Effect of working fluid on sub-2 nm particle detection with a laminar flow ultrafine condensation particle counter

Kenjiro Iida, Mark R. Stolzenburg, Peter H McMurry

Research output: Contribution to journalArticlepeer-review

143 Scopus citations


The effect of working fluid on size-dependent activation efficiencies with the laminar flow ultrafine condensation particle counter described by Stolzenburg and McMurry (1991) was studied theoretically and experimentally. Criteria considered include tendency to avoid homogeneous nucleation within the condenser and toxicity. The working fluids that were identified have vapor pressures below that of butanol, so particles grow to smaller sizes and are more difficult to detect optically. Therefore we use a second, conventional CPC as a “booster” to grow particles to a detectable size. Experiments were performed to obtain the size- and material-dependent activation efficiencies for ethylene glycol, diethylene glycol, propylene glycol, oleic acid, and DOS. Using diethylene glycol and oleic acid, values of the 50% activation efficiency diameter, Dp50, for negatively charged particles generated by evaporating sodium chloride, ammonium sulfate, and silver were < 1.2 (< 0.8) nm, 1.4–1.5 (1.0–1.2) nm, and 1.9–2.0 (1.5) nm as mobility (mass) diameter, respectively. The stability of the UCPC for long-term operation using ethylene glycol and propylene glycol as working fluids was tested by monitoring the instrument's response to silver particles having size near Dp50 in an air stream at 40–45% relative humidity. The performance was steady (±3%) for several days indicating the instrument performs stably during unattended operation for realistic atmospheric sampling conditions.

Original languageEnglish (US)
Pages (from-to)81-96
Number of pages16
JournalAerosol Science and Technology
Issue number1
StatePublished - Jan 1 2009

Bibliographical note

Funding Information:
This work was supported by NSF Award Number ATM-0506674. We greatly appreciate the insightful comments and suggestions of Prof. Fernandez de la Mora at Yale University and Prof. Okuyama at Hiroshima University, which significantly impacted this work.


Dive into the research topics of 'Effect of working fluid on sub-2 nm particle detection with a laminar flow ultrafine condensation particle counter'. Together they form a unique fingerprint.

Cite this