Black carbon (BC) is a strong climate forcer, but considerable uncertainty remains in estimating its radiative impact, largely due to persistent gaps between observed and modeled light absorption enhancement (<em>E</em><sub>abs</sub>). In this study, we employed a Centrifugal Particle Mass Analyzer and Single Particle Soot Photometer tandem system to characterize mass ratio (<em>M</em><sub>R</sub>, coating-to-BC) and morphology of BC-containing particles in Hangzhou, China. Fortunately, low, medium, and high <em>E</em><sub>abs</sub> values were observed during a single field campaign. Results show that the uniform core-shell Mie model overestimated <em>E</em><sub>abs</sub> especially in clean conditions (low <em>E</em><sub>abs</sub>). A morphology-dependent correction scheme was developed to improve optical property estimates of BC in the “transition state.” This improved model better reproduces measured <em>E</em><sub>abs</sub> in different pollution conditions and reveals that the concentrations of particle chemical composition affect the <em>M</em><sub>R</sub> threshold defining this state. Our findings highlight the need to account for real-world particle complexity in climate-relevant BC modeling.