The effect of temperature and relative humidity on secondary organic aerosol formation from ozonolysis of Δ3-carene
(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.
(Less)
- author
- organization
- publishing date
- 2023
- type
- Contribution to journal
- 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 < 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}}, }