The still unexplained daytime HONO concentration in the Earth's atmosphere and the impact of water on the HONO chemistry have been a mystery for decades. Several pathways and many modeling methods have failed to reproduce the atmospheric measurements. We reveal in this study the first spectroscopic observation and characterization of the complex of HONO with water observed through its rotational signature. Under the experimental conditions, HONO-water is stable, particularly straightforward to form, and features intense absorption signals. This could explain both the influence of water on the HONO chemistry and the missing HONO sources, as well as the missing contribution of many other molecules of atmospheric relevance that skew the accuracy of field measurements and the full account of partitioning species in the atmosphere.
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http://dx.doi.org/10.1021/acs.jpclett.2c02081 | DOI Listing |
Environ Sci Technol
December 2024
State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
Reactive nitrogen (Nr) emissions significantly affect air quality and the nitrogen cycle in ecosystems. Heavy-duty diesel vehicles (HDDVs), as major sources of these emissions, exhibit complex emission characteristics because of the combined effects of different driving conditions and aftertreatment technologies. This study first investigated the emission factors (EFs) of Nr species, including NO, NO, HONO, NO, and NH, from HDDVs under different emission standards (China IV/V/VI) and cheating strategies, with a particular focus on the impact of selective catalytic reduction (SCR) systems.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China.
J Phys Chem A
October 2024
Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
As a potential source of the hydroxyl (OH) radical and nitrous acid (HONO), photolysis of -nitrophenol (ONP) is of significant interest in both experimental and theoretical studies. In the atmospheric environment, the number of water molecules surrounding ONP changes with the humidity of the air, leading to an anisotropic chemical environment. This may have an impact on the photodynamics of ONP and provide a mechanism that differs from previously reported ones in the gas phase or in solution.
View Article and Find Full Text PDFJ Phys Chem A
October 2024
Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, Zhejiang 311231, P. R. China.
Changes in atmospheric humidity affect the number of water molecules surrounding -nitrophenol (ONP), creating an anisotropic chemical environment. It, in turn, influences the photodynamic behaviors of ONP, differing from those observed in the gas phase and in solution. Recently, we explored the excited-state decay and the generation of the hydroxyl (OH) radical before proton transfer of ONP in the microsolvated environment using the MS-CASPT2//CASSCF approach.
View Article and Find Full Text PDFPNAS Nexus
September 2024
Department of Environmental Toxicology, University of California, Davis, CA 95616, USA.
Dark aqueous-phase reactions involving the nitrosation and nitration of aromatic organic compounds play a significant role in the production of light-absorbing organic carbon in the atmosphere. This process constitutes a crucial aspect of tropospheric chemistry and has attracted growing research interest, particularly in understanding the mechanisms governing nighttime reactions between phenols and nitrogen oxides. In this study, we present new findings concerning the rapid dark reactions between phenols containing electron-donating groups and inorganic nitrite in acidic aqueous solutions with pH levels <3.
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