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Abstract Atmospheric aerosol particles impact Earth's radiation balance by acting as seeds for cloud droplet formation. Over half of global cloud seed particles are formed by nucleation, a process where gas‐phase compounds react to form stable particles. Reactions of sulfuric acid (SA) with a wide variety of atmospheric compounds have been previously shown to drive nucleation in the lower troposphere. However, global climate models poorly predict particle nucleation rates since current nucleation models do not describe nucleation for systems containing tens to hundreds of precursor compounds. The nucleation potential model (NPM) was recently developed to model SA nucleation of complex mixtures by measuring an effective base concentration using a 1‐nm condensation particle counter. This technique for estimating particle nucleation rates can be deployed at a much higher spatial and temporal resolution than current methods which require detailed knowledge of all nucleation reactions and measurements, typically using a mass spectrometer, of all nucleation precursor gases. This work expands NPM by showing that this model can capture enhancement and suppression of SA nucleation rates within a complex mixture of organic and inorganic acids, ambient air, and across a range of atmospherically relevant relative humidities. In addition, an expression for calculating atmospheric nucleation rates was also derived from the NPM. Ultimately, NPM provides a simple way to measure and model the extent compounds in a complex mixture enhance SA nucleation rates using a condensation particle counter. 

Abstract. Observations over the last decade have demonstrated that theatmosphere contains potentially hundreds of compounds that can react withsulfuric acid to nucleate stable aerosol particles. Consequently, modelingatmospheric nucleation requires detailed knowledge of nucleation reactionkinetics and spatially and temporally resolved measurements of numerousprecursor compounds. This study introduces the Nucleation Potential Model(NPM), a novel nucleation model that dramatically simplifies the diversereactions between sulfuric acid and any combination of precursor gases. The NPMpredicts 1 nm nucleation rates from only two measurable gas concentrations,regardless of whether all precursor gases are known. The NPM describes sulfuricacid nucleating with a parameterized base compound at an effective baseconcentration, [Beff]. [Beff] captures the ability of a compoundor mixture to form stable clusters with sulfuric acid and is estimated frommeasured 1 nm particle concentrations. The NPM is applied to experimental andfield observations of sulfuric acid nucleation to demonstrate how[Beff] varies for different stabilizing compounds, mixtures, andsampling locations. Analysis of previous field observations shows distinctdifferences in [Beff] between locations that follow the emissionsources and stabilizing compound concentrations for that region. Overall,the NPM allows researchers to easily model nucleation across diverseenvironments and estimate the concentration of non-sulfuric acid precursorsusing a condensation particle counter.