Effect of methyl hydrogen sulfate on the formation of sulfuric acid‐ammonia clusters: A theoretical study

Abstract

Methyl hydrogen sulfate (MHS) as a common nucleation precursor that has important effect on new particle formation (NPF). Liu et al. showed that MHS and sulfuric acid (SA) generation are competitive due to consumption of the common precursor SO 3 , and the nucleation ability of SA is better than MHS. Thus, MHS inhibits the SA-DMA-based clusters formation particularly in regions with high [MO] (methanol) (Liu et al., Proc. Natl. Acad. Sci. U.S.A. 2019, 116, 24,966). However, in regions where [H 2 O] is much higher than [MO] ([SA] > > [MHS]), the SO 3 consumed by the generation of less MHS will not significantly reduce the [SA], whether MHS still inhibits SA-A-based clusters formation and how MHS affects the growth pathways of MHS-SA-A-based clusters remains unclear. Hence, quantum chemistry calculations combining Atmospheric Cluster Dynamics Code (ACDC) are used to investigate the role of MHS in the SA-A-based system. Our conclusions show two different effects of MHS in NPF process: "inhibiting" in regions with high [MO] and "weakly facilitating" in regions with high [H 2 O] and low [MO]. The growth pathways show that with the increasing [MHS], the role of MHS in NPF gradually changes from "transporter" to "participator", and the contribution to the pathways increases from 7 to 85%. Our results contribute to understanding the NPF in low-temperature regions with different concentrations of MO and H 2 O. K E Y W O R D S ammonia (a), growth pathway, methyl hydrogen sulfate (MHS), new particle formation (NPF), sulfuric acid (SA)

Reaction of SO3 with H2SO4 and Its Implication for Aerosol Particle Formation in the Gas Phase and at the Air-Water Interface

“…Moreover, we evaluated the enhancing potential of S2O7 2on SA-A cluster by considering geometrical structure and the formation free energies of the (SA)1(A)1(S2O7 2-)1 clusters. As compared with (SA)1(A)1(X)1 (X = HOOCCH2COOH, HOCCOOSO3H, CH3OSO3H, HOOCCH2CH(NH2)COOH and HOCH2COOH) clusters (Zhong et al, 2019;Zhang et al, 2018;Rong et al, 2020;Gao et al, 2023;Liu et al, 2021a;Zhang et al, 2017), the number of hydrogen bonds in (SA)1(A)1(S2O7 2-)1 cluster presented in Fig. Subsequently, comparing to (SA)1(A)1(X)1 clusters (Table 2), the Gibbs formation free energy ∆G of (SA)1(A)1(S2O7 2-)1 cluster is lower.…”