Abstract
Measurements of aerosol particles and clusters smaller than 3 nm in diameter are performed by many groups in order to detect recently formed or emitted nanoparticles and for studying the formation and early growth processes of aerosol particles. The Airmodus nano-Condensation Nucleus Counter (nCNC), consisting of a Particle Size Magnifier (PSM) and a Condensation Particle Counter (CPC) is a versatile tool to detect aerosol particles and clusters as small as ca. 1 nm in mobility diameter. It offers several different operation modes: fixed mode to measure the total particle number concentration with a fixed, but adjustable lower cut-off size and stepping and scanning modes for retrieving size-resolved information of ca. 1–4 nm particles. The size analysis is based on changing the supersaturation of the working fluid (diethylene glycol) inside the instrument, which changes the lowest detectable size. Here we present a standard operating procedure (SOP) for setting up, calibrating and operating the instrument for atmospheric field measurements. We will also present recommendations for data monitoring and analysis, and discuss some of the uncertainties related to the measurements. This procedure is the first step in harmonizing the use of the PSM/nCNC for atmospheric field measurements of sub-3 nm clusters and particles.
Highlights
Methods for determining nucleation and growth rates using Particle Size Magnifier (PSM) data have been defined in several articles (Dada et al, 2020; Kulmala et al, 2012; Lehtipalo et al, 2014). The aim of this protocol is to describe the best practices for operating the PSM/nano-Condensation Nucleus Counter (nCNC) in field conditions and to unify the mea surement procedures used by different groups, especially within the ACTRIS (Aerosols, Clouds and Trace gases Research Infrastruc ture) community, for achieving comparable, high-quality observations of sub-3 nm particles
The con centration calibration is done by comparing the concentration measurement of the test condensation particle counter (CPC) against the concentration measured with a reference CPC or faraday cup electrometer (FCE) for size-selected aerosol particles
Measurement of nanoscale aerosol particles is challenging especially in the sub-3 nm size range due to their low charging prob ability and high diffusional losses, which limit the applicability of electrical measurement techniques
Summary
The Airmodus Particle Size Magnifier (PSM) was developed originally at the University of Helsinki to measure particles smaller. Methods for determining nucleation and growth rates using PSM data have been defined in several articles (Dada et al, 2020; Kulmala et al, 2012; Lehtipalo et al, 2014) The aim of this protocol is to describe the best practices for operating the PSM/nCNC in field conditions and to unify the mea surement procedures used by different groups, especially within the ACTRIS (Aerosols, Clouds and Trace gases Research Infrastruc ture) community, for achieving comparable, high-quality observations of sub-3 nm particles. G. due to varying external conditions, which the users should be aware of This protocol is based on almost 10 years of experience working with the Particle Size Magnifier at the University of Helsinki, as well as discussions between the users and instrument manufacturer. The procedures presented here are related to the current PSM/nCNC versions in use (A09/A11) and should be updated or revised upon significant technical development of the instrumentation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
