Volatility of Springtime ambient organic aerosol derived with thermodenuder aerosol mass spectrometry in Seoul, Korea

The volatilities of ambient organic aerosol (OA) components are important to forecasting OA formation with models. However, providing the OA volatility distribution inputs for models is challenging, and models often rely on measurements from chamber experiments. We measured the volatility of submicron ambient OA in Seoul during May/June of 2019 by connecting a thermodenuder to an Aerodyne Time-of-Flight Aerosol Mass Spectrometer (AMS). We calculated a volatility basis set (VBS) of the organic aerosol with a thermodenuder mass transfer model and data from the thermodenuder set to various temperatures (30-200 degrees C). We found a large discrepancy between the measured ambient VBS and a reference VBS used in air quality models, with the ambient organics being less volatile. The results suggest that a modeling study that tries to account for this discrepancy may be needed to identify the impact it has on modeling outcomes. Chamber experiments aiming to determine VBSs for specific chemical systems should address limitations caused by wall losses and incomplete modeling parameters.

Automated summary

This study measured the volatility of submicron ambient organic aerosol in Seoul in 2019 and compared it with reference data used in air quality models, revealing a significant discrepancy between the two. The results suggest the need for modeling studies to investigate the impact of this discrepancy on model outcomes, and highlight the importance of addressing limitations caused by wall losses and incomplete modeling parameters in chamber experiments aiming to determine volatility basis sets.