Characteristics of volatile organic compounds in 11 cities along Taihang Mountain, an industrial region in Northern China

The cities along Taihang Mountain, one of the most important industrial regions in China, have faced challenges in atmospheric pollution control due to the development of industries. However, few studies have focused on the pollution characteristics of volatile organic compounds (VOCs) in this region. The concentrations, composition, sources, and chemical reactivity of VOCs were analyzed in 11 cities along Taihang Mountain. The average VOC concentration in the 11 cities (31.4 +/- 11.3 ppbv) was higher than that for most cities in China, which was attributed to emissions from coal combustion and industrial processes. Four cities in Hebei province had the highest VOC concentration (32.9 +/- 10.9 ppbv). Alkene (7.4 +/- 3.9 ppbv) and alkyne (2.6 +/- 1.9 ppbv) concentrations in the 11 cities were higher than those in other Chinese cities (2.4-5.9 and 1.0-3.8 ppbv, respectively). Shanxi Province had the largest contributions of alkenes (23.6%) and alkynes (9.7%). Based on the benzene/ toluene (B/T) ratio, the 11 cities were divided into three categories: four had B/T ratios of 0.5-0.6, and were classified the traffic cities, and four with B/T ratios of 1.5-2.2 were classified as coal combustion cities. The chemical reactivity results showed that alkenes were the most important VOCs in terms of ozone formation. Coal combustion and industrial processes were the main emission sources affecting VOCs and O3 pollution in the 11 cities along Taihang Mountain. VOC researchers should pay more attention to this region, and more refined research should be conducted.