Wang S, Peng Y, Zhang Q, Wang W, Wang Q. Mechanistic understanding of rapid H
2SO
4-HNO
3-NH
3 nucleation in the upper troposphere.
THE SCIENCE OF THE TOTAL ENVIRONMENT 2023;
883:163477. [PMID:
37062321 DOI:
10.1016/j.scitotenv.2023.163477]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/30/2023] [Accepted: 04/09/2023] [Indexed: 06/03/2023]
Abstract
The upper troposphere (UT) nucleation is thought to be responsible for at least one-third of the global cloud condensation nuclei. Although NH3 was considered to be extremely rare in the UT, recent studies show that NH3 is convected aloft, promoting H2SO4-HNO3-NH3 rapid nucleation in the UT during the Asian monsoon. In this study, the roles of HNO3, H2SO4 (SA), and NH3 in the nucleation of SA-HNO3-NH3 were investigated by quantum chemical calculation and molecular dynamic (MD) simulations at the level of M06-2×/6-31 + G (d, p). The nucleation ability of SA-HNO3-NH3 is suppressed as the temperature increases in the UT. The results indicated that bisulfate (HSO4-), nitrate (NO3-), and ammonium (NH4+) ionized from SA, HNO3, and NH3, respectively, can significantly enhance the nucleation ability of SA-HNO3-NH3. In addition, hydrated hydrogen ion (H3O+) as well as sulfate ions (SO42-) ionized by SA can also actively participate in the process of ion-induced nucleation. The results reveal that the enhancement effect of five ions on the SA-HNO3-NH3 nucleation can be ordered as follows: SO42- > H3O+ > HSO4- > NO3- > NH4+. Many ion-induced nucleation pathways of SA-HNO3-NH3 with the Gibbs free energies of formation (ΔG) lower than -100 kcal mol-1 were energetically favorable. HNO3 and NH3 can promote the nucleation of SA-HNO3-NH3 and water (W) molecules are also beneficial to promote the new particle formation (NPF) of SA-HNO3-NH3. Under the action of H-bonds and electrostatic interaction, ion-induced nucleation could lead to the rapid nucleation of H2SO4-HNO3-NH3 in the UT.
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