Source apportionment of gaseous Nitrophenols and their contribution to HONO formation in an urban area

Ahmed, Morshad; Rappenglueck, B.; Ganranoo, Lucksagoon; Dasgupta, Purnendu Κ.

doi:10.1016/j.chemosphere.2023.139499

Cited by 2 publications

(1 citation statement)

References 77 publications

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“…Uncertainty values for VOCs were within the range of 5% to 30%, as assigned in the studies conducted by [40,41]. In addition, 8% values were assigned for NO, NO 2 , CO and SO 2 , in alignment with earlier analyses [39].…”

Section: Pmf Methods and Error Estimationmentioning

confidence: 52%

Investigating the Complexities of VOC Sources in Mexico City in the Years 2016–2022

Alam,

Rappenglueck,

Retama

et al. 2024

Atmosphere

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Volatile organic compounds (VOCs) are major ingredients of photochemical smog. It is essential to know the spatial and temporal variation of VOC emissions. In this study, we used the Positive Matrix Factorization (PMF) model for VOC source apportionment in Mexico City. We first analyzed a data set collected during the ozone season from March–May 2016. It includes 33 VOCs, nitrogen oxide (NO), nitrogen dioxide (NO2), the sum of nitrogen oxides (NOx), carbon monoxide (CO), sulfur dioxide (SO2) and particle matter with a diameter < 1 μm (PM1). Another PMF analysis focused only on VOC data obtained in the month of May between the years 2016, 2017, 2018, 2021, and 2022 to gain insights into interannual variations. While the use of fossil fuel through combustion and evaporation continues to be major fraction in Mexico City, additional sources could be identified. Apart from biogenic sources which become more important closer to the end of the ozone season, a second natural emission factor termed “geogenic”, was identified. Overall, anthropogenic sources range between 80–90%. Diurnal plots and bivariate plots show the relative importance of these emission source factors on different temporal and spatial scales, which can be applied in emission control policies for Mexico City.

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Section: Pmf Methods and Error Estimationmentioning

confidence: 52%

Investigating the Complexities of VOC Sources in Mexico City in the Years 2016–2022

Alam,

Rappenglueck,

Retama

et al. 2024

Atmosphere

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Nitrate-Photolysis Shortens the Lifetimes of Brown Carbon Tracers from Biomass Burning

Liu,

Huang,

Lin

et al. 2024

Environ. Sci. Technol.

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Biomass burning is an important source of brown carbon (BrC) aerosols, which influence climate by affecting the Earth's radiative balance. However, the transformation pathways of BrC chromophores, especially in the presence of photochemically active species, such as nitrate, are not well understood. In this study, the nitrate-mediated aqueous-phase photooxidation of three typical BrC chromophores from biomass burning was investigated, including 4-nitrocatechol, 3-nitrosalicylic acid, and 3,4-dinitrophenol. Variations in nitrate concentrations, pH, and temperatures were systematically examined to assess their impacts on the apparent photolysis rates of these BrC chromophores. The results show that increasing nitrate concentrations significantly enhances apparent photolysis rates to 3−3.5 times compared to nitrate-free conditions. Also, a temperature rise from 0 to 30 °C increases apparent photolysis rates by a factor of 1.3−2.5 for these chromophores. However, the effect of pH varies among these chromophores, depending on the substituents and their positions on the benzene ring. High-resolution mass spectrometric analysis suggests that the photooxidation of these chromophores initiates with the addition of nitro and/or hydroxyl groups to the benzene ring, followed by a ring-opening reaction and the formation of smaller, highly oxygenated molecules including formic acid, glyoxylic acid, malonic acid, and nitropropanoic acid. This study highlights the key role of nitrate in the aqueous-phase photooxidation of BrC, altering the aging pathways and shortening the atmospheric lifetimes of BrC. These results are of particular importance for a better understanding of BrC aging and its radiative forcing, given the increase of the nitrate mass fraction in aerosols of China in recent years.

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Source apportionment of gaseous Nitrophenols and their contribution to HONO formation in an urban area

Cited by 2 publications

References 77 publications

Investigating the Complexities of VOC Sources in Mexico City in the Years 2016–2022

Investigating the Complexities of VOC Sources in Mexico City in the Years 2016–2022

Nitrate-Photolysis Shortens the Lifetimes of Brown Carbon Tracers from Biomass Burning

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