Articles | Volume 18, issue 7
Atmos. Chem. Phys., 18, 4567–4595, 2018
Atmos. Chem. Phys., 18, 4567–4595, 2018

Research article 05 Apr 2018

Research article | 05 Apr 2018

Monitoring of volatile organic compounds (VOCs) from an oil and gas station in northwest China for 1 year

Huang Zheng1,2, Shaofei Kong1, Xinli Xing2,3, Yao Mao3, Tianpeng Hu2, Yang Ding2, Gang Li4, Dantong Liu5, Shuanglin Li1, and Shihua Qi1,3 Huang Zheng et al.
  • 1Department of Atmospheric Sciences, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
  • 2Department of Environmental Science and Technology, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
  • 3State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China
  • 4Karamay Environmental Monitoring Center Station, Karamay, 834000, China
  • 5School of Earth and Environmental Sciences, the University of Manchester, M13 9PL, UK

Abstract. Oil and natural gas are important for energy supply around the world. The exploring, drilling, transportation and processing in oil and gas regions can release a lot of volatile organic compounds (VOCs). To understand the VOC levels, compositions and sources in such regions, an oil and gas station in northwest China was chosen as the research site and 57 VOCs designated as the photochemical precursors were continuously measured for an entire year (September 2014–August 2015) using an online monitoring system. The average concentration of total VOCs was 297 ± 372 ppbv and the main contributor was alkanes, accounting for 87.5 % of the total VOCs. According to the propylene-equivalent concentration and maximum incremental reactivity methods, alkanes were identified as the most important VOC groups for the ozone formation potential. Positive matrix factorization (PMF) analysis showed that the annual average contributions from natural gas, fuel evaporation, combustion sources, oil refining processes and asphalt (anthropogenic and natural sources) to the total VOCs were 62.6 ± 3.04, 21.5 ± .99, 10.9 ± 1.57, 3.8 ± 0.50 and 1.3 ± 0.69 %, respectively. The five identified VOC sources exhibited various diurnal patterns due to their different emission patterns and the impact of meteorological parameters. Potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models based on backward trajectory analysis indicated that the five identified sources had similar geographic origins. Raster analysis based on CWT analysis indicated that the local emissions contributed 48.4–74.6 % to the total VOCs. Based on the high-resolution observation data, this study clearly described and analyzed the temporal variation in VOC emission characteristics at a typical oil and gas field, which exhibited different VOC levels, compositions and origins compared with those in urban and industrial areas.

Short summary
This research is the first study concerning the 1-year online monitoring of volatile organic compounds in an oil–gas field in China. The VOC concentrations, compositions and ozone formation potential in this study are quite different from other research. The contributions of natural gas and the other four sources to total VOCs are quantified. The different timescale variations in different sources are described. This research broadens our knowledge of VOC behavior in this type of region.
Final-revised paper