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Abstract An extensive set of primary and secondary pollutants was measured at a ground site in a remote location in the Yellow River Delta, China during the Ozone Photochemistry and Export from China Experiment (OPECE) from March to April 2018. The measurements include volatile organic compounds (VOCs), peroxyacyl nitrates (PANs), ozone (O3), particulate species, nitrogen oxides (NOx), and SO2. Observed VOC mixing ratios were comparable to those measured in heavily polluted cities in the U.S. and China. The VOC source signatures suggest a strong influence from Oil and Natural Gas (O&NG) emissions with potentially large contributions from Liquified Petroleum Gas (LPG) sources as well. Consistently elevated concentrations of O3, PAN, and its rarely measured homologs peroxybenzoylic nitric anhydride (PBzN) and peroxyacrylic nitric anhydride (APAN) at the OPECE site indicate complex photochemistry in a heterogeneous VOC environment. Diagnostic 0‐D box model simulations are used to investigate the budgets of ROx(OH + HO2 + RO2), and the rate and efficiency of O3production. Model sensitivity calculations indicate that O3production at OPECE site is VOC limited in spring. This suggests that reduction in VOCs should be a priority for reducing O3, where production and fugitive emissions from O&NG provide an attractive target. While initial reductions in NOxmight increase O3production, reduction of NOxalong with VOCs will be a necessary step to achieve long‐term ozone reduction.
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Sources of Atmospheric Volatile Organic Compounds During the Salt Lake Regional Smoke, Ozone and Aerosol Study (SAMOZA) 2022
Abstract We present measurements of volatile organic compounds (VOCs) and other trace gases taken in Salt Lake City, Utah in August and September 2022. As part of the Salt Lake regional Smoke, Ozone and Aerosol Study (SAMOZA), 35 VOCs were measured with two methods: a proton‐transfer‐reaction time‐of‐flight mass spectrometer (PTR‐ToF‐MS) and 2,4‐dinitrophenylhydrazine (DNPH) cartridges analyzed by high‐performance liquid chromatography (HPLC). Over two months, the total measured VOCs averaged 32 ± 24 ppb (mean ± standard deviation) with the hourly maximum at 141 ppb, and the total calculated OH reactivity averaged 3.7 ± 3.0 s−1(maximum at 20.7 s−1). Among them, methanol and ethanol were the most abundant VOCs, making up 42% of the ambient mixing ratio. Isoprene and monoterpenes contributed 25% of the OH reactivity from VOCs, while formaldehyde and acetaldehyde made up another 30%. The positive matrix factorization analysis showed 5 major sources of VOCs, with 32% of abundance being attributed to secondary production/biogenic sources, 44% from the combination of traffic and personal care products, 15% from industrial solvent use, and the rest from biomass burning (10%). Moderate smoke‐impacted days elevated various hazardous air pollutants (HAPs) on average by 45%–217% compared to smoke‐free days. The ratio of OH reactivity from NOxto that from VOCs showed that ozone production was mostly VOC‐limited throughout the campaign, consistent with our modeling study. VOCs and NOxboth showed increased OH reactivity due to smoke influence. NOxfeatured increased reactivity on weekdays compared to weekends, an effect not shown for VOC reactivity during SAMOZA.
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- PAR ID:
- 10572484
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Atmospheres
- Volume:
- 129
- Issue:
- 17
- ISSN:
- 2169-897X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1029/2024JD041640
