Elizabeth Asher, Rebecca S. Hornbrook, Behrooz Roozitalab, Xuan Zhang, John Ortega, Geoffrey S. Tyndall, Alan J. Hills, John J. Orlando and Eric C. Apel*,
{"title":"NSF NCAR大气模拟室中降低NOx条件下挥发性有机化合物产品分布的分析：对原位VOC测量的影响","authors":"Elizabeth Asher, Rebecca S. Hornbrook, Behrooz Roozitalab, Xuan Zhang, John Ortega, Geoffrey S. Tyndall, Alan J. Hills, John J. Orlando and Eric C. Apel*, ","doi":"10.1021/acsearthspacechem.4c00407","DOIUrl":null,"url":null,"abstract":"<p >Atmospheric oxidation of nonmethane hydrocarbons (NMHCs) under low nitrogen oxide conditions plays a critical role in the formation of oxygenated volatile organic compounds (OVOCs), yet measurements reflecting an accurate representation of these processes remain challenging. This study investigates the oxidation products of <i>n</i>-butane and 1-butene (C<sub>4</sub> oxidation) under both low and high NO<sub><i>x</i></sub> regimes and of isoprene in a low NO<sub><i>x</i></sub> regime using the NSF NCAR atmospheric simulation chamber. Measurements were obtained using the Trace Organic Gas Analyzer (TOGA) and a proton-transfer reaction mass spectrometer (PTR-MS) and compared with predictions from a box model using the Master Chemical Mechanism (MCMv3.3.1). Our results show that under low NO<sub><i>x</i></sub> conditions, C<sub>4</sub> hydroperoxides convert on the PTR-MS instrument surfaces to carbonyl artifacts, precluding an accurate picture of atmospheric composition. The PTR-MS conversion efficiencies for <i>n</i>-butane hydroperoxides, 1-butene hydroxy hydroperoxides, and ISOPOOH to carbonyl products were found to be 35 ± 1%, 67 ± 5%, and 24 ± 2%, respectively. TOGA exhibited minimal bias due to its inert internal surfaces. To further investigate surface effects, this study assessed the relative conversion of hydroperoxides to carbonyl products during analyte transmission through both stainless steel (SS) tubing and tubing treated to improve inertness (Restek Sulfinert) at different temperatures. We found that the conversion efficiency increases with temperature for hydroperoxides formed from both isoprene and C<sub>4</sub> oxidation and that the treated surface tubing is far superior to that of untreated SS in preventing these conversion reactions. These findings highlight the potential for significant error from the reported low NO<sub><i>x</i></sub> oxidation products of the many other hydrocarbons in historical VOC data sets, apart from the previously studied isoprene. Accurate quantification of OVOCs in these environments is essential for refining atmospheric models and understanding chemical cycling in the changing NO<sub><i>x</i></sub> landscape.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 7","pages":"1737–1751"},"PeriodicalIF":2.9000,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Analysis of Volatile Organic Compound Product Distributions under Reduced NOx Conditions in the NSF NCAR Atmospheric Simulation Chamber: Implications for In Situ VOC Measurements\",\"authors\":\"Elizabeth Asher, Rebecca S. Hornbrook, Behrooz Roozitalab, Xuan Zhang, John Ortega, Geoffrey S. Tyndall, Alan J. Hills, John J. Orlando and Eric C. Apel*, \",\"doi\":\"10.1021/acsearthspacechem.4c00407\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Atmospheric oxidation of nonmethane hydrocarbons (NMHCs) under low nitrogen oxide conditions plays a critical role in the formation of oxygenated volatile organic compounds (OVOCs), yet measurements reflecting an accurate representation of these processes remain challenging. This study investigates the oxidation products of <i>n</i>-butane and 1-butene (C<sub>4</sub> oxidation) under both low and high NO<sub><i>x</i></sub> regimes and of isoprene in a low NO<sub><i>x</i></sub> regime using the NSF NCAR atmospheric simulation chamber. Measurements were obtained using the Trace Organic Gas Analyzer (TOGA) and a proton-transfer reaction mass spectrometer (PTR-MS) and compared with predictions from a box model using the Master Chemical Mechanism (MCMv3.3.1). Our results show that under low NO<sub><i>x</i></sub> conditions, C<sub>4</sub> hydroperoxides convert on the PTR-MS instrument surfaces to carbonyl artifacts, precluding an accurate picture of atmospheric composition. The PTR-MS conversion efficiencies for <i>n</i>-butane hydroperoxides, 1-butene hydroxy hydroperoxides, and ISOPOOH to carbonyl products were found to be 35 ± 1%, 67 ± 5%, and 24 ± 2%, respectively. TOGA exhibited minimal bias due to its inert internal surfaces. To further investigate surface effects, this study assessed the relative conversion of hydroperoxides to carbonyl products during analyte transmission through both stainless steel (SS) tubing and tubing treated to improve inertness (Restek Sulfinert) at different temperatures. We found that the conversion efficiency increases with temperature for hydroperoxides formed from both isoprene and C<sub>4</sub> oxidation and that the treated surface tubing is far superior to that of untreated SS in preventing these conversion reactions. These findings highlight the potential for significant error from the reported low NO<sub><i>x</i></sub> oxidation products of the many other hydrocarbons in historical VOC data sets, apart from the previously studied isoprene. 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Analysis of Volatile Organic Compound Product Distributions under Reduced NOx Conditions in the NSF NCAR Atmospheric Simulation Chamber: Implications for In Situ VOC Measurements
Atmospheric oxidation of nonmethane hydrocarbons (NMHCs) under low nitrogen oxide conditions plays a critical role in the formation of oxygenated volatile organic compounds (OVOCs), yet measurements reflecting an accurate representation of these processes remain challenging. This study investigates the oxidation products of n-butane and 1-butene (C4 oxidation) under both low and high NOx regimes and of isoprene in a low NOx regime using the NSF NCAR atmospheric simulation chamber. Measurements were obtained using the Trace Organic Gas Analyzer (TOGA) and a proton-transfer reaction mass spectrometer (PTR-MS) and compared with predictions from a box model using the Master Chemical Mechanism (MCMv3.3.1). Our results show that under low NOx conditions, C4 hydroperoxides convert on the PTR-MS instrument surfaces to carbonyl artifacts, precluding an accurate picture of atmospheric composition. The PTR-MS conversion efficiencies for n-butane hydroperoxides, 1-butene hydroxy hydroperoxides, and ISOPOOH to carbonyl products were found to be 35 ± 1%, 67 ± 5%, and 24 ± 2%, respectively. TOGA exhibited minimal bias due to its inert internal surfaces. To further investigate surface effects, this study assessed the relative conversion of hydroperoxides to carbonyl products during analyte transmission through both stainless steel (SS) tubing and tubing treated to improve inertness (Restek Sulfinert) at different temperatures. We found that the conversion efficiency increases with temperature for hydroperoxides formed from both isoprene and C4 oxidation and that the treated surface tubing is far superior to that of untreated SS in preventing these conversion reactions. These findings highlight the potential for significant error from the reported low NOx oxidation products of the many other hydrocarbons in historical VOC data sets, apart from the previously studied isoprene. Accurate quantification of OVOCs in these environments is essential for refining atmospheric models and understanding chemical cycling in the changing NOx landscape.
期刊介绍：
The scope of ACS Earth and Space Chemistry includes the application of analytical, experimental and theoretical chemistry to investigate research questions relevant to the Earth and Space. The journal encompasses the highly interdisciplinary nature of research in this area, while emphasizing chemistry and chemical research tools as the unifying theme. The journal publishes broadly in the domains of high- and low-temperature geochemistry, atmospheric chemistry, marine chemistry, planetary chemistry, astrochemistry, and analytical geochemistry. ACS Earth and Space Chemistry publishes Articles, Letters, Reviews, and Features to provide flexible formats to readily communicate all aspects of research in these fields.
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