Preprints
https://doi.org/10.5194/egusphere-2023-2657
https://doi.org/10.5194/egusphere-2023-2657
27 Nov 2023
 | 27 Nov 2023

Suppressed atmospheric chemical aging of cooking organic aerosol particles in wintertime conditions

Wenli Liu, Longkun He, Yingjun Liu, Keren Liao, Qi Chen, and Mikinori Kuwata

Abstract. Cooking organic aerosol (COA) is one of the major constituents of particulate matter in urban areas. COA is oxidized by atmospheric oxidants such as ozone, changing its physical, chemical and toxicological properties. However, atmospheric chemical lifetimes of COA and its tracers such as oleic acid are typically longer than that have been estimated by laboratory studies. We tackled the issue by considering temperature. Namely, we hypothesize that increased viscosity of COA at ambient temperature accounts for its prolonged atmospheric chemical lifetimes in wintertime. Laboratory generated COA particles from cooking oil were exposed to ozone in an aerosol flow tube reactor for the temperature range of -20 °C ~ 35 °C. The pseudo-second order chemical reaction rate constants (k2) decreased by orders of magnitude for lower temperatures. The temperature dependence of k2 was fit well by considering diffusion-limited chemical reaction mechanism, suggesting that reduced viscosity was responsible for the decrease in chemical reactivity. In combination with the observed global surface temperature, the atmospheric chemical lifetimes of COA were estimated to be much longer in wintertime (>1 hour) than that in summertime (a few minutes) for temperate and boreal regions. Our present study demonstrates that the oxidation lifetimes of COA particles will need to be parameterized as a function of temperature in the future for estimating environmental impacts and fates of this category of particulate matter.

Wenli Liu, Longkun He, Yingjun Liu, Keren Liao, Qi Chen, and Mikinori Kuwata

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2657', Anonymous Referee #1, 11 Dec 2023
  • RC2: 'Comment on egusphere-2023-2657', Anonymous Referee #2, 12 Dec 2023
Wenli Liu, Longkun He, Yingjun Liu, Keren Liao, Qi Chen, and Mikinori Kuwata
Wenli Liu, Longkun He, Yingjun Liu, Keren Liao, Qi Chen, and Mikinori Kuwata

Viewed

Total article views: 193 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
142 43 8 193 21 2 6
  • HTML: 142
  • PDF: 43
  • XML: 8
  • Total: 193
  • Supplement: 21
  • BibTeX: 2
  • EndNote: 6
Views and downloads (calculated since 27 Nov 2023)
Cumulative views and downloads (calculated since 27 Nov 2023)

Viewed (geographical distribution)

Total article views: 188 (including HTML, PDF, and XML) Thereof 188 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 29 Feb 2024
Download
Short summary
Cooking is one of the major particle sources in urban areas. Previous laboratory studies demonstrated the chemical lifetimes of cooking organic aerosols were much shorter (~minutes) than the values reported by field observations (~hours). We conducted laboratory experiments to resolve the discrepancy by considering suppressed reactivity under low temperature. The parameterized k2-T relationships and observed surface temperature data were used to estimate the chemical lifetimes of COA particles.