Aerosol pH is well-buffered by alkaline compounds, notably NH3 and in some areas crustal elements. NH3 is found to supply remarkable buffering capacity on a global scale, from the polluted continents to the remote oceans. Potential future changes in agricultural NH3 must be accompanied by strong reductions of SO2 and NOx to avoid that aerosols become highly acidic with implications for human health (aerosol toxicity), ecosystems (acid deposition), clouds and climate (aerosol hygroscopicity).
Aerosol pH is well-buffered by alkaline compounds, notably NH3 and in some areas crustal...
Review status: this preprint is currently under review for the journal ACP.
How alkaline compounds control atmospheric aerosol acidity
Vlassis A. Karydis1,a,Alexandra P. Tsimpidi1,a,2,Andrea Pozzer1,3,and Jos Lelieveld1,4Vlassis A. Karydis et al.Vlassis A. Karydis1,a,Alexandra P. Tsimpidi1,a,2,Andrea Pozzer1,3,and Jos Lelieveld1,4
Received: 26 Nov 2020 – Accepted for review: 18 Dec 2020 – Discussion started: 22 Dec 2020
Abstract. The acidity of atmospheric aerosols regulates the particulate mass, composition and toxicity, and has important consequences for public health, ecosystems and climate. Despite these broad impacts, the global distribution and evolution of aerosol acidity are unknown. We used the particular, comprehensive atmospheric multiphase chemistry – climate model EMAC to investigate the main factors that control aerosol acidity, and uncovered remarkable variability and unexpected trends during the past 50 years in different parts of the world. We find that alkaline compounds, notably ammonium, and to a lesser extent crustal cations, buffer the aerosol pH on a global scale. Given the importance of aerosols for the atmospheric energy budget, cloud formation, pollutant deposition and public health, alkaline species hold the key to control strategies for air quality and climate change.
Aerosol pH is well-buffered by alkaline compounds, notably NH3 and in some areas crustal elements. NH3 is found to supply remarkable buffering capacity on a global scale, from the polluted continents to the remote oceans. Potential future changes in agricultural NH3 must be accompanied by strong reductions of SO2 and NOx to avoid that aerosols become highly acidic with implications for human health (aerosol toxicity), ecosystems (acid deposition), clouds and climate (aerosol hygroscopicity).
Aerosol pH is well-buffered by alkaline compounds, notably NH3 and in some areas crustal...