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

Abstract

This study presents measurements of size and time-resolved particle diameter growth rates for freshly nucleated 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) using a recently developed electrical mobility spectrometer with a diethylene glycol-based ultrafine condensation particle counter as the particle detector. One new particle formation (NPF) event from each campaign was analyzed in detail. 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 {approx}1 to 3 nm geometric diameter, increasing from 5.5 {+-} 0.8 to 7.6 {+-} 0.6 nm h{sup -1} in Atlanta (13:00) and from 5.6 {+-} 2 to 27 {+-} 5 nm h{sup -1} in Boulder (13:00). The resulting growth rate enhancement {Lambda}, defined as the ratio of the observed growth rate to the growth ratemore » due to the condensation of sulfuric acid only, was found to increase approximately linearly with size from {approx}1 to 3 nm geometric diameter. For the presented NPF events, values for {Lambda} had lower limits that approached {approx}1 at 1.2 nm geometric diameter in Atlanta and {approx}3 at 0.8 nm geometric diameter in Boulder, 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.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1048200
Report Number(s):
BNL-98145-2012-JA
Journal ID: ISSN 1680-7316; R&D Project: 2014-BNL-EE630EECA-Budg; KP1701000; TRN: US201216%%796
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Atmospheric Chemistry and Physics
Additional Journal Information:
Journal Volume: 12; Journal Issue: 7; Journal ID: ISSN 1680-7316
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AEROSOLS; DATA ANALYSIS; NUCLEI; PARTICLE SIZE; PROBABILITY; SPECTROMETERS; SULFURIC ACID; TIME DEPENDENCE

Citation Formats

Kuang, C, Chen, M, Zhao, J, Smith, J, McMurry, P H, and Wang, J. Size and time-resolved growth rate measurements of 1 to 5 nm freshly formed atmospheric nuclei. United States: N. p., 2012. Web. doi:10.5194/acp-12-3573-2012.
Kuang, C, Chen, M, Zhao, J, Smith, J, McMurry, P H, & Wang, J. Size and time-resolved growth rate measurements of 1 to 5 nm freshly formed atmospheric nuclei. United States. doi:10.5194/acp-12-3573-2012.
Kuang, C, Chen, M, Zhao, J, Smith, J, McMurry, P H, and Wang, J. Thu . "Size and time-resolved growth rate measurements of 1 to 5 nm freshly formed atmospheric nuclei". United States. doi:10.5194/acp-12-3573-2012.
@article{osti_1048200,
title = {Size and time-resolved growth rate measurements of 1 to 5 nm freshly formed atmospheric nuclei},
author = {Kuang, C and Chen, M and Zhao, J and Smith, J and McMurry, P H and Wang, J},
abstractNote = {This study presents measurements of size and time-resolved particle diameter growth rates for freshly nucleated 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) using a recently developed electrical mobility spectrometer with a diethylene glycol-based ultrafine condensation particle counter as the particle detector. One new particle formation (NPF) event from each campaign was analyzed in detail. 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 {approx}1 to 3 nm geometric diameter, increasing from 5.5 {+-} 0.8 to 7.6 {+-} 0.6 nm h{sup -1} in Atlanta (13:00) and from 5.6 {+-} 2 to 27 {+-} 5 nm h{sup -1} in Boulder (13:00). The resulting growth rate enhancement {Lambda}, 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 {approx}1 to 3 nm geometric diameter. For the presented NPF events, values for {Lambda} had lower limits that approached {approx}1 at 1.2 nm geometric diameter in Atlanta and {approx}3 at 0.8 nm geometric diameter in Boulder, 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.},
doi = {10.5194/acp-12-3573-2012},
journal = {Atmospheric Chemistry and Physics},
issn = {1680-7316},
number = 7,
volume = 12,
place = {United States},
year = {2012},
month = {4}
}