Volatile organic compounds in a typical petrochemical industrialized valley city of northwest China based on high-resolution PTR-MS measurements: Characterization, sources and chemical effects

Xi Zhou; Zhongqin Li; Tinjun Zhang; Fanglin Wang; Feiteng Wang; Yan Tao; Xin Zhang; Fanglong Wang; Ju Huang

doi:10.1016/j.scitotenv.2019.03.283

Volatile organic compounds in a typical petrochemical industrialized valley city of northwest China based on high-resolution PTR-MS measurements: Characterization, sources and chemical effects

Sci Total Environ. 2019 Jun 25:671:883-896. doi: 10.1016/j.scitotenv.2019.03.283. Epub 2019 Mar 22.

Authors

Xi Zhou¹, Zhongqin Li², Tinjun Zhang³, Fanglin Wang⁴, Feiteng Wang⁵, Yan Tao⁴, Xin Zhang⁶, Fanglong Wang⁶, Ju Huang⁴

Affiliations

¹ Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China; State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Tianshan Glaciological Station, Chinese Academy of Sciences, Lanzhou 730000, China.
² State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Tianshan Glaciological Station, Chinese Academy of Sciences, Lanzhou 730000, China; College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730000, China. Electronic address: lizq@lzb.ac.cn.
³ Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China; University Corporation for Polar Research, Beijing 100875, China.
⁴ Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
⁵ State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Tianshan Glaciological Station, Chinese Academy of Sciences, Lanzhou 730000, China.
⁶ College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730000, China.

PMID: 30947059
DOI: 10.1016/j.scitotenv.2019.03.283

Abstract

To scientifically understand the emissions and chemistry of volatile organic compounds (VOCs) in a typical petrochemical industrialized and dust-rich region of Northwest China, VOCs were measured at a receptor site in the Lanzhou Valley using a high-resolution online proton transfer reaction-mass spectrometer (PTR-MS). The ranking of VOC mixing ratios was methanol (32.72 ± 8.94 ppb) > acetaldehyde (5.05 ± 2.4 ppb) > acetic acid (3.42 ± 1.71 ppb). Lanzhou has higher oxygenated VOCs (OVOCs) mixing ratios (methanol and acetaldehyde) and lower aromatics levels (benzene, toluene and C8-aromatics) compared with other cities. The positive matrix factorization (PMF) model showed eight sources of VOCs as follows: (1) mixed industrial process-1 (13.5%), (2) secondary formation (13.2%), (3) mixed industrial process-2 (11.8%), (4) residential biofuel use and waste disposal (13.80%), (5) solvent usage (10.1%), (6) vehicular exhaust (11.8%), (7) biogenic (13.8%) and (8) biomass burning (12.0%). Both the PSCF and the CWT results of mixed industrial process-1 were mainly from the northeast of Lanzhou and the biomass burning was from the southeast; the other four sources (without secondary formation and biogenic) were mainly from the west and northwest of Lanzhou, which were associated with the dust area of the Gobi Desert. A trajectory sector analysis revealed that the local emissions contributed 64.9-71.1% to the VOCs. OVOCs accounted for 43% of the ozone production potential (OFP), and residential biofuel use and waste disposal (25.1%), mixed industrial process-2 (15.3%) and solvent usage (13.4%) appeared to be the dominant sources contributors to O₃ production. The rank of main secondary organic aerosols (SOA) precursors under low-NOx conditions is xylene > toluene > benzene > naphthalene > styrene > C10-aromatics > isoprene, while under high-NOx conditions, it is toluene > naphthalene > xylene > C10-aromatics > styrene > benzene > isoprene. Solvent usage and vehicular exhaust appeared to be the dominant contributors to SOA formation.

Keywords: Lanzhou; OFP; PTR-MS; SOAF; Source apportionment; VOCs.