Multiphase buffer theory explains contrasts in atmospheric aerosol acidity
- 1Minerva Research Group, Max Planck Institute for Chemistry, Mainz 55128, Germany
- 2Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
- 3Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
- 4Department of Geology and Geophysics, King Saud University, P.O Box. 2455, 11451 Riyadh, Saudi Arabia
Aerosol acidity largely regulates the chemistry of atmospheric particles, and resolving the drivers of aerosol pH is key to understanding their environmental effects. We find that an individual buffering agent can adopt different buffer pH values in aerosols and that aerosol pH levels in populated continental regions are widely buffered by the conjugate acid-base pair NH4+/NH3 (ammonium/ammonia). We propose a multiphase buffer theory (Zheng et al., 2020, Science) to explain these large shifts of buffer pH, and we show that aerosol water content and mass concentration play a more important role in determining aerosol pH in ammonia-buffered regions than variations in particle chemical composition. Our results imply that aerosol pH and atmospheric multiphase chemistry are strongly affected by the pervasive human influence on ammonia emissions and the nitrogen cycle in the Anthropocene.
References:
Zheng, G., Su, H.*, Wang, S., Andreae, M. O., Pöschl, U., and Cheng, Y.*: Multiphase buffer theory explains contrasts in atmospheric aerosol acidity, Science, 369, 1374-1377, 2020.
How to cite: Zheng, G., Su, H., Wang, S., Andreae, M., Pöschl, U., and Cheng, Y.: Multiphase buffer theory explains contrasts in atmospheric aerosol acidity, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4936, https://doi.org/10.5194/egusphere-egu21-4936, 2021.
