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Guo W, Yang Y, Chen Q, Zhu Y, Zhang Y, Zhang Y, Liu Y, Li G, Sun W, She J. Chemical reactivity of volatile organic compounds and their effects on ozone formation in a petrochemical industrial area of Lanzhou, Western China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:155901. [PMID: 35569665 DOI: 10.1016/j.scitotenv.2022.155901] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/09/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Measurements of ozone (O3) and its precursors were performed in the summer of 2019 in Lanzhou, a petrochemical industrial city, to better understand the reactivity of volatile organic compounds (VOCs) and their effects on O3 production. During the campaign, the daily maximum 8-hour average (MDA8) O3, NO2, and total VOC (TVOC) concentrations reached 72.2 ± 19.9 ppb, 24.9 ± 10.8 ppb, and 50.8 ± 46.1 ppb, respectively. Alkanes, alkenes, halocarbons, aromatics, and alkynes contributed 45.3%, 24.0%, 16.5%, 10.0%, and 4.2% to TVOCs, respectively. The OH reactivity and relative incremental reactivity (RIR) of VOCs at different times were calculated. The results indicated that alkenes played a predominant role, accounting for an average of 68.5% of the initial VOC reactivity. Compared to other regions, alkenes are relatively more important for O3 formation in the petrochemical industry area of Lanzhou, while aromatics are relatively less important. Generally, O3 formation occurred in a VOC-limited regime in the morning and in a transitional regime in the afternoon. The response surface methodology (RSM) combined with a chemical box model was applied to obtain relationships between O3 and its precursors and determine the most effective way to reduce the O3 concentration. Reduction in the non-alkene concentration slightly affected the O3 concentration. In contrast, the effect of nitrogen oxides (NOx) was closely related to the alkene concentration, and NOx concentration reduction could lead to an increase in the O3 concentration when alkenes were abated to less than 80% of the present concentration. To mitigate O3 pollution near the petrochemical industrial area of Lanzhou, reducing the alkene concentration, especially the C4 alkene concentration (1,3-butadiene, cis-2-butene, and trans-2-butene), was the fastest and most effective control strategy. The results of this study serve as a reference for O3 pollution control in petrochemical industrial areas.
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Affiliation(s)
- Wenkai Guo
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yanping Yang
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China; Northwest Institute of Eco-environmental Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Gansu Environmental Monitoring Center, Lanzhou 730000, China
| | - Qiang Chen
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Yuhuan Zhu
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yaru Zhang
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yingnan Zhang
- Environment Research Institute, Shandong University, Jinan 250000, China
| | - Yongle Liu
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Guangyao Li
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Wei Sun
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jing She
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
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Michael R, O'Lenick CR, Monaghan A, Wilhelmi O, Wiedinmyer C, Hayden M, Estes M. Application of geostatistical approaches to predict the spatio-temporal distribution of summer ozone in Houston, Texas. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2019; 29:806-820. [PMID: 30451934 DOI: 10.1038/s41370-018-0091-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 09/09/2018] [Accepted: 09/17/2018] [Indexed: 06/09/2023]
Abstract
Mitigation of adverse effects of air pollution requires understanding underlying exposures, such as ambient ozone concentrations. Geostatistical approaches were employed to analyze temporal trends and estimate spatial patterns of summertime ozone concentrations for Houston, Texas, based on hourly ozone observations obtained from the Texas Commission on Environmental Quality. We systematically assess the accuracy of several spatial interpolation methods, comparing inverse distance weighting, simple kriging, ordinary kriging, and universal kriging methods utilizing the hourly ozone observations and meteorological measurements from monitoring sites. Model uncertainty was assessed by leave-one-out cross-validation. Kriging methods performed better, showing greater consistency in the generated surfaces, fewer interpolation errors, and lower biases. Universal kriging did not significantly improve the interpolation results compared to ordinary kriging, and thus ordinary kriging was determined to be the optimal method, striking a balance between accuracy and simplicity. The resulting spatial patterns indicate that the more industrialized areas east and northeast of Houston exhibit the highest summertime ozone concentrations. Estimated daily maximum 8 h ozone concentration fields generated will be used to inform research on population health risks from exposure to surface ozone in Houston.
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Affiliation(s)
- Ryan Michael
- Research Applications Laboratory, National Center for Atmospheric Research, Boulder, CO, USA.
| | - Cassandra R O'Lenick
- Research Applications Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Andrew Monaghan
- Research Applications Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Olga Wilhelmi
- Research Applications Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Christine Wiedinmyer
- Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Mary Hayden
- Research Applications Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Mark Estes
- Air Modeling and Data Analysis Section, Texas Commission on Environmental Quality, Austin, TX, USA
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Hidy GM, Blanchard CL. Precursor reductions and ground-level ozone in the Continental United States. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2015; 65:1261-82. [PMID: 26252366 DOI: 10.1080/10962247.2015.1079564] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
UNLABELLED Numerous papers analyze ground-level ozone (O₃) trends since the 1980s, but few have linked O₃trends with observed changes in nitrogen oxide (NOx) and volatile organic compound (VOC) emissions and ambient concentrations. This analysis of emissions and ambient measurements examines this linkage across the United States on multiple spatial scales from continental to urban. O₃concentrations follow the general decreases in both NOx and VOC emissions and ambient concentrations of precursors (nitrogen dioxide, NO₂; nonmethane organic compounds, NMOCs). Annual fourth-highest daily peak 8-hr average ozone and annual average or 98th percentile daily maximum hourly NO₂concentrations show a statistically significant (p < 0.05) linear fit whose slope is less than 1:1 and intercept is in the 30 to >50 ppbv range. This empirical relationship is consistent with current understanding of O₃photochemistry. The linear O₃-NO₂relationships found from our multispatial scale analysis can be used to extrapolate the rate of change of O₃with projected NOx emission reductions, which suggests that future declines in annual fourth-highest daily average 8-hr maximum O₃concentrations are unlikely to reach 65 ppbv or lower everywhere in the next decade. Measurements do not indicate increased annual reduction rates in (high) O₃concentrations beyond the multidecadal precursor proportionality, since aggressive measures for NOx and VOC reduction are in place and have not produced an accelerated O₃reduction rate beyond that prior to the mid-2000s. Empirically estimated changes in O₃with emissions suggest that O₃is less sensitive to precursor reductions than is found by the CAMx (v. 6.1) photochemical model. Options for increasing the rate of O₃change are limited by photochemical factors, including the increase in NOx sensitivity with time (NMOC/NOx ratio increase), increase in O₃production efficiency at lower NOx concentrations (higher O₃/NOy ratio), and the presence of natural NOx and NMOC precursors and background O₃. IMPLICATIONS This analysis demonstrates empirical relations between O₃and precursors based on long term trends in U.S. LOCATIONS The results indicate that ground-level O₃concentrations have responded predictably to reductions in VOC and NOx since the 1980s. The analysis reveals linear relations between the highest O₃and NO₂concentrations. Extrapolation of the historic trends to the future with expected continued precursor reductions suggest that achieving the 2014 proposed reduction in the U.S. National Ambient Air Quality Standard to a level between 65 and 70 ppbv is unlikely within the next decade. Comparison of measurements with national results from a regulatory photochemical model, CAMx, v. 6.1, suggests that model predictions are more sensitive to emissions changes than the observations would support.
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