In China,volatile organic compound (VOC) control directives have been continuously released and implemented for important sources and regions to tackle air pollution.The corresponding control requirements were based on VOC emission amounts (EA),but never considered the significant differentiation of VOC species in terms of atmospheric chemical reactivity.This will adversely influence the effect of VOC reduction on air quality improvement.Therefore,this study attempted to develop a comprehensive classification method for typical VOC sources in the Beijing-Tianjin-Hebei region (BTH),by combining the VOC emission amounts with the chemical reactivities of VOC species.Firstly,we obtained the VOC chemical profiles by measuring 5 key sources in the BTH region and referencing another 10 key sources,and estimated the ozone formation potential (OFP) per ton VOC emission for these sources by using the maximum incremental reactivity (MIR) index as the characteristic of source reactivity (SR).Then,we applied the data normalization method to respectively convert EA and SR to normalized EA (NEA) and normalized SR (NSR) for various sources in the BTH region.Finally,the control index (CI) was calculated,and these sources were further classified into four grades based on the normalized CI (NCI).The study results showed that in the BTH region,fumiture coating,automobile coating,and road vehicles are characterized by high NCI and need to be given more attention;however,the petro-chemical industry,which was designated as an important control source by air quality managers,has a lower NCI.