A predictive model for adsorptive gas partitioning of SOCs on fine atmospheric inorganic dust particles

The adsorptive gas/particle (G/P) partitioning of semivolatile organic compounds (SOCs) on inorganic Arizona road dust was studied using outdoor Teflon film chambers. Physicochemical parameters from SOC molecular structural information were implemented to describe nonspecific and specific interactions relating to G/P adsorption. Experimental partitioning data were successfully interpreted using physicochemical parameters such as vapor pressure, molecular polarizability, and solute solvation. To evaluate the effect of surface functional groups on the adsorptive G/P partitioning of SOCs, untreated and baked Arizona road dust particles were used. The partitioning coefficients, K-p, for a range of different SOCs on baked dust particles and on untreated dust particles were measured from simultaneous experiments in two outdoor Teflon film chambers that were operated at the same temperature and humidity conditions. K-p values for the two different surface properties of untreated and baked particles were better predicted by including solute solvation parameters than just by vapor pressure alone.