Synergistic HNO₃-H₂SO₄-NH₃ upper tropospheric particle formation.

ABSTRACT: New particle formation in the upper free troposphere is a major global source of cloud condensation nuclei (CCN)^1-4. However, the precursor vapours that drive the process are not well understood. With experiments performed under upper tropospheric conditions in the CERN CLOUD chamber, we show that nitric acid, sulfuric acid and ammonia form particles synergistically, at rates that are orders of magnitude faster than those from any two of the three components. The importance of this mechanism depends on the availability of ammonia, which was previously thought to be efficiently scavenged by cloud droplets during convection. However, surprisingly high concentrations of ammonia and ammonium nitrate have recently been observed in the upper troposphere over the Asian monsoon region

SUBMITTER: Wang M 

PROVIDER: S-EPMC9117139 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature