Owing to rapid economic and industrial development,China has been suffering from degraded air quality and visibility.Volatile organic compounds (VOCs) are important precursors to the formation of ground-level ozone and hence photochemical smog.Some VOCs adversely affect human health.Therefore,VOCs have recently elicited public conc and given new impetus to scientific interest.China is now implementing a series of polices to control VOCs pollution.The key to formulating policy is understanding the ambient VOCs pollution status.This paper mainly analyzes the species,levels,sources,and spatial distributions of VOCs in ambient air.The results show that the concentrations of ambient VOCs in China are much higher than those of developed countries such as the United States and Japan,especial benzene,which exceeds available standards.At the same time,the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) of various VOCs are calculated.Aromatics and alkenes have much higher OFPs,while aromatics have higher SOAFP.The OFPs of ambient VOCs in the cities of Beijing,Guangzhou and Changchun are very high,and the SOAFP of ambient VOCs in the cities of Hangzhou,Guangzhou and Changchun are higher.