Gas-particle partitioning of semivolatile organic compounds when wildfire smoke comes to town

TY - JOUR

T1 - Gas-particle partitioning of semivolatile organic compounds when wildfire smoke comes to town

AU - Liang, Yutong

AU - Wernis, Rebecca A.

AU - Kristensen, Kasper

AU - Kreisberg, Nathan M.

AU - Croteau, Philip L.

AU - Herndon, Scott C.

AU - Chan, Arthur W.H.

AU - Ng, Nga L.

AU - Goldstein, Allen H.

N1 - Publisher Copyright: © 2023 Yutong Liang et al.

PY - 2023/10

Y1 - 2023/10

N2 - Wildfires have become an increasingly important source of organic gases and particulate matter in the western USA. A large fraction of organic particulate matter emitted in wildfires is semivolatile, and the oxidation of organic gases in smoke can form lower-volatility products that then condense on smoke particulates. In this research, we measured the gas- and particle-phase concentrations of semivolatile organic compounds (SVOCs) during the 2017 northern California wildfires in a downwind urban area, using semivolatile thermal desorption aerosol gas chromatography (SV-TAG), and measured SVOCs in a rural site affected by biomass burning using cTAG (comprehensive thermal desorption aerosol gas chromatography mass spectrometry) in Idaho in 2018. Commonly used biomass burning markers such as levoglucosan, mannosan, and nitrocatechols were found to stay predominantly in the particle phase, even when the ambient organic aerosol (OA) was relatively low. The phase partitioning of SVOCs is observed to be dependent on their saturation vapor pressure, while the equilibrium absorption model underpredicts the particle-phase fraction of most of the compounds measured. Wildfire organic aerosol enhanced the condensation of polar compounds into the particle phase but not some nonpolar compounds, such as polycyclic aromatic hydrocarbons.

AB - Wildfires have become an increasingly important source of organic gases and particulate matter in the western USA. A large fraction of organic particulate matter emitted in wildfires is semivolatile, and the oxidation of organic gases in smoke can form lower-volatility products that then condense on smoke particulates. In this research, we measured the gas- and particle-phase concentrations of semivolatile organic compounds (SVOCs) during the 2017 northern California wildfires in a downwind urban area, using semivolatile thermal desorption aerosol gas chromatography (SV-TAG), and measured SVOCs in a rural site affected by biomass burning using cTAG (comprehensive thermal desorption aerosol gas chromatography mass spectrometry) in Idaho in 2018. Commonly used biomass burning markers such as levoglucosan, mannosan, and nitrocatechols were found to stay predominantly in the particle phase, even when the ambient organic aerosol (OA) was relatively low. The phase partitioning of SVOCs is observed to be dependent on their saturation vapor pressure, while the equilibrium absorption model underpredicts the particle-phase fraction of most of the compounds measured. Wildfire organic aerosol enhanced the condensation of polar compounds into the particle phase but not some nonpolar compounds, such as polycyclic aromatic hydrocarbons.

UR - http://www.scopus.com/inward/record.url?scp=85177767927&partnerID=8YFLogxK

U2 - 10.5194/acp-23-12441-2023

DO - 10.5194/acp-23-12441-2023

M3 - Journal article

AN - SCOPUS:85177767927

SN - 1680-7316

VL - 23

SP - 12441

EP - 12454

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

IS - 19

ER -