Temperature dependence of the rain-gas and snow-gas partition coefficients for nearly a thousand chemicals.

Compared to the particle-gas partition coefficients (K _PG ), the rain-gas (K _RG ) and snow-gas (K _SG ) partition coefficients are also essential in studying the environmental behavior and fate of chemicals in the atmosphere. While the temperature dependence for the K _PG have been extensively studied, the study for K _RG and K _SG are still lacking. Adsorption coefficients between water surface-air (K _IA ) and snow surface-air (K _JA ), as well as partition coefficients between water-air (K _WA ) and octanol-air (K _OA ) are vital in calculating K _RG and K _SG . These four basic adsorption and partition coefficients are also temperature-dependent, given by the well-known two-parameters Antoine equation logK _XY  = A _XY  + B _XY /T, where K _XY is the adsorption or partition coefficients, A _XY and B _XY are Antoine parameters (XY stand for IA, JA, WA, and OA), and T is the temperature in Kelvin. In this study, the parameters A _XY and B _XY are calculated for 943 chemicals, and logK _XY can be estimated at any ambient temperature for these chemicals using these Antoine parameters. The results are evaluated by comparing these data with published experimental and modeled data, and the results show reasonable accuracy. Based on these coefficients, temperature-dependence of logK _RG and logK _SG is studied. It is found that both logK _RG and logK _SG are linearly related to 1/T, and Antoine parameters for logK _RG and logK _SG are also estimated. Distributions of the 943 chemicals in the atmospheric phases (gas, particle, and rain/snow), are illustrated in a Chemical Space Map. The findings reveal that, at environmental temperatures and precipitation days, the dominant state for the majority of chemicals is the gaseous phase. All the A _XY and B _XY values for logK _SG , logK _RG , and basic adsorption and partition coefficients, both modeled by this study and collected from published work, are systematically organized into an accessible dataset for public utilization.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)