Emission of volatile organic compounds and production of secondary organic aerosol from stir-frying spices

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Tengyu Liu
  • Qianyun Liu
  • Zijun Li
  • Lei Huo
  • ManNin Chan
  • Zhen Zhou

Related Research Unit(s)

Detail(s)

Original languageEnglish
Pages (from-to)1614-1621
Journal / PublicationScience of the Total Environment
Volume599-600
Online published19 May 2017
Publication statusPublished - 1 Dec 2017

Abstract

Cooking is an important source of volatile organic compounds (VOCs) and a potential source of secondary organic aerosol (SOA) both indoors and outdoors. In this study, VOC emissions from heating corn oil and stir-frying spices (i.e. garlic, ginger, myrcia and zanthoxylum piperitum (Sichuan pepper)) were characterized using an on-line membrane inlet vacuum ultraviolet single-photon ionization time-of-flight mass spectrometer (VUV-SPI-TOFMS). VOC emissions from heating corn oil were dominated by aldehydes, which were enhanced by factors of one order of magnitude when stir-frying spices. Stir-frying any of the spices studied generated large amounts of methylpyrrole (m/z 81). In addition, stir-frying garlic produced abundant dihydrohydroxymaltol (m/z 144) and diallyldisulfide (DADS) (m/z 146), while stir-frying ginger, myrcia and zanthoxylum piperitum produced abundant monoterpenes (m/z 136) and terpenoids (m/z 152, 154). SOA formed from emissions of stir-frying spices through reactions with excess ozone in a flow reactor as well as primary organic aerosol (POA) emissions were characterized using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS). Stir-frying garlic and ginger generated similar POA concentrations to those from heating corn oil while stir-frying myrcia and zanthoxylum piperitum generated double the amount of emissions. No SOA was observed from stir-frying garlic and ginger. The rates of SOA production from stir-frying myrcia and zanthoxylum piperitum were 1.8 μg min− 1 gspice − 1 and 8.7 μg min− 1 gspice − 1, equivalent to 13.4% and 53.1% of their own POA emission rates, respectively. Therefore, the contribution of stir-frying spices to ambient organic aerosol levels is likely dominated by POA. The rates of total terpene emission from stir-frying myrcia and zanthoxylum piperitum were estimated to be 5.1 μg min− 1 gspice − 1 and 24.9 μg min− 1 gspice − 1, respectively. Our results suggest that stir-frying spices could be an important source of terpenes in indoor environments in Hong Kong, at least during cooking.

Research Area(s)

  • Cooking emissions, Secondary organic aerosol, Spices, Terpenes, Volatile organic compounds

Citation Format(s)

Emission of volatile organic compounds and production of secondary organic aerosol from stir-frying spices. / Liu, Tengyu; Liu, Qianyun; Li, Zijun; Huo, Lei; Chan, ManNin; Li, Xue; Zhou, Zhen; Chan, Chak K.

In: Science of the Total Environment, Vol. 599-600, 01.12.2017, p. 1614-1621.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review