Identification

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 ~1 to 3 nm geometric diameter, increasing from 5.5 ± 0.8 to 7.6 ± 0.6 nm h⁻¹ in Atlanta (13:00) and from 5.6 ± 2 to 27 ± 5 nm h⁻¹ in Boulder (13:00). The resulting growth rate enhancement Γ, 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 Γ had lower limits that approached ~1 at 1.2 nm geometric diameter in Atlanta and ~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.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7w37x02

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2012-04-12T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

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version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact