Characteristics, secondary transformation, and health risk assessment of ambient volatile organic compounds (VOCs) in urban Beijing, China

Abstract The long-term and high temporal resolution measurement of ambient volatile organic compounds (VOCs) was continuously performed in urban Beijing in 2016. Historical VOC data were compiled and compared with our results. A positive matrix factorization (PMF) model was used to determine potential emission sources. The backward trajectories and the concentration, ozone formation potential (OFP), and secondary organic aerosol potential (SOAP) of VOCs in the air masses from different regions were used to estimate the VOC chemical behaviour and transport-direction contributions. A health assessment, including the carcinogenic risk and non-carcinogenic risk of specific hazardous VOC species, was performed, while the point estimate approach was used for risk apportionment based on emission sources. In this study, the average (±standard deviation, Std) concentration of total observed VOCs (TVOCs) was 101.5 ± 65.2 μg/m3, ranging from 21.4 to 439.1 μg/m3. The VOC concentration in Beijing had decreased but was still higher than that in other Chinese cities according to compiled reported VOC data. Combustion-related sources were the primary sources of VOC pollution in urban Beijing. VOC contributions were increasingly coming from the northwestern regions instead of solely from regions to the south of Beijing according to the VOC concentration, OFP, and SOAP data. A potential health risk from VOCs should be considered for residents living in Beijing. The results of this study are expected to provide basic data for efficient VOC emission management and public health protection in Beijing.