An isotopic analysis of ionising radiation as a source of sulphuric acid

Martin Andreas Bødker Enghoff; Nicolai Christian Bork; S. Hattori; Carl Meusinger; M. Nakagawa; Jens Olaf Pepke Pedersen; S. Danielache; Y. Ueno; Matthew Stanley Johnson; N. Yoshida; Henrik Svensmark

doi:10.5194/acp-12-5319-2012

An isotopic analysis of ionising radiation as a source of sulphuric acid

Martin Andreas Bødker Enghoff, Nicolai Christian Bork, S. Hattori, Carl Meusinger, M. Nakagawa, Jens Olaf Pepke Pedersen, S. Danielache, Y. Ueno, Matthew Stanley Johnson, N. Yoshida, Henrik Svensmark

Kemisk Institut

12 Citationer (Scopus)

Abstract

Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO ₂ through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in ³⁴S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO ₂ by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

Originalsprog	Engelsk
Tidsskrift	Atmospheric Chemistry and Physics Discussions
Vol/bind	12
Udgave nummer	12
Sider (fra-til)	5319-5327
Antal sider	9
ISSN	1680-7367
DOI	https://doi.org/10.5194/acp-12-5319-2012
Status	Udgivet - 2012

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10.5194/acp-12-5319-2012

Citationsformater

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title = "An isotopic analysis of ionising radiation as a source of sulphuric acid",

abstract = "Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO 2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO 2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.",

author = "Enghoff, {Martin Andreas B{\o}dker} and Bork, {Nicolai Christian} and S. Hattori and Carl Meusinger and M. Nakagawa and Pedersen, {Jens Olaf Pepke} and S. Danielache and Y. Ueno and Johnson, {Matthew Stanley} and N. Yoshida and Henrik Svensmark",

year = "2012",

doi = "10.5194/acp-12-5319-2012",

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T1 - An isotopic analysis of ionising radiation as a source of sulphuric acid

AU - Enghoff, Martin Andreas Bødker

AU - Bork, Nicolai Christian

AU - Hattori, S.

AU - Meusinger, Carl

AU - Nakagawa, M.

AU - Pedersen, Jens Olaf Pepke

AU - Danielache, S.

AU - Ueno, Y.

AU - Johnson, Matthew Stanley

AU - Yoshida, N.

AU - Svensmark, Henrik

PY - 2012

Y1 - 2012

N2 - Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO 2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO 2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

AB - Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO 2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO 2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

U2 - 10.5194/acp-12-5319-2012

DO - 10.5194/acp-12-5319-2012

M3 - Journal article

SN - 1680-7367

VL - 12

SP - 5319

EP - 5327

JO - Atmospheric Chemistry and Physics Discussions

JF - Atmospheric Chemistry and Physics Discussions

IS - 12

ER -

An isotopic analysis of ionising radiation as a source of sulphuric acid

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