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Collection efficiency of α-pinene secondary organic aerosol particles explored via light scattering single particle aerosol mass spectrometry.
- Source :
-
Atmospheric Measurement Techniques Discussions . 2016, p1-29. 29p. - Publication Year :
- 2016
-
Abstract
- We investigated the collection efficiency and effective ionization efficiency for secondary organic aerosol (SOA) particles made from α-pinene + O3 using the single-particle capabilities of the Aerosol Mass Spectrometer (AMS). The mean count-based collection efficiency (CEp) for SOA across these experiments is 0.30 (±0.04 S.D.), ranging from 0.25 to 0.40. The mean mass-based collection efficiency (CEm) is 0.49 (0.07 S.D.). This sub-unit collection efficiency and delayed vaporization is attributable to particle bounce in the vaporization region. Using the coupled optical and chemical detection of the light scattering single-particle (LSSP) module 5 of the AMS, we provide clear evidence that "delayed vaporization" is somewhat of a misnomer for these particles: SOA particles that appear within the chopper window do not vaporize at a slow rate; rather, they flash-vaporize, but often not on the initial impact with the vaporizer, and instead upon a subsequent impact with a hot surface in the vaporization region. We also find that the effective ionization efficiency (defined as ions per particle, IPP) decreases with delayed arrival time. CEp is not a function of particle size (for the mobility diameter range investigated, 170-460nm), but we did see a decrease in CEp with thermodenuder temperature, implying that oxidation state and/or volatility can affect CEp for SOA. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18678610
- Database :
- Academic Search Index
- Journal :
- Atmospheric Measurement Techniques Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 118916281
- Full Text :
- https://doi.org/10.5194/amt-2016-271