Simultaneous dry and ambient measurements of aerosol size distributions at the Jungfraujoch

Type
01A - Journal article
Editors
Editor (Corporation)
Supervisor
Parent work
Tellus B: Chemical and Physical Meteorology
Special issue
DOI of the original publication
Link
Series
Series number
Volume
55
Issue / Number
3
Pages / Duration
808-819
Patent number
Publisher / Publishing institution
Stockholm University Press
Place of publication / Event location
Stockholm
Edition
Version
Programming language
Assignee
Practice partner / Client
Abstract
In a field campaign at the high-alpine site Jungfraujoch (JFJ, 3580 m asl), in-situ aerosol size distributions were measured simultaneously outdoor at ambient conditions (temperature T < -5 °C) and indoor at dry conditions (T ≈ 25 °C and relative humidity RH < 10%) by means of two scanning mobility particle sizers (SMPS). In addition, measurements of hygroscopic growth factors were performed with a hygroscopicity tandem differential mobility analyzer (H-TDMA). The measured growth factors, being a monotonic function of the relative humidity (RH), were fitted with a modified Köhler model. A comparison between dry and ambient size distributions shows two main features: First, the dry total number concentration is often considerably smaller (on average 28%) than the ambient total number concentration, and is most likely due to the evaporation of volatile material at the higher temperature. These particle losses mainly concern small particles (dry diameter D ≲ 100 nm), and therefore have only a minimal affect on the surface and volume concentrations. A slight correlation between ambient RH and the magnitude of particle loss was observed, but it was not possible to establish an empirical model for a quantification. Second, the dry number size distribution is shifted towards smaller particles, reflecting the hygroscopic behavior of the aerosols. To link the ambient and the dry size distributions we modeled this shift using the H-TDMA measurements and a modified Köhler model. The corrected dry surface and volume concentrations are in good agreement with the ambient measurements for the whole RH range, but the correction works best for RH < 80%. The results indicate that size distribution data measured at indoor conditions (i.e. dry and warm) may be successfully corrected to reflect ambient conditions, which are relevant for determining the impact of aerosol on climate.
Keywords
Project
Event
Exhibition start date
Exhibition end date
Conference start date
Conference end date
Date of the last check
ISBN
ISSN
1600-0889
0280-6509
Language
English
Created during FHNW affiliation
No
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the complete publication
Open access category
Closed
License
Citation
Nessler, R., Bukowiecki, N., Henning, S., Weingartner, E., Calpini, B., & Baltensperger, U. (2003). Simultaneous dry and ambient measurements of aerosol size distributions at the Jungfraujoch. Tellus B: Chemical and Physical Meteorology, 55(3), 808–819. https://doi.org/10.3402/tellusb.v55i3.16371