Indoor ozone/human chemistry and ventilation strategies

Christian Mark Salvador, Gabriel Bekö, Charles J. Weschler, Glenn Morrison, Michael Le Breton, Mattias Hallquist, Lars Ekberg, Sarka Langer*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously-ventilated climate chamber at two air exchange rates (1 h-1 and 3 h-1 ) and two initial ozone mixing ratios (30 ppb and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A Time-of-Flight-Chemical Ionization-Mass-Spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation. This article is protected by copyright. 
Original languageEnglish
JournalIndoor Air
Volume29
Issue number6
Pages (from-to)913-925
ISSN0905-6947
DOIs
Publication statusPublished - 2019

Keywords

  • Indoor environment
  • ToF-CIMS
  • Air exchange rate
  • Oxygenated volatile organic compounds
  • Ozone
  • Squalene

Cite this

Salvador, C. M., Bekö, G., Weschler, C. J., Morrison, G., Le Breton, M., Hallquist, M., ... Langer, S. (2019). Indoor ozone/human chemistry and ventilation strategies. Indoor Air, 29(6), 913-925. https://doi.org/10.1111/ina.12594
Salvador, Christian Mark ; Bekö, Gabriel ; Weschler, Charles J. ; Morrison, Glenn ; Le Breton, Michael ; Hallquist, Mattias ; Ekberg, Lars ; Langer, Sarka. / Indoor ozone/human chemistry and ventilation strategies. In: Indoor Air. 2019 ; Vol. 29, No. 6. pp. 913-925.
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author = "Salvador, {Christian Mark} and Gabriel Bek{\"o} and Weschler, {Charles J.} and Glenn Morrison and {Le Breton}, Michael and Mattias Hallquist and Lars Ekberg and Sarka Langer",
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Salvador, CM, Bekö, G, Weschler, CJ, Morrison, G, Le Breton, M, Hallquist, M, Ekberg, L & Langer, S 2019, 'Indoor ozone/human chemistry and ventilation strategies', Indoor Air, vol. 29, no. 6, pp. 913-925. https://doi.org/10.1111/ina.12594

Indoor ozone/human chemistry and ventilation strategies. / Salvador, Christian Mark; Bekö, Gabriel; Weschler, Charles J.; Morrison, Glenn; Le Breton, Michael; Hallquist, Mattias; Ekberg, Lars; Langer, Sarka.

In: Indoor Air, Vol. 29, No. 6, 2019, p. 913-925.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Indoor ozone/human chemistry and ventilation strategies

AU - Salvador, Christian Mark

AU - Bekö, Gabriel

AU - Weschler, Charles J.

AU - Morrison, Glenn

AU - Le Breton, Michael

AU - Hallquist, Mattias

AU - Ekberg, Lars

AU - Langer, Sarka

PY - 2019

Y1 - 2019

N2 - This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously-ventilated climate chamber at two air exchange rates (1 h-1 and 3 h-1 ) and two initial ozone mixing ratios (30 ppb and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A Time-of-Flight-Chemical Ionization-Mass-Spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation. This article is protected by copyright. 

AB - This study aimed to better understand and quantify the influence of ventilation strategies on occupant-related indoor air chemistry. The oxidation of human skin oil constituents was studied in a continuously-ventilated climate chamber at two air exchange rates (1 h-1 and 3 h-1 ) and two initial ozone mixing ratios (30 ppb and 60 ppb). Additional measurements were performed to investigate the effect of intermittent ventilation ("off" followed by "on"). Soiled t-shirts were used to simulate the presence of occupants. A Time-of-Flight-Chemical Ionization-Mass-Spectrometer (ToF-CIMS) in positive mode using protonated water clusters was used to measure the oxygenated reaction products geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA). The measurement data were used in a series of mass balance models accounting for formation and removal processes. Reactions of ozone with squalene occurring on the surface of the t-shirts are mass transport limited; ventilation rate has only a small effect on this surface chemistry. Ozone-squalene reactions on the shirts produced gas-phase geranyl acetone, which was subsequently removed almost equally by ventilation and further reaction with ozone. About 70% of gas-phase 6-MHO was produced in surface reactions on the t-shirts, the remainder in secondary gas-phase reactions of ozone with geranyl acetone. 6-MHO was primarily removed by ventilation, while further reaction with ozone was responsible for about a third of its removal. 4-OPA was formed primarily on the surfaces of the shirts (~60%); gas-phase reactions of ozone with geranyl acetone and 6-MHO accounted for ~30% and ~10%, respectively. 4-OPA was removed entirely by ventilation. The results from the intermittent ventilation scenarios showed delayed formation of the reaction products and lower product concentrations compared to continuous ventilation. This article is protected by copyright. 

KW - Indoor environment

KW - ToF-CIMS

KW - Air exchange rate

KW - Oxygenated volatile organic compounds

KW - Ozone

KW - Squalene

U2 - 10.1111/ina.12594

DO - 10.1111/ina.12594

M3 - Journal article

VL - 29

SP - 913

EP - 925

JO - Indoor Air

JF - Indoor Air

SN - 0905-6947

IS - 6

ER -

Salvador CM, Bekö G, Weschler CJ, Morrison G, Le Breton M, Hallquist M et al. Indoor ozone/human chemistry and ventilation strategies. Indoor Air. 2019;29(6):913-925. https://doi.org/10.1111/ina.12594