Size and time-resolved growth rate measurements of 1 to 5 nm freshly formed atmospheric nuclei

By C. Kuang, Ming Chen, Jun Zhao, J. Smith, P. Mcmurry, Jian Wang. 2012

144 citations recorded by the source corpus.

This study presents measurements of size and time-resolved particle diameter growth rates for freshly nu- cleated particles down to 1 nm geometric diameter. Novel data analysis methods were developed, de-coupling for the first time the size and time-dependence of particle growth rates by fitting the aerosol general dynamic equation to size distributions obtained at an instant in time. Size distributions of freshly nucleated total aerosol (neutral and charged) were measured during two intensive measurement campaigns in different environments (Atlanta, GA and Boulder, CO) us- ing a recently developed electrical mobility spectrometer with a diethylene glycol-based ultrafine condensation parti- cle counter as the particle detector. One new particle forma- tion (NPF) event from each campaign was analyzed in de- tail. At a given instant in time during the NPF event, size- resolved growth rates were obtained directly from measured size distributions and were found to increase approximately linearly with particle size from 1 to 3 nm geometric di- ameter, increasing from 5.5± 0.8 to 7.6± 0.6 nm h 1 in At- lanta (13:00) and from 5.6± 2 to 27± 5 nm h 1 in Boulder (13:00). The resulting growth rate enhancement0, defined as the ratio of the observed growth rate to the growth rate due to the condensation of sulfuric acid only, was found to increase approximately linearly with size from 1 to 3 nm geometric diameter. For the presented NPF events, values for 0 had lower limits that approached 1 at 1.2 nm geometric diame- ter in Atlanta and 3 at 0.8 nm geometric diameter in Boul- der, and had upper limits that reached 8.3 at 4.1 nm geometric diameter in Atlanta and 25 at 2.7 nm geometric diameter in Boulder. Nucleated particle survival probability calculations comparing the effects of constant and size-dependent growth indicate that neglecting the strong dependence of growth rate on size from 1 to 3 nm observed in this study could lead to a significant overestimation of CCN survival probability.

Subfields: Atmospheric Science, Global and Planetary Change, Health, Toxicology and Mutagenesis

View Paper: https://www.semanticscholar.org/paper/731ffbd9505beaf13e4090eb15294b098d9d538d

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Citations in the corpus

Cloud condensation nuclei production associated with atmospheric nucleation: a synthesis based on existing literature and new results (2012, background): “While in theory these processes could either enhance or suppress the growth of very small nuclei, the few existing field measurements suggest that the sub-3 nm nuclei usually grow somewhat slower than larger nuclei (Hirsikko et al., 2005; Manninen et al., 2010; Kuang et al., 2012).”
Methods for determining particle size distribution and growth rates between 1 and 3 nm using the Particle Size Magnifier (2014, methodology): “Iida et al. (2009) showed that diethylene glycol (DEG) has preferable characteristics for activating small particles, and several Condensation Particle Counter (CPC) applications using DEG as condensing fluid have been developed (Jiang et al. 2011, Vanhanen et al. 2011, Kuang et al. 2012a).”