The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach. coupled with SAPRC-99 gas-phase chemistry mechanism. is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. https://parisnaturalfoodes.shop/product-category/ff-shampoo/