Identification

Title

Laboratory study on new particle formation from the reaction OH + SOâ‚‚: influence of experimental conditions, Hâ‚‚O vapour, NHâ‚ƒ and the amine tert-butylamine on the overall process

Abstract

Nucleation experiments starting from the reaction of OH radicals with SOâ‚‚ have been performed in the IfT-LFT flow tube under atmospheric conditions at 293Â±0.5 K for a relative humidity of 13-61%. The presence of different additives (Hâ‚‚, CO, 1,3,5-trimethylbenzene) for adjusting the OH radical concentration and resulting OH levels in the range (4-300) Ã—10âµ molecule cmâ»Â³ did not influence the nucleation process itself. The number of detected particles as well as the threshold Hâ‚‚SOâ‚„ concentration needed for nucleation was found to be strongly dependent on the counting efficiency of the used counting devices. High-sensitivity particle counters allowed the measurement of freshly nucleated particles with diameters down to about 1.5 nm. A parameterization of the experimental data was developed using power law equations for Hâ‚‚SOâ‚„ and Hâ‚‚O vapour. The exponent for Hâ‚‚SOâ‚„ from different measurement series was in the range of 1.7-2.1 being in good agreement with those arising from analysis of nucleation events in the atmosphere. For increasing relative humidity, an increase of the particle number was observed. The exponent for Hâ‚‚O vapour was found to be 3.1 representing an upper limit. Addition of 1.2Ã—10Â¹Â¹ molecule cmâ»Â³ or 1.2Ã—10Â¹Â² molecule cmâ»Â³ of NHâ‚ƒ (range of atmospheric NHâ‚ƒ peak concentrations) revealed that NHâ‚ƒ has a measureable, promoting effect on the nucleation rate under these conditions. The promoting effect was found to be more pronounced for relatively dry conditions, i.e. a rise of the particle number by 1-2 orders of magnitude at RH = 13% and only by a factor of 2-5 at RH = 47% (NHâ‚ƒ addition: 1.2Ã—10Â¹Â² molecule cmâ»Â³). Using the amine tert-butylamine instead of NHâ‚ƒ, the enhancing impact of the base for nucleation and particle growth appears to be stronger. Tert-butylamine addition of about 10Â¹â° molecule cmâ»Â³ at RH = 13% enhances particle formation by about two orders of magnitude, while for NHâ‚ƒ only a small or negligible effect on nucleation in this range of concentration appeared. This suggests that amines can strongly influence atmospheric Hâ‚‚SOâ‚„-Hâ‚‚O nucleation and are probably promising candidates for explaining existing discrepancies between theory and observations.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7n58mt0

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

2010-08-03T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

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