Vertical characteristics of carbonaceous species and their source contributions in a Chinese mega city

► OC and EC in PM10 were measured at four heights on a tower in Tianjin. ► SOC formation and transportation affected OC more strongly at higher heights. ► SOC was estimated by the minimum OC/EC, NCPCRCMB and CMB-Iteration methods. ► It is more effective for excess OC to control the vehicle and coal sources.