the chambers to maximize particle lifetime resulted in averages of 6.0 h, 8.2 h, and 3.9 h for ~0.06 µm, ~0.3 µm, and ~2.5 µm diameter particles, respectively. Two of the newly developed CAGE chamber systems were characterized using data acquired during a 2-month field study in 2016 in a forested area north of Houston, TX, U.S. Estimations of measured and unmeasured gas-phase species and of secondary aerosol production in the chambers were made using a zero-dimensional model that treats chemical reactions in the chamber and the continuous exchange of gases with the surrounding air. Concentrations of NO, NO2, NOy, O3, and several organic compounds measured in the chamber were found to be in close agreement with those calculated from the model, with all having near 1.0 best fit slopes and high r2 values. The growth rates of particles in the chambers were quantified by tracking the narrow modes that resulted from injection of monodisperse particles and from occasional new particle formation bursts. Size distributions in the two chambers were measured intermittently 24 h day−1. A bimodal diel particle growth rate pattern was observed, with maxima of about 6 nm h−1 in the late morning and early evening and minima of less than 1 nm h−1 shortly before sunrise and sunset. A pattern change was observed for hourly averaged growth rates between late summer and early fall.

Candice L. Sirmollo et al.

 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Candice L. Sirmollo et al.

Candice L. Sirmollo et al.

Viewed

Total article views: 260 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
182 75 3 260 28 5 5
  • HTML: 182
  • PDF: 75
  • XML: 3
  • Total: 260
  • Supplement: 28
  • BibTeX: 5
  • EndNote: 5
Views and downloads (calculated since 03 Dec 2020)
Cumulative views and downloads (calculated since 03 Dec 2020)

Viewed (geographical distribution)

Total article views: 213 (including HTML, PDF, and XML) Thereof 212 with geography defined and 1 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 15 Apr 2021
Download