Fine particulate matter (PM2.5) is known to have an adverse impact on health and climate. Secondary organic aerosol (SOA) is a source of PM 2.5 and the multiphase reactions of isoprene epoxydiols (IEPOX) is an important reaction pathway. Current chemical transport models do not include the impact of organic coatings of aerosols on IEPOX-derived SOA formation. This work for the first time predicts coating impact on IEPOX-derived SOA formation with the new lab based kinetic data and a 0-Dimentional model that reduced 31% SOA formation. It was found that Henry's law constant (H) increase10-fold led to 8-fold increase in IEPOX-derived SOA concentration. Diffusion coefficient of organic coating (Dorg) was also critical on predicting IEPOX-derived SOA formation. Studies relying on different approaches resulted in a range of Dorg value from 10 9 m2/s to 1014 m2/s resulting 1-100% SOA reduction. Assumptions regarding the RH above which diffusivity limitations were negligible also affected the model SOA predictions.