Elsevier

Journal of Aerosol Science

Volume 157, September 2021, 105808
Journal of Aerosol Science

A tutorial guide on new particle formation experiments using a laminar flow reactor

https://doi.org/10.1016/j.jaerosci.2021.105808Get rights and content
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Highlights

  • Design and operation of a low-cost flow reactor to study aerosol nucleation reactions.

  • Variable reaction times enable nucleation and initial particle growth to be observed.

  • Sample preparation and reactor operation to minimize system contamination.

Abstract

New particle formation (NPF) produces about 50% of the global cloud condensation nuclei in the troposphere. As such, NPF plays a crucial role in climate. Despite advancements in instrumentation capable of measuring freshly formed aerosol particles down to ~ 1 nm in diameter, the mechanisms behind NPF remain understudied due to the complex composition and chemistry of the atmosphere. Nucleation is the first step of NPF and involves gaseous precursors reacting to form stable clusters; consequently, it is essential to understand the reaction kinetics behind nucleation reactions. Controlled laboratory experiments have previously been used to examine these reactions, which can occur at extremely low reactant concentrations (i.e., parts per quadrillion level, 105 cm−3) or lower. Nucleation experiments require pristine conditions for the reactions to proceed without interference from unpredictable contaminants. Here, a low-cost flow reactor is presented that minimizes contamination and allows for nucleation kinetics to be observed. The layout and setup of an example reactor are presented with a brief discussion on how to operate the reactor to ensure cleanliness and repeatability. In addition, methods for quantifying nucleation reactants as well as analytical measurement techniques to adequately measure nucleation kinetics in this flow reactor system are described. This experimental protocol can be employed to characterize nucleation reactions that can ultimately be used to develop nucleation models important for predicting how aerosol particles influence climate.

Keywords

New particle formation (NPF)
Nucleation
Nucleation flow reactor

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