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The effect of temperature and relative humidity on secondary organic aerosol formation from ozonolysis of Δ3-carene

Thomsen, Ditte ; Iversen, Emil Mark ; Skønager, Jane Tygesen ; Luo, Yuanyuan ; Li, Linjie ; Roldin, Pontus LU ; Priestley, Michael ; Pedersen, Henrik B. ; Hallquist, Mattias and Ehn, Mikael , et al. (2023) In Environmental Science: Atmospheres
Abstract

This study investigates the effects of temperature and relative humidity (RH) on the formation of secondary organic aerosol (SOA) from Δ3-carene, a prevalent monoterpene in boreal forests. Dark ozonolysis experiments of 10 ppb Δ3-carene were conducted in the Aarhus University Research on Aerosol (AURA) atmospheric simulation chamber at temperatures of 0, 10, and 20 °C. Under dry conditions (RH < 2%), the SOA formation in terms of both particle number and mass concentration shows minimal temperature dependence. This is in contrast to previous findings at higher initial concentrations and suggests an effect of VOC loading for Δ3-carene. Interestingly, the mass fraction of key oxidation products... (More)

This study investigates the effects of temperature and relative humidity (RH) on the formation of secondary organic aerosol (SOA) from Δ3-carene, a prevalent monoterpene in boreal forests. Dark ozonolysis experiments of 10 ppb Δ3-carene were conducted in the Aarhus University Research on Aerosol (AURA) atmospheric simulation chamber at temperatures of 0, 10, and 20 °C. Under dry conditions (RH < 2%), the SOA formation in terms of both particle number and mass concentration shows minimal temperature dependence. This is in contrast to previous findings at higher initial concentrations and suggests an effect of VOC loading for Δ3-carene. Interestingly, the mass fraction of key oxidation products (cis-3-caric acid, cis-3-caronic acid) exhibit a temperature dependence suggesting continuous condensation at lower temperatures, while evaporation and further reactions over time become more favourable at higher temperatures. The oxygen-to-carbon ratios in the particle phase and the occurrence of highly oxygenated organic molecules (HOM) in the gas phase show modest increases with higher temperatures. Predictions from the Aerosol Dynamics and Gas- and Particle-Phase Chemistry Kinetic Multilayer Model (ADCHAM) agrees with the experimental results regarding both physical particle properties and aerosol composition considering the experimental uncertainties. At high RH (∼80%, 10 °C), a considerable increase in the particle nucleation rate and particle number concentration is observed compared to experiments under dry conditions. This is likely due to enhanced particle nucleation resulting from more stable cluster formation of water and inorganics at increased RH. However, RH does not affect the particle mass concentration.

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publication status
epub
subject
in
Environmental Science: Atmospheres
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85180086262
ISSN
2634-3606
DOI
10.1039/d3ea00128h
language
English
LU publication?
yes
id
4ac9644e-925b-4c26-8ff2-3c3e7cb9e9e1
date added to LUP
2024-01-10 16:24:06
date last changed
2024-01-10 16:25:40
@article{4ac9644e-925b-4c26-8ff2-3c3e7cb9e9e1,
  abstract     = {{<p>This study investigates the effects of temperature and relative humidity (RH) on the formation of secondary organic aerosol (SOA) from Δ<sup>3</sup>-carene, a prevalent monoterpene in boreal forests. Dark ozonolysis experiments of 10 ppb Δ<sup>3</sup>-carene were conducted in the Aarhus University Research on Aerosol (AURA) atmospheric simulation chamber at temperatures of 0, 10, and 20 °C. Under dry conditions (RH &lt; 2%), the SOA formation in terms of both particle number and mass concentration shows minimal temperature dependence. This is in contrast to previous findings at higher initial concentrations and suggests an effect of VOC loading for Δ<sup>3</sup>-carene. Interestingly, the mass fraction of key oxidation products (cis-3-caric acid, cis-3-caronic acid) exhibit a temperature dependence suggesting continuous condensation at lower temperatures, while evaporation and further reactions over time become more favourable at higher temperatures. The oxygen-to-carbon ratios in the particle phase and the occurrence of highly oxygenated organic molecules (HOM) in the gas phase show modest increases with higher temperatures. Predictions from the Aerosol Dynamics and Gas- and Particle-Phase Chemistry Kinetic Multilayer Model (ADCHAM) agrees with the experimental results regarding both physical particle properties and aerosol composition considering the experimental uncertainties. At high RH (∼80%, 10 °C), a considerable increase in the particle nucleation rate and particle number concentration is observed compared to experiments under dry conditions. This is likely due to enhanced particle nucleation resulting from more stable cluster formation of water and inorganics at increased RH. However, RH does not affect the particle mass concentration.</p>}},
  author       = {{Thomsen, Ditte and Iversen, Emil Mark and Skønager, Jane Tygesen and Luo, Yuanyuan and Li, Linjie and Roldin, Pontus and Priestley, Michael and Pedersen, Henrik B. and Hallquist, Mattias and Ehn, Mikael and Bilde, Merete and Glasius, Marianne}},
  issn         = {{2634-3606}},
  language     = {{eng}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Environmental Science: Atmospheres}},
  title        = {{The effect of temperature and relative humidity on secondary organic aerosol formation from ozonolysis of Δ<sup>3</sup>-carene}},
  url          = {{http://dx.doi.org/10.1039/d3ea00128h}},
  doi          = {{10.1039/d3ea00128h}},
  year         = {{2023}},
}