The Radical Volatility Basis Set Reaches from CLOUD to the Clouds

Abstract:

For new-particle formation to influence clouds and climate, particles must grow from about 1 nm to 50-100 nm in diameter to avoid coagulation loss, and so both nucleation rates and particle survival (thus growth rates) are critical. Organic vapors capable of driving formation and growth must reach exceptionally low vapor pressures, and the gas-phase autoxidation and multi-generation oxidation connects to peroxy radical chemistry and multiple potential termination routes. This in turn causes the formation and growth rates to depend strongly on temperature, nitrogen oxides, and the specific mix of peroxy radicals. Both direct and indirect climate forcing by aerosols are by definition the change in aerosol-climate effects over time, from the pre-industrial to the present day and also into the future as pollution controls and low-carbon energy sources change emissions dramatically. It is thus vital to gain an understanding of the nonlinear interactions that govern these effects. Here we shall describe a representation of peroxy radicals within the Volatility Basis Set framework, and both the intrinsic sensitivity of the system as well as experimental constraints to critical kinetics.