05 Sep 2023
 | 05 Sep 2023
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Variation in chemical composition and volatility of oxygenated organic aerosol in different rural, urban, and remote environments

Wei Huang, Cheng Wu, Linyu Gao, Yvette Gramlich, Sophie L. Haslett, Joel Thornton, Felipe D. Lopez-Hilfiker, Ben H. Lee, Junwei Song, Harald Saathoff, Xiaoli Shen, Ramakrishna Ramisetty, Sachchida N. Tripathi, Dilip Ganguly, Feng Jiang, Magdalena Vallon, Siegfried Schobesberger, Taina Yli-Juuti, and Claudia Mohr

Abstract. The apparent volatility of atmospheric organic aerosol (OA) particles is determined by their chemical composition and environmental conditions (e.g., ambient temperature). A quantitative, experimental assessment of volatility and the respective importance of these two factors remains challenging, especially in ambient measurements. We present molecular composition and volatility of oxygenated OA (OOA) particles in different rural, urban, and remote environments across the globe (including Chacaltaya, Bolivia; Alabama, U.S.; Hyytiälä, Finland; Stuttgart and Karlsruhe, Germany; and Delhi, India) based on deployments of a filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-CIMS). We find on average larger carbon numbers (nC) and lower oxygen-to-carbon (O:C) ratios at the urban sites (nC: 9.8±0.7; O:C: 0.76±0.03; average ± 1 standard deviation), compared to the rural (nC: 8.8±0.6; O:C: 0.80±0.05) and remote mountain stations (nC: 8.1±0.8; O:C: 0.91±0.07), indicative of different emission sources and chemistry. Compounds containing only carbon, hydrogen, and oxygen atoms (CHO) contribute highest to the total OOA mass at the rural sites (79.9±5.2 %), in accordance with their proximity to forested areas (66.2±5.5 % at the mountain sites and 72.6±4.3 % at the urban sites). The largest contribution of nitrogen-containing compounds (CHON) are found at the urban stations (27.1±4.3 %), consistent with their higher NOx levels. Besides, we parametrize OOA volatility (saturation mass concentrations, Csat) using molecular composition information and compare it with the bulk apparent volatility derived from thermal desorption of the OOA particles within the FIGAERO. We find differences in Csat values of up to ~3 orders of magnitude, and variation in thermal desorption profiles (thermograms) across different locations and systems. From our study, we draw the general conclusion that environmental conditions (e.g., ambient temperature) do not directly affect OOA apparent volatility, but rather indirectly by influencing the sources and chemistry of the environment and thus the chemical composition. The comprehensive global dataset provides results that show the complex thermodynamics and chemistry of OOA and their changes during its lifetime in the atmosphere, and that generally the chemical description of OOA suffices to predict its apparent volatility, at least qualitatively. Our study thus provides new insights that will help guide choices of e.g. descriptions of OOA volatility in different model frameworks which has been previously simplified due to challenges to measure and represent it in models.

Wei Huang et al.

Status: open (until 17 Oct 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1821', Anonymous Referee #1, 02 Oct 2023 reply
  • RC2: 'Comment on egusphere-2023-1821', Anonymous Referee #2, 04 Oct 2023 reply

Wei Huang et al.


Total article views: 343 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
237 94 12 343 20 6 9
  • HTML: 237
  • PDF: 94
  • XML: 12
  • Total: 343
  • Supplement: 20
  • BibTeX: 6
  • EndNote: 9
Views and downloads (calculated since 05 Sep 2023)
Cumulative views and downloads (calculated since 05 Sep 2023)

Viewed (geographical distribution)

Total article views: 337 (including HTML, PDF, and XML) Thereof 337 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 04 Oct 2023
Short summary
We present distinct molecular composition and volatility of oxygenated organic aerosol particles in different rural, urban, and remote environments across the globe. We did a comprehensive investigation of the relationship between chemical composition and volatility of oxygenated organic aerosol particles across different systems and environments. This study provides implications for volatility descriptions of oxygenated organic aerosol particles in different model frameworks.