Search for: All records

Abstract As one of the least understood aerosol processes, nucleation can be a dominant source of atmospheric aerosols. Sulfuric acid (SA)-amine binary nucleation with dimethylamine (DMA) has been recognized as a governing mechanism in the polluted continental boundary layer. Here we demonstrate the importance of trimethylamine (TMA) for nucleation in the complex atmosphere and propose a molecular-level SA-DMA-TMA ternary nucleation mechanism as an improvement upon the conventional binary mechanism. Using the proposed mechanism, we could connect the gaseous amines to the SA-amine cluster signals measured in the atmosphere of urban Beijing. Results show that TMA can accelerate the SA-DMA-based new particle formation in Beijing by 50–100%. Considering the global abundance of TMA and DMA, our findings imply comparable importance of TMA and DMA to nucleation in the polluted continental boundary layer, with probably higher contributions from TMA in polluted rural environments and future urban environments with controlled DMA emissions. 

Abstract Aerosol particles are important for our global climate, but the mechanisms and especially the relative importance of various vapors for new particles formation (NPF) remain uncertain. Quantum chemical (QC) studies on organic enhanced nucleation has for the past couple of decades attracted immense attention, but very little remains known about the exact organic compounds that potentially are important for NPF. Here we comprehensively review the QC literature on atmospheric cluster formation involving organic compounds. We outline the potential cluster systems that should be further investigated. Cluster formation involving complex multi‐functional organic accretion products warrant further investigations, but such systems are out of reach with currently applied methodologies. We suggest a “cluster of functional groups” approach to address this issue, which will allow for the identification of the potential structure of organic compounds that are involved in atmospheric NPF. This article is categorized under:Theoretical and Physical Chemistry > Reaction Dynamics and KineticsSoftware > Quantum ChemistryTheoretical and Physical Chemistry > ThermochemistryMolecular and Statistical Mechanics > Molecular Interactions