Seasonal source contributions of tropospheric ozone over East Asia based on CMAQ-HDDM

► HDDM was used to estimate ozone source contributions over East Asia. ► The seasonal characteristics of ozone concentrations were well reproduced. ► An ozone-sensitive regime was diagnosed based on the HDDM results. ► NOx was identified as the most significant precursor of O3, rather than VOC. ► Ozone source contributions from China are largest during spring.