Comment on acp-2021-262

Abstract

In the study by Liu et al. simultaneous gas and particle phase measurements at a surface and a mountain site in the Beijing area were performed and analyzed. The effects of the dilution of pollutants uplifted from the surface to the mountain site during periods with a well-mixed boundary layer was investigated. Difference in the characteristics of the semi volatile organic and inorganic fractions compared to the low volatile organic and inorganic fraction in the aerosols was observed. The results show a significant decrease in the more volatile fraction with a simultaneous increase in the low volatile fraction during period when convective mixing was strongest. The measurements provide direct field observations on an important aspect of the potential evaporation of semi-volatile compounds from the aerosol phase due to the dilution of the gas phase concentration. I recommend the study for publication after the following comments are addressed.