Articles | Volume 22, issue 20
https://doi.org/10.5194/acp-22-13431-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-22-13431-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Oct 2022
Research article |
| 18 Oct 2022
| 18 Oct 2022
Quantifying the importance of vehicle ammonia emissions in an urban area of northeastern USA utilizing nitrogen isotopes
Wendell W. Walters
CORRESPONDING AUTHOR
Department of Earth, Environmental, and Planetary Sciences, Brown
University, Providence, RI 02912, USA
Institute at Brown for Environment and Society, Brown University,
Providence, RI 02912, USA
Madeline Karod
Department of Earth, Environmental, and Planetary Sciences, Brown
University, Providence, RI 02912, USA
Chemistry and Physics Department, Simmons University, Boston, MA 02215,
USA
Emma Willcocks
Program in Biology, Division of Biology and Medicine, Brown
University, Providence, RI 02912, USA
Bok H. Baek
Center for Spatial Information, Sciences, and Systems, George Mason
University, Fairfax, VA 22030, USA
Danielle E. Blum
Institute at Brown for Environment and Society, Brown University,
Providence, RI 02912, USA
Department of Chemistry, Brown University, Providence, RI 02916, USA
Meredith G. Hastings
Department of Earth, Environmental, and Planetary Sciences, Brown
University, Providence, RI 02912, USA
Institute at Brown for Environment and Society, Brown University,
Providence, RI 02912, USA
Related authors
Huan Fang and Wendell Walters
EGUsphere, https://doi.org/10.5194/egusphere-2025-923, https://doi.org/10.5194/egusphere-2025-923, 2025
Short summary
Short summary
The Sulfur Tracking Mechanism in CMAQ was used to model the oxygen isotope anomaly (Δ17O) of aerosol sulfate (ASO4) for the first time. This approach allows for a qualitative analysis of sulfate (SO42-) formation processes and comparison with corresponding measurements.
Wendell W. Walters, Masayuki Takeuchi, Danielle E. Blum, Gamze Eris, David Tanner, Weiqi Xu, Jean Rivera-Rios, Fobang Liu, Tianchang Xu, Greg Huey, Justin B. Min, Rodney Weber, Nga L. Ng, and Meredith G. Hastings
EGUsphere, https://doi.org/10.5194/egusphere-2024-3860, https://doi.org/10.5194/egusphere-2024-3860, 2024
Short summary
Short summary
We studied how chemicals released from plants and pollution interact in the atmosphere, affecting air quality and climate. By combining laboratory experiments and chemistry models, we tracked unique chemical fingerprints to understand how nitrogen compounds transform to form particles in the air. Our findings help explain the role of these reactions in pollution and provide tools to improve predictions for cleaner air and better climate policies.
Wendell W. Walters, Masayuki Takeuchi, Nga L. Ng, and Meredith G. Hastings
Geosci. Model Dev., 17, 4673–4687, https://doi.org/10.5194/gmd-17-4673-2024, https://doi.org/10.5194/gmd-17-4673-2024, 2024
Short summary
Short summary
The study introduces a novel chemical mechanism for explicitly tracking oxygen isotope transfer in oxidized reactive nitrogen and odd oxygen using the Regional Atmospheric Chemistry Mechanism, version 2. This model enhances our ability to simulate and compare oxygen isotope compositions of reactive nitrogen, revealing insights into oxidation chemistry. The approach shows promise for improving atmospheric chemistry models and tropospheric oxidation capacity predictions.
Claire Bekker, Wendell W. Walters, Lee T. Murray, and Meredith G. Hastings
Atmos. Chem. Phys., 23, 4185–4201, https://doi.org/10.5194/acp-23-4185-2023, https://doi.org/10.5194/acp-23-4185-2023, 2023
Short summary
Short summary
Nitrate is a critical component of the atmosphere that degrades air quality and ecosystem health. We have investigated the nitrogen isotope compositions of nitrate from deposition samples collected across the northeastern United States. Spatiotemporal variability in the nitrogen isotope compositions was found to track with nitrate formation chemistry. Our results highlight that nitrogen isotope compositions may be a robust tool for improving model representation of nitrate chemistry.
Heejeong Kim, Wendell W. Walters, Claire Bekker, Lee T. Murray, and Meredith G. Hastings
Atmos. Chem. Phys., 23, 4203–4219, https://doi.org/10.5194/acp-23-4203-2023, https://doi.org/10.5194/acp-23-4203-2023, 2023
Short summary
Short summary
Atmospheric nitrate has an important impact on human and ecosystem health. We evaluated atmospheric nitrate formation pathways in the northeastern US utilizing oxygen isotope compositions, which indicated a significant difference between the phases of nitrate (i.e., gas vs. particle). Comparing the observations with model simulations indicated that N2O5 hydrolysis chemistry was overpredicted. Our study has important implications for improving atmospheric chemistry model representation.
Jiajue Chai, Jack E. Dibb, Bruce E. Anderson, Claire Bekker, Danielle E. Blum, Eric Heim, Carolyn E. Jordan, Emily E. Joyce, Jackson H. Kaspari, Hannah Munro, Wendell W. Walters, and Meredith G. Hastings
Atmos. Chem. Phys., 21, 13077–13098, https://doi.org/10.5194/acp-21-13077-2021, https://doi.org/10.5194/acp-21-13077-2021, 2021
Short summary
Short summary
Nitrous acid (HONO) derived from wildfire emissions plays a key role in controlling atmospheric oxidation chemistry. However, the HONO budget remains poorly constrained. By combining the field-observed concentrations and novel isotopic composition (N and O) of HONO and nitrogen oxides (NOx), we quantitatively constrained the relative contribution of each pathway to secondary HONO production and the relative importance of major atmospheric oxidants (ozone versus peroxy) in aged wildfire smoke.
Huan Fang, Wendell W. Walters, David Mase, and Greg Michalski
Geosci. Model Dev., 14, 5001–5022, https://doi.org/10.5194/gmd-14-5001-2021, https://doi.org/10.5194/gmd-14-5001-2021, 2021
Short summary
Short summary
A new photochemical reaction scheme that incorporates nitrogen isotopes has been developed to simulate isotope tracers in air pollution. The model contains 16 N compounds, and 96 reactions involving N used in the Regional Atmospheric Chemistry Mechanism (RACM) were replicated using 15N in a new mechanism called iNRACM. The model is able to predict d15N variations in NOx, HONO, and HNO3 that are similar to those observed in aerosol and gases in the troposphere.
Wendell W. Walters, Linlin Song, Jiajue Chai, Yunting Fang, Nadia Colombi, and Meredith G. Hastings
Atmos. Chem. Phys., 20, 11551–11567, https://doi.org/10.5194/acp-20-11551-2020, https://doi.org/10.5194/acp-20-11551-2020, 2020
Short summary
Short summary
This article details new field observations of the nitrogen stable isotopic composition of ammonia emitted from vehicles conducted in the US and China. Vehicle emissions of ammonia may be a significant source to urban regions with important human health and environmental implications. Our measurements have indicated a consistent isotopic signature from vehicle ammonia emissions. The nitrogen isotopic composition of ammonia may be a useful tool for tracking vehicle emissions.
Huan Fang and Wendell Walters
EGUsphere, https://doi.org/10.5194/egusphere-2025-923, https://doi.org/10.5194/egusphere-2025-923, 2025
Short summary
Short summary
The Sulfur Tracking Mechanism in CMAQ was used to model the oxygen isotope anomaly (Δ17O) of aerosol sulfate (ASO4) for the first time. This approach allows for a qualitative analysis of sulfate (SO42-) formation processes and comparison with corresponding measurements.
Chi-Tsan Wang, Patrick C. Campbell, Paul Makar, Siqi Ma, Irena Ivanova, Bok H. Baek, Wei-Ting Hung, Zachary Moon, Youhua Tang, Barry Baker, Rick Saylor, and Daniel Tong
EGUsphere, https://doi.org/10.5194/egusphere-2025-485, https://doi.org/10.5194/egusphere-2025-485, 2025
Short summary
Short summary
Forests influence air quality by altering ozone levels, but most air pollution models overlook canopy effects. Our study improves ozone predictions by incorporating forest canopy shading and turbulence into a widely used model. We found that tree cover reduces near-surface ozone by decreasing photolysis rates and diffusion inside canopy, resulting in lower ozone concentrations in densely forested areas. These findings enhance ozone surface prediction accuracy and improve air quality modeling.
Wendell W. Walters, Masayuki Takeuchi, Danielle E. Blum, Gamze Eris, David Tanner, Weiqi Xu, Jean Rivera-Rios, Fobang Liu, Tianchang Xu, Greg Huey, Justin B. Min, Rodney Weber, Nga L. Ng, and Meredith G. Hastings
EGUsphere, https://doi.org/10.5194/egusphere-2024-3860, https://doi.org/10.5194/egusphere-2024-3860, 2024
Short summary
Short summary
We studied how chemicals released from plants and pollution interact in the atmosphere, affecting air quality and climate. By combining laboratory experiments and chemistry models, we tracked unique chemical fingerprints to understand how nitrogen compounds transform to form particles in the air. Our findings help explain the role of these reactions in pollution and provide tools to improve predictions for cleaner air and better climate policies.
Wendell W. Walters, Masayuki Takeuchi, Nga L. Ng, and Meredith G. Hastings
Geosci. Model Dev., 17, 4673–4687, https://doi.org/10.5194/gmd-17-4673-2024, https://doi.org/10.5194/gmd-17-4673-2024, 2024
Short summary
Short summary
The study introduces a novel chemical mechanism for explicitly tracking oxygen isotope transfer in oxidized reactive nitrogen and odd oxygen using the Regional Atmospheric Chemistry Mechanism, version 2. This model enhances our ability to simulate and compare oxygen isotope compositions of reactive nitrogen, revealing insights into oxidation chemistry. The approach shows promise for improving atmospheric chemistry models and tropospheric oxidation capacity predictions.
Chi-Tsan Wang, Bok H. Baek, William Vizuete, Lawrence S. Engel, Jia Xing, Jaime Green, Marc Serre, Richard Strott, Jared Bowden, and Jung-Hun Woo
Earth Syst. Sci. Data, 15, 5261–5279, https://doi.org/10.5194/essd-15-5261-2023, https://doi.org/10.5194/essd-15-5261-2023, 2023
Short summary
Short summary
Hazardous air pollutant (HAP) human exposure studies usually rely on local measurements or dispersion model methods, but those methods are limited under spatial and temporal conditions. We processed the US EPA emission data to simulate the hourly HAP emission patterns and applied the chemical transport model to simulate the HAP concentrations. The modeled HAP results exhibit good agreement (R is 0.75 and NMB is −5.6 %) with observational data.
Bok H. Baek, Carlie Coats, Siqi Ma, Chi-Tsan Wang, Yunyao Li, Jia Xing, Daniel Tong, Soontae Kim, and Jung-Hun Woo
Geosci. Model Dev., 16, 4659–4676, https://doi.org/10.5194/gmd-16-4659-2023, https://doi.org/10.5194/gmd-16-4659-2023, 2023
Short summary
Short summary
To enable the direct feedback effects of aerosols and local meteorology in an air quality modeling system without any computational bottleneck, we have developed an inline meteorology-induced emissions coupler module within the U.S. Environmental Protection Agency’s Community Multiscale Air Quality modeling system to dynamically model the complex MOtor Vehicle Emission Simulator (MOVES) on-road mobile emissions inline without a separate dedicated emissions processing model like SMOKE.
Jessica M. Burger, Emily Joyce, Meredith G. Hastings, Kurt A. M. Spence, and Katye E. Altieri
Atmos. Chem. Phys., 23, 5605–5622, https://doi.org/10.5194/acp-23-5605-2023, https://doi.org/10.5194/acp-23-5605-2023, 2023
Short summary
Short summary
A seasonal analysis of the nitrogen isotopes of atmospheric nitrate over the remote Southern Ocean reveals that similar natural NOx sources dominate in spring and summer, while winter is representative of background-level conditions. The oxygen isotopes suggest that similar oxidation pathways involving more ozone occur in spring and winter, while the hydroxyl radical is the main oxidant in summer. This work helps to constrain NOx cycling and oxidant budgets in a data-sparse remote marine region.
Claire Bekker, Wendell W. Walters, Lee T. Murray, and Meredith G. Hastings
Atmos. Chem. Phys., 23, 4185–4201, https://doi.org/10.5194/acp-23-4185-2023, https://doi.org/10.5194/acp-23-4185-2023, 2023
Short summary
Short summary
Nitrate is a critical component of the atmosphere that degrades air quality and ecosystem health. We have investigated the nitrogen isotope compositions of nitrate from deposition samples collected across the northeastern United States. Spatiotemporal variability in the nitrogen isotope compositions was found to track with nitrate formation chemistry. Our results highlight that nitrogen isotope compositions may be a robust tool for improving model representation of nitrate chemistry.
Heejeong Kim, Wendell W. Walters, Claire Bekker, Lee T. Murray, and Meredith G. Hastings
Atmos. Chem. Phys., 23, 4203–4219, https://doi.org/10.5194/acp-23-4203-2023, https://doi.org/10.5194/acp-23-4203-2023, 2023
Short summary
Short summary
Atmospheric nitrate has an important impact on human and ecosystem health. We evaluated atmospheric nitrate formation pathways in the northeastern US utilizing oxygen isotope compositions, which indicated a significant difference between the phases of nitrate (i.e., gas vs. particle). Comparing the observations with model simulations indicated that N2O5 hydrolysis chemistry was overpredicted. Our study has important implications for improving atmospheric chemistry model representation.
Bok H. Baek, Rizzieri Pedruzzi, Minwoo Park, Chi-Tsan Wang, Younha Kim, Chul-Han Song, and Jung-Hun Woo
Geosci. Model Dev., 15, 4757–4781, https://doi.org/10.5194/gmd-15-4757-2022, https://doi.org/10.5194/gmd-15-4757-2022, 2022
Short summary
Short summary
The Comprehensive Automobile Research System (CARS) is an open-source Python-based automobile emissions inventory model designed to efficiently estimate high-quality emissions. The CARS is designed to utilize the local vehicle activity database, such as vehicle travel distance, road-link-level network information, and vehicle-specific average speed by road type, to generate a temporally and spatially enhanced inventory for policymakers, stakeholders, and the air quality modeling community.
Jessica M. Burger, Julie Granger, Emily Joyce, Meredith G. Hastings, Kurt A. M. Spence, and Katye E. Altieri
Atmos. Chem. Phys., 22, 1081–1096, https://doi.org/10.5194/acp-22-1081-2022, https://doi.org/10.5194/acp-22-1081-2022, 2022
Short summary
Short summary
The nitrogen (N) isotopic composition of atmospheric nitrate in the Southern Ocean (SO) marine boundary layer (MBL) reveals the importance of oceanic alkyl nitrate emissions as a source of reactive N to the atmosphere. The oxygen isotopic composition suggests peroxy radicals contribute up to 63 % to NO oxidation and that nitrate forms via the OH pathway. This work improves our understanding of reactive N sources and cycling in a remote marine region, a proxy for the pre-industrial atmosphere.
Jiajue Chai, Jack E. Dibb, Bruce E. Anderson, Claire Bekker, Danielle E. Blum, Eric Heim, Carolyn E. Jordan, Emily E. Joyce, Jackson H. Kaspari, Hannah Munro, Wendell W. Walters, and Meredith G. Hastings
Atmos. Chem. Phys., 21, 13077–13098, https://doi.org/10.5194/acp-21-13077-2021, https://doi.org/10.5194/acp-21-13077-2021, 2021
Short summary
Short summary
Nitrous acid (HONO) derived from wildfire emissions plays a key role in controlling atmospheric oxidation chemistry. However, the HONO budget remains poorly constrained. By combining the field-observed concentrations and novel isotopic composition (N and O) of HONO and nitrogen oxides (NOx), we quantitatively constrained the relative contribution of each pathway to secondary HONO production and the relative importance of major atmospheric oxidants (ozone versus peroxy) in aged wildfire smoke.
Huan Fang, Wendell W. Walters, David Mase, and Greg Michalski
Geosci. Model Dev., 14, 5001–5022, https://doi.org/10.5194/gmd-14-5001-2021, https://doi.org/10.5194/gmd-14-5001-2021, 2021
Short summary
Short summary
A new photochemical reaction scheme that incorporates nitrogen isotopes has been developed to simulate isotope tracers in air pollution. The model contains 16 N compounds, and 96 reactions involving N used in the Regional Atmospheric Chemistry Mechanism (RACM) were replicated using 15N in a new mechanism called iNRACM. The model is able to predict d15N variations in NOx, HONO, and HNO3 that are similar to those observed in aerosol and gases in the troposphere.
Veronica R. Rollinson, Julie Granger, Sydney C. Clark, Mackenzie L. Blanusa, Claudia P. Koerting, Jamie M. P. Vaudrey, Lija A. Treibergs, Holly C. Westbrook, Catherine M. Matassa, Meredith G. Hastings, and Craig R. Tobias
Biogeosciences, 18, 3421–3444, https://doi.org/10.5194/bg-18-3421-2021, https://doi.org/10.5194/bg-18-3421-2021, 2021
Short summary
Short summary
We measured nutrients and the naturally occurring nitrogen (N) and oxygen (O) stable isotope ratios of nitrate discharged from a New England river over an annual cycle, to monitor N loading and identify dominant sources from the watershed. We uncovered a seasonality to loading and sources of N from the watershed. Seasonality in the nitrate isotope ratios also informed on N cycling, conforming to theoretical expectations of riverine nutrient cycling.
Guitao Shi, Hongmei Ma, Zhengyi Hu, Zhenlou Chen, Chunlei An, Su Jiang, Yuansheng Li, Tianming Ma, Jinhai Yu, Danhe Wang, Siyu Lu, Bo Sun, and Meredith G. Hastings
The Cryosphere, 15, 1087–1095, https://doi.org/10.5194/tc-15-1087-2021, https://doi.org/10.5194/tc-15-1087-2021, 2021
Short summary
Short summary
It is important to understand atmospheric chemistry over Antarctica under a changing climate. Thus snow collected on a traverse from the coast to Dome A was used to investigate variations in snow chemistry. The non-sea-salt fractions of K+, Mg2+, and Ca2+ are associated with terrestrial inputs, and nssCl− is from HCl. In general, proportions of non-sea-salt fractions of ions to the totals are higher in the interior areas than on the coast, and the proportions are higher in summer than in winter.
Wendell W. Walters, Linlin Song, Jiajue Chai, Yunting Fang, Nadia Colombi, and Meredith G. Hastings
Atmos. Chem. Phys., 20, 11551–11567, https://doi.org/10.5194/acp-20-11551-2020, https://doi.org/10.5194/acp-20-11551-2020, 2020
Short summary
Short summary
This article details new field observations of the nitrogen stable isotopic composition of ammonia emitted from vehicles conducted in the US and China. Vehicle emissions of ammonia may be a significant source to urban regions with important human health and environmental implications. Our measurements have indicated a consistent isotopic signature from vehicle ammonia emissions. The nitrogen isotopic composition of ammonia may be a useful tool for tracking vehicle emissions.
Erika Marín-Spiotta, Rebecca T. Barnes, Asmeret Asefaw Berhe, Meredith G. Hastings, Allison Mattheis, Blair Schneider, and Billy M. Williams
Adv. Geosci., 53, 117–127, https://doi.org/10.5194/adgeo-53-117-2020, https://doi.org/10.5194/adgeo-53-117-2020, 2020
Short summary
Short summary
The geosciences are one of the least diverse disciplines in the United States, despite the field's relevance to people's livelihoods and economies. Bias, discrimination and harassment present serious hurdles to diversifying the field. We summarize research on the factors that contribute to the persistence of hostile climates in the geosciences and other scientific disciplines and provide recommendations for cultural change through the role of mentoring networks and professional associations.
Uma Shankar, Donald McKenzie, Jeffrey P. Prestemon, Bok Haeng Baek, Mohammed Omary, Dongmei Yang, Aijun Xiu, Kevin Talgo, and William Vizuete
Atmos. Chem. Phys., 19, 15157–15181, https://doi.org/10.5194/acp-19-15157-2019, https://doi.org/10.5194/acp-19-15157-2019, 2019
Short summary
Short summary
We evaluate two wildfire emissions estimates for the southeastern US, based on projected annual areas burned in 2011–2060, against a benchmark wildfire inventory in air quality (AQ) simulations for 2010 and AQ network observations. Our emissions estimates compare well with the benchmark but all three simulations have large biases compared to observations. We find our methods suitable to assess current and future wildfire AQ impacts but also identify areas for AQ model improvements.
Jiajue Chai, David J. Miller, Eric Scheuer, Jack Dibb, Vanessa Selimovic, Robert Yokelson, Kyle J. Zarzana, Steven S. Brown, Abigail R. Koss, Carsten Warneke, and Meredith Hastings
Atmos. Meas. Tech., 12, 6303–6317, https://doi.org/10.5194/amt-12-6303-2019, https://doi.org/10.5194/amt-12-6303-2019, 2019
Short summary
Short summary
Isotopic analysis offers a potential tool to distinguish between sources and interpret transformation pathways of atmospheric species. We applied recently developed techniques in our lab to characterize the isotopic composition of reactive nitrogen species (NOx, HONO, HNO3, pNO3-) in fresh biomass burning emissions. Intercomparison with other techniques confirms the suitability of our methods, allowing for future applications of our techniques in a variety of environments.
Guitao Shi, Meredith G. Hastings, Jinhai Yu, Tianming Ma, Zhengyi Hu, Chunlei An, Chuanjin Li, Hongmei Ma, Su Jiang, and Yuansheng Li
The Cryosphere, 12, 1177–1194, https://doi.org/10.5194/tc-12-1177-2018, https://doi.org/10.5194/tc-12-1177-2018, 2018
Short summary
Short summary
The deposition and preservation of NO3− across East Antarctica was investigated. On the coast, dry deposition contributes 27–44 % of the NO3− fluxes, and the linear relationship between NO3− and snow accumulation rate suggests a homogeneity of atmospheric NO3− levels. In inland snow, a relatively weak correlation between NO3− and snow accumulation was found, indicating that NO3− is mainly dominated by post-depositional processes. The coexisting ions are generally less influential on snow NO3−.
Nathan J. Chellman, Meredith G. Hastings, and Joseph R. McConnell
The Cryosphere Discuss., https://doi.org/10.5194/tc-2016-163, https://doi.org/10.5194/tc-2016-163, 2016
Revised manuscript not accepted
Short summary
Short summary
This manuscript analyzes the changing sources of nitrate deposition to Greenland since 1760 CE using a dataset consisting of sub-seasonally resolved nitrogen isotopes of nitrate and source tracers. Correlations amongst ion concentration, source tracers, and the δ15N–NO3− provide evidence of the impact of biomass burning and fossil fuel combustion emissions of nitrogen oxides and suggest that oil combustion is the likely driver of increased nitrate concentration in Greenland ice since 1940 CE.
G. Shi, A. M. Buffen, M. G. Hastings, C. Li, H. Ma, Y. Li, B. Sun, C. An, and S. Jiang
Atmos. Chem. Phys., 15, 9435–9453, https://doi.org/10.5194/acp-15-9435-2015, https://doi.org/10.5194/acp-15-9435-2015, 2015
Short summary
Short summary
We evaluate isotopic composition of NO3- in different environments across East Antarctica. At high snow accumulation sites, isotopic ratios are suggestive of preservation of NO3- deposition. At low accumulation sites, isotopes are sensitive to both the loss of NO3- due to photolysis and secondary formation of NO3- within the snow. The imprint of post-depositional alteration is not uniform with depth, making it difficult to predict the isotopic composition at depth from near-surface data alone.
E. D. Sofen, B. Alexander, E. J. Steig, M. H. Thiemens, S. A. Kunasek, H. M. Amos, A. J. Schauer, M. G. Hastings, J. Bautista, T. L. Jackson, L. E. Vogel, J. R. McConnell, D. R. Pasteris, and E. S. Saltzman
Atmos. Chem. Phys., 14, 5749–5769, https://doi.org/10.5194/acp-14-5749-2014, https://doi.org/10.5194/acp-14-5749-2014, 2014
Related subject area
Subject: Gases | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)
Hemispheric differences in ozone across the stratosphere–troposphere exchange region
Observation and modeling of atmospheric OH and HO2∗ radicals at a subtropical rural site and implications for secondary pollutants
Tracing elevated abundance of CH2Cl2 in the subarctic upper troposphere to the Asian Summer Monsoon
Carbonyl compounds from typical combustion sources: emission characteristics, influencing factors, and their contribution to ozone formation
Formation drivers and photochemical effects of ClNO2 in a coastal city of Southeast China
Significant influence of oxygenated volatile organic compounds on atmospheric chemistry: a case study in a typical industrial city in China
Global ground-based tropospheric ozone measurements: reference data and individual site trends (2000–2022) from the TOAR-II/HEGIFTOM project
Understanding summertime H2O2 chemistry in the North China Plain through observations and modeling studies
Volatile organic compound sources and impacts in an urban Mediterranean area (Marseille, France)
Short-lived organic nitrates in a suburban temperate forest: an indication of efficient assimilation of reactive nitrogen by the biosphere?
Spatiotemporal variations in atmospheric CH4 concentrations and enhancements in northern China based on a comprehensive dataset: ground-based observations, TROPOMI data, inventory data, and inversions
Marine emissions and trade winds control the atmospheric nitrous oxide in the Galapagos Islands
Measurement report: A complex street-level air quality observation campaign in a heavy-traffic area utilizing the multivariate adaptive regression splines method for field calibration of low-cost sensors
The impact of organic nitrates on summer ozone formation in Shanghai, China
Differences in the key volatile organic compound species between their emitted and ambient concentrations in ozone formation
Tracing Ammonia Emission Sources in California's Salton Sea Region: Insights from Airborne Longwave-Infrared Hyperspectral Imaging and Ground Monitoring
Mechanistic insights into chloroacetic acid production from atmospheric multiphase volatile organic compound–chlorine chemistry
Accurate elucidation of oxidation under heavy ozone pollution: a full suite of radical measurements in the chemically complex atmosphere
Isotopic signatures of methane emission from oil and natural gas plants in southwestern China
Emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from different cumulative-mileage diesel vehicles at various ambient temperatures
Characterization of nitrous acid and its potential effects on secondary pollution in the warm season in Beijing urban areas
Vertical changes in volatile organic compounds (VOCs) and impacts on photochemical ozone formation
Airborne quantification of Angolan offshore oil and gas methane emissions
Diurnal, seasonal, and interannual variations in δ(18O) of atmospheric O2 and its application to evaluate natural and anthropogenic changes in oxygen, carbon, and water cycles
Cloud processing of dimethyl sulfide (DMS) oxidation products limits sulfur dioxide (SO2) and carbonyl sulfide (OCS) production in the eastern North Atlantic marine boundary layer
Atmospheric carbonyl compounds are crucial in regional ozone heavy pollution: insights from the Chengdu Plain Urban Agglomeration, China
Evaluating urban methane emissions and their attributes in a megacity, Osaka, Japan, via mobile and eddy covariance measurements
Tropical Ozone Trends (1998 to 2023): A Synthesis from SHADOZ, IAGOS and OMI/MLS Observations
Ozone (O3) observations in Saxony, Germany for 1997–2020: Trends, modelling and implications for O3 control
Understanding summertime peroxyacetyl nitrate (PAN) formation and its relation to aerosol pollution: insights from high-resolution measurements and modeling
Measurement report: Exploring the variations in ambient BTEX in urban Europe and their environmental health implications
Seasonal air concentration variability, gas–particle partitioning, precipitation scavenging, and air–water equilibrium of organophosphate esters in southern Canada
Measurement report: Surface exchange fluxes of HONO during the growth process of paddy fields in the Huaihe River Basin, China
Molecular and seasonal characteristics of organic vapors in urban Beijing: insights from Vocus-PTR measurements
BVOC and speciated monoterpene concentrations and fluxes at a Scandinavian boreal forest
The variations in volatile organic compounds based on the policy change for Omicron in the traffic hub of Zhengzhou
On the dynamics of ozone depletion events at Villum Research Station in the High Arctic
Measurement report: Long-term measurements of surface ozone and trends in semi-natural sub-Saharan African ecosystems
Characterization of biogenic volatile organic compounds and their oxidation products in a stressed spruce-dominated forest close to a biogas power plant
Reactive chlorine-, sulfur-, and nitrogen-containing volatile organic compounds impact atmospheric chemistry in the megacity of Delhi during both clean and extremely polluted seasons
Analysis of the day-to-day variability of ozone vertical profiles in the lower troposphere during the 2022 Paris ACROSS campaign
Ozone deposition measurements over wheat fields in the North China Plain: variability and related factors of deposition flux and velocity
Consistency evaluation of tropospheric ozone from ozonesonde and IAGOS (In-service Aircraft for a Global Observing System) observations: vertical distribution, ozonesonde types, and station–airport distance
CO2 and CO temporal variability over Mexico City from ground-based total column and surface measurements
Investigating carbonyl compounds above the Amazon rainforest using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) with NO+ chemical ionization
Measurement report: In-flight and ground-based measurements of nitrogen oxide emissions from latest-generation jet engines and 100 % sustainable aviation fuel
Measurement report: Sources, sinks, and lifetime of NOx in a suburban temperate forest at night
Measurement report: Urban ammonia and amines in Houston, Texas
Biomass-burning sources control ambient particulate matter, but traffic and industrial sources control volatile organic compound (VOC) emissions and secondary-pollutant formation during extreme pollution events in Delhi
Multi-year observations of variable incomplete combustion in the New York megacity
Rodrigo J. Seguel, Charlie Opazo, Yann Cohen, Owen R. Cooper, Laura Gallardo, Björn-Martin Sinnhuber, Florian Obersteiner, Andreas Zahn, Peter Hoor, Susanne Rohs, and Andreas Marsing
Atmos. Chem. Phys., 25, 8553–8573, https://doi.org/10.5194/acp-25-8553-2025, https://doi.org/10.5194/acp-25-8553-2025, 2025
Short summary
Short summary
We explored ozone differences between the Northern Hemisphere and Southern Hemispheres in the upper troposphere–lower stratosphere. We found lower ozone (with stratospheric origin) in the Southern Hemisphere, especially during years of severe ozone depletion. Sudden stratospheric warming events increased the ozone in each hemisphere, highlighting the relationship between stratospheric processes and ozone in the upper troposphere, where ozone is an important greenhouse gas.
Zhouxing Zou, Tianshu Chen, Qianjie Chen, Weihang Sun, Shichun Han, Zhuoyue Ren, Xinyi Li, Wei Song, Aoqi Ge, Qi Wang, Xiao Tian, Chenglei Pei, Xinming Wang, Yanli Zhang, and Tao Wang
Atmos. Chem. Phys., 25, 8147–8161, https://doi.org/10.5194/acp-25-8147-2025, https://doi.org/10.5194/acp-25-8147-2025, 2025
Short summary
Short summary
We measured ambient OH and HO2* (HO2 and contribution from RO2, organic peroxyl radicals) concentrations at a subtropical rural site and compared our observations with model results. During warm periods, the model overestimated concentrations of OH and HO2, leading to overestimation of ozone and nitric acid production. Our findings highlight the need to better understand how OH and HO2 are formed and removed, which is important for accurate air quality and climate predictions.
Markus Jesswein, Valentin Lauther, Nicolas Emig, Peter Hoor, Timo Keber, Hans-Christoph Lachnitt, Linda Ort, Tanja Schuck, Johannes Strobel, Ronja Van Luijt, C. Michael Volk, Franziska Weyland, and Andreas Engel
Atmos. Chem. Phys., 25, 8107–8126, https://doi.org/10.5194/acp-25-8107-2025, https://doi.org/10.5194/acp-25-8107-2025, 2025
Short summary
Short summary
The study investigates transport within the Asian Summer Monsoon, focusing on how CH2Cl2 reaches the subarctic tropopause region. Using data from the PHILEAS campaign in 2023, events with increased mixing ratios were detected. Their origin, the transport paths to the tropopause region, and the potential entry into the stratosphere were analyzed. The East Asian Summer Monsoon was identified as the main transport pathway, with only a small contribution to the stratosphere in the following days.
Yanjie Lu, Xinxin Feng, Yanli Feng, Minjun Jiang, Yu Peng, Tian Chen, and Yingjun Chen
Atmos. Chem. Phys., 25, 8043–8059, https://doi.org/10.5194/acp-25-8043-2025, https://doi.org/10.5194/acp-25-8043-2025, 2025
Short summary
Short summary
Through lab tests and field measurements from typical sources, we found that carbonyl compounds from biomass burning are an order of magnitude higher than those from vehicles. The formation of carbonyl compounds in solid and liquid fuel is governed by combustion temperature and emission standards, respectively. Fuel type determines the chemical composition. Biomass burning and farm machinery are key drivers of atmospheric oxidation capacity. This study provides actionable solutions to safeguard public health.
Gaojie Chen, Xiaolong Fan, Haichao Wang, Yee Jun Tham, Ziyi Lin, Xiaoting Ji, Lingling Xu, Baoye Hu, and Jinsheng Chen
Atmos. Chem. Phys., 25, 7815–7828, https://doi.org/10.5194/acp-25-7815-2025, https://doi.org/10.5194/acp-25-7815-2025, 2025
Short summary
Short summary
Our study revealed that the nighttime heterogeneous dinitrogen pentoxide (N2O5) uptake process was the major contributor of nitryl chloride (ClNO2) sources, while nitrate photolysis may promote the elevation of daytime ClNO2 concentrations. The rates of alkane oxidation by chlorine (Cl) radical in the early morning exceeded those by OH radical, significantly promoted the formation of ROx and ozone (O3), and further enhanced the atmospheric oxidation capacity levels.
Jingwen Dai, Kun Zhang, Yanli Feng, Xin Yi, Rui Li, Jin Xue, Qing Li, Lishu Shi, Jiaqiang Liao, Yanan Yi, Fangting Wang, Liumei Yang, Hui Chen, Ling Huang, Jiani Tan, Yangjun Wang, and Li Li
Atmos. Chem. Phys., 25, 7467–7484, https://doi.org/10.5194/acp-25-7467-2025, https://doi.org/10.5194/acp-25-7467-2025, 2025
Short summary
Short summary
Oxygenated volatile organic compounds (OVOCs) are important ozone (O3) precursors. However, most O3 formation analysis based on the box model (OBM) does not include any OVOC constraint. To access the interference of OVOCs with O3 simulation, this study presents results from a field campaign and OBM analysis. Our results indicate that no OVOC constraint in the OBM can lead to overestimation of OVOCs, free radicals, and O3.
Roeland Van Malderen, Anne M. Thompson, Debra E. Kollonige, Ryan M. Stauffer, Herman G. J. Smit, Eliane Maillard Barras, Corinne Vigouroux, Irina Petropavlovskikh, Thierry Leblanc, Valérie Thouret, Pawel Wolff, Peter Effertz, David W. Tarasick, Deniz Poyraz, Gérard Ancellet, Marie-Renée De Backer, Stéphanie Evan, Victoria Flood, Matthias M. Frey, James W. Hannigan, José L. Hernandez, Marco Iarlori, Bryan J. Johnson, Nicholas Jones, Rigel Kivi, Emmanuel Mahieu, Glen McConville, Katrin Müller, Tomoo Nagahama, Justus Notholt, Ankie Piters, Natalia Prats, Richard Querel, Dan Smale, Wolfgang Steinbrecht, Kimberly Strong, and Ralf Sussmann
Atmos. Chem. Phys., 25, 7187–7225, https://doi.org/10.5194/acp-25-7187-2025, https://doi.org/10.5194/acp-25-7187-2025, 2025
Short summary
Short summary
Tropospheric ozone is an important greenhouse gas and is an air pollutant. The time variability of tropospheric ozone is mainly driven by anthropogenic emissions. In this paper, we study the distribution and time variability of ozone from harmonized ground-based observations from five different measurement techniques. Our findings provide clear standard references for atmospheric models and evolving tropospheric ozone satellite data for the 2000–2022 period.
Can Ye, Pengfei Liu, Chaoyang Xue, Chenglong Zhang, Zhuobiao Ma, Chengtang Liu, Junfeng Liu, Keding Lu, Yujing Mu, and Yuanhang Zhang
Atmos. Chem. Phys., 25, 6991–7005, https://doi.org/10.5194/acp-25-6991-2025, https://doi.org/10.5194/acp-25-6991-2025, 2025
Short summary
Short summary
This study investigates H2O2 chemistry in rural North China. The observed H2O2 showed distinct diurnal variations influenced by photochemical reactions. A box model revealed that H2O2 is primarily produced by HO2 recombination and removed mainly via particle uptake. Reductions in NOx, PM2.5, and alkanes raised H2O2 levels, while cutting alkenes, aromatics, CO, and HONO lowered them. A dual strategy focusing on VOC and NOx control is essential to reduce both H2O2 and ozone pollution.
Marvin Dufresne, Thérèse Salameh, Thierry Leonardis, Grégory Gille, Alexandre Armengaud, and Stéphane Sauvage
Atmos. Chem. Phys., 25, 5977–5999, https://doi.org/10.5194/acp-25-5977-2025, https://doi.org/10.5194/acp-25-5977-2025, 2025
Short summary
Short summary
This paper discusses the 18-month-long measurement of non-methane hydrocarbons (NMHCs) in Marseille, where there was no measurement since early 2000, despite the impact of NMHCs on air quality and climate. Traffic-related sources are the largest contributor to NMHC concentrations in Marseille, and shipping strongly contributes to the formation of aerosols. Finally, the Covid-19 lockdown had an impact on NMHC concentrations, reaching a 50 % decrease for traffic-related sources.
Simone T. Andersen, Rolf Sander, Patrick Dewald, Laura Wüst, Tobias Seubert, Gunther N. T. E. Türk, Jan Schuladen, Max R. McGillen, Chaoyang Xue, Abdelwahid Mellouki, Alexandre Kukui, Vincent Michoud, Manuela Cirtog, Mathieu Cazaunau, Astrid Bauville, Hichem Bouzidi, Paola Formenti, Cyrielle Denjean, Jean-Claude Etienne, Olivier Garrouste, Christopher Cantrell, Jos Lelieveld, and John N. Crowley
Atmos. Chem. Phys., 25, 5893–5909, https://doi.org/10.5194/acp-25-5893-2025, https://doi.org/10.5194/acp-25-5893-2025, 2025
Short summary
Short summary
Measurements and modelling of reactive nitrogen gases observed in a suburban temperate forest in Rambouillet, France, circa 50 km southwest of Paris in 2022 indicate that the biosphere rapidly scavenges organic nitrates of mixed biogenic and anthropogenic origin, resulting in short lifetimes for, for example, alkyl nitrates and peroxy nitrates.
Pengfei Han, Ning Zeng, Bo Yao, Wen Zhang, Weijun Quan, Pucai Wang, Ting Wang, Minqiang Zhou, Qixiang Cai, Yuzhong Zhang, Ruosi Liang, Wanqi Sun, and Shengxiang Liu
Atmos. Chem. Phys., 25, 4965–4988, https://doi.org/10.5194/acp-25-4965-2025, https://doi.org/10.5194/acp-25-4965-2025, 2025
Short summary
Short summary
Methane (CH4) is a potent greenhouse gas. Northern China contributes a large proportion of CH4 emissions, yet large observation gaps exist. Here we compiled a comprehensive dataset, which is publicly available, that includes ground-based, satellite-based, inventory, and modeling results to show the CH4 concentrations, enhancements, and spatial–temporal variations. The data can benefit the research community and policy-makers for future observations, atmospheric inversions, and policy-making.
Timur Cinay, Dickon Young, Nazaret Narváez Jimenez, Cristina Vintimilla-Palacios, Ariel Pila Alonso, Paul B. Krummel, William Vizuete, and Andrew R. Babbin
Atmos. Chem. Phys., 25, 4703–4718, https://doi.org/10.5194/acp-25-4703-2025, https://doi.org/10.5194/acp-25-4703-2025, 2025
Short summary
Short summary
We present the initial 15 months of nitrous oxide measurements from the Galapagos Emissions Monitoring Station. The observed variability in atmospheric mole fractions during this period can be linked to several factors: seasonal variations in trade wind speed and direction across the eastern Pacific, differences in the transport history of air masses sampled, and spatiotemporal heterogeneity in regional marine nitrous oxide emissions from the coastal upwelling systems of Peru and Chile.
Petra Bauerová, Josef Keder, Adriana Šindelářová, Ondřej Vlček, William Patiño, Pavel Krč, Jan Geletič, Hynek Řezníček, Martin Bureš, Kryštof Eben, Michal Belda, Jelena Radović, Vladimír Fuka, Radek Jareš, Igor Esau, and Jaroslav Resler
Atmos. Chem. Phys., 25, 4477–4504, https://doi.org/10.5194/acp-25-4477-2025, https://doi.org/10.5194/acp-25-4477-2025, 2025
Short summary
Short summary
The study explored urban air quality in Prague using low-cost sensors and highlighted the multivariate adaptive regression splines (MARS) correction method's effectiveness in enhancing accuracy. Results showed traffic's impact on nitrogen dioxide levels and atmospheric dynamics on particulate matter. The research confirmed MARS-corrected sensors as cost-effective for monitoring, despite challenges like sensor ageing and data quality control.
Chunmeng Li, Xiaorui Chen, Haichao Wang, Tianyu Zhai, Xuefei Ma, Xinping Yang, Shiyi Chen, Min Zhou, Shengrong Lou, Xin Li, Limin Zeng, and Keding Lu
Atmos. Chem. Phys., 25, 3905–3918, https://doi.org/10.5194/acp-25-3905-2025, https://doi.org/10.5194/acp-25-3905-2025, 2025
Short summary
Short summary
This study reports an observation of organic nitrate (including total peroxy nitrates and total alkyl nitrates) in Shanghai, China, during the summer of 2021, by homemade thermal dissociation cavity-enhanced absorption spectroscopy (TD-CEAS; Atmos. Meas. Tech., 14, 4033–4051, 2021). The distribution of organic nitrates and their effects on local ozone production are analyzed based on field observations in conjunction with model simulations.
Xudong Zheng and Shaodong Xie
Atmos. Chem. Phys., 25, 3807–3820, https://doi.org/10.5194/acp-25-3807-2025, https://doi.org/10.5194/acp-25-3807-2025, 2025
Short summary
Short summary
To reduce uncertainties in identifying the key volatile organic compounds (VOCs) in ozone (O3) formation from ambient concentrations, this study comprehensively calculates the emitted VOC concentrations during both nighttime and daytime using the nitrate radical, O3, and hydroxyl radical reaction rates and ambient VOC concentrations. Based on the emitted concentrations, isoprene is one of the top three species contributing to O3 formation, which may be overlooked in observed concentrations.
Sina Hasheminassab, David M. Tratt, Olga V. Kalashnikova, Clement S. Chang, Morad Alvarez, Kerry N. Buckland, Michael J. Garay, Francesca M. Hopkins, Eric R. Keim, Le Kuai, Yaning Miao, Payam Pakbin, William C. Porter, and Mohammad H. Sowlat
EGUsphere, https://doi.org/10.5194/egusphere-2025-1378, https://doi.org/10.5194/egusphere-2025-1378, 2025
Short summary
Short summary
Ammonia (NH3) is a key air pollutant linked to fine particle pollution, yet its sources remain poorly understood. Using airborne infrared imaging and ground sensors, we mapped NH3 emissions in California’s Salton Sea region with unprecedented detail. We found high emissions from farms, geothermal plants, and waste sites, including sources missing from inventories. These findings highlight the need for better NH3 monitoring to improve air quality models and guide pollution reduction strategies.
Mingxue Li, Men Xia, Chunshui Lin, Yifan Jiang, Weihang Sun, Yurun Wang, Yingnan Zhang, Maoxia He, and Tao Wang
Atmos. Chem. Phys., 25, 3753–3764, https://doi.org/10.5194/acp-25-3753-2025, https://doi.org/10.5194/acp-25-3753-2025, 2025
Short summary
Short summary
Our field campaigns observed a strong diel pattern of chloroacetic acid as well as a strong correlation between its level and that of reactive chlorine species at a coastal site. Using quantum chemical calculations and box model simulation with an updated Master Chemical Mechanism, we found that the formation pathway of chloroacetic acid involved multiphase processes. Our study enhances understanding of atmospheric organic chlorine chemistry and emphasizes the importance of multiphase reactions.
Renzhi Hu, Guoxian Zhang, Haotian Cai, Jingyi Guo, Keding Lu, Xin Li, Shengrong Lou, Zhaofeng Tan, Changjin Hu, Pinhua Xie, and Wenqing Liu
Atmos. Chem. Phys., 25, 3011–3028, https://doi.org/10.5194/acp-25-3011-2025, https://doi.org/10.5194/acp-25-3011-2025, 2025
Short summary
Short summary
A full suite of radical measurements (OH, HO2, RO2, and kOH) was established to accurately elucidate the limitations of oxidation in a chemically complex atmosphere. Sensitivity tests revealed that the incorporation of complex processes enabled a balance in both radical concentrations and coordinate ratios, effectively addressing the deficiency in the ozone generation mechanism. The full-chain radical detection bridged the gap between the photochemistry and the intensive oxidation level.
Dingxi Chen, Yi Liu, Zetong Niu, Ao Wang, Pius Otwil, Yuanyuan Huang, Zhongcong Sun, Xiaobing Pang, Liyang Zhan, and Longfei Yu
EGUsphere, https://doi.org/10.5194/egusphere-2025-377, https://doi.org/10.5194/egusphere-2025-377, 2025
Short summary
Short summary
We carried out studies at 11 oil and gas sites in Southwest China (an important natural gas production area), investigating the methane concentration distribution pattern and emission inventory of oil and gas industrial sites through a combination of ground monitoring and drone airborne monitoring techniques, and at the same time, utilizing stable isotope techniques to trace back the methane from the oil and gas sites.
Shuwen Guo, Xuan Zheng, Xiao He, Lewei Zeng, Liqiang He, Xian Wu, Yifei Dai, Zihao Huang, Ting Chen, Shupei Xiao, Yan You, Sheng Xiang, Shaojun Zhang, Jingkun Jiang, and Ye Wu
Atmos. Chem. Phys., 25, 2695–2705, https://doi.org/10.5194/acp-25-2695-2025, https://doi.org/10.5194/acp-25-2695-2025, 2025
Short summary
Short summary
We considered two potential influencing factors of heavy-duty diesel vehicle emissions that are rarely mentioned in the literature: cumulative mileage and ambient temperatures. The results suggest that prolonged use of heavy-duty diesel vehicles and low ambient temperatures leads to reduced engine combustion efficiency, which in turn increases tailpipe emissions significantly.
Junling Li, Chaofan Lian, Mingyuan Liu, Hao Zhang, Yongxin Yan, Yufei Song, Chun Chen, Jiaqi Wang, Haijie Zhang, Yanqin Ren, Yucong Guo, Weigang Wang, Yisheng Xu, Hong Li, Jian Gao, and Maofa Ge
Atmos. Chem. Phys., 25, 2551–2568, https://doi.org/10.5194/acp-25-2551-2025, https://doi.org/10.5194/acp-25-2551-2025, 2025
Short summary
Short summary
As a key source of hydroxyl (OH) radical, nitrous acid (HONO) has attracted much attention for its important role in the atmospheric oxidant capacity (AOC) increase. In this study, we made a comparison of the ambient levels, variation patterns, sources, and formation pathway in the warm season on the basis of continuous intensive observations at an urban site of Beijing. This work highlights the importance of HONO for the AOC in the warm season.
Xiao-Bing Li, Bin Yuan, Yibo Huangfu, Suxia Yang, Xin Song, Jipeng Qi, Xianjun He, Sihang Wang, Yubin Chen, Qing Yang, Yongxin Song, Yuwen Peng, Guiqian Tang, Jian Gao, Dasa Gu, and Min Shao
Atmos. Chem. Phys., 25, 2459–2472, https://doi.org/10.5194/acp-25-2459-2025, https://doi.org/10.5194/acp-25-2459-2025, 2025
Short summary
Short summary
Online vertical gradient measurements of volatile organic compounds (VOCs), ozone, and NOx were conducted based on a 325 m tall tower in urban Beijing. Vertical changes in the concentrations, compositions, key drivers, and environmental impacts of VOCs were analyzed in this study. We find that VOC species display differentiated vertical variation patterns and distinct roles in contributing to photochemical ozone formation with increasing height in the urban planetary boundary layer.
Alina Fiehn, Maximilian Eckl, Magdalena Pühl, Tiziana Bräuer, Klaus-Dirk Gottschaldt, Heinfried Aufmhoff, Lisa Eirenschmalz, Gregor Neumann, Felicitas Sakellariou, Daniel Sauer, Robert Baumann, Guilherme De Aguiar Ventura, Winne Nayole Cadete, Dário Luciano Zua, Manuel Xavier, Paulo Correia, and Anke Roiger
EGUsphere, https://doi.org/10.5194/egusphere-2025-635, https://doi.org/10.5194/egusphere-2025-635, 2025
Short summary
Short summary
In September 2022, the METHANE-To-Go Africa (MTGA) campaign, part of UNEP’s IMEO Methane Science Studies, conducted the first CH₄ emissions measurements from West Africa’s offshore oil and gas sector. Using an aircraft-based mass balance method, emissions from Angolan offshore facilities were quantified. Older, low-producing facilities showed higher emissions than newer ones. High-emission events were observed, highlighting the need for targeted monitoring and mitigation efforts.
Shigeyuki Ishidoya, Satoshi Sugawara, and Atsushi Okazaki
Atmos. Chem. Phys., 25, 1965–1987, https://doi.org/10.5194/acp-25-1965-2025, https://doi.org/10.5194/acp-25-1965-2025, 2025
Short summary
Short summary
The 18O/16O ratio of atmospheric oxygen, δatm(18O), is higher than that of ocean water due to isotopic effects during biospheric activities. This is known as the Dole–Morita effect, and its millennial-scale variations are recorded in ice cores. However, small variations of δatm(18O) in the present day have never been detected so far. This paper presents the first observations of diurnal, seasonal, and secular variations in δatm(18O) and applies them to evaluate oxygen, carbon, and water cycles.
Delaney B. Kilgour, Christopher M. Jernigan, Olga Garmash, Sneha Aggarwal, Shengqian Zhou, Claudia Mohr, Matt E. Salter, Joel A. Thornton, Jian Wang, Paul Zieger, and Timothy H. Bertram
Atmos. Chem. Phys., 25, 1931–1947, https://doi.org/10.5194/acp-25-1931-2025, https://doi.org/10.5194/acp-25-1931-2025, 2025
Short summary
Short summary
We report simultaneous measurements of dimethyl sulfide (DMS) and hydroperoxymethyl thioformate (HPMTF) in the eastern North Atlantic. We use an observationally constrained box model to show that cloud loss is the dominant sink of HPMTF in this region over 6 weeks, resulting in large reductions in DMS-derived products that contribute to aerosol formation and growth. Our findings indicate that fast cloud processing of HPMTF must be included in global models to accurately capture the sulfur cycle.
Jiemeng Bao, Xin Zhang, Zhenhai Wu, Li Zhou, Jun Qian, Qinwen Tan, Fumo Yang, Junhui Chen, Yunfeng Li, Hefan Liu, Liqun Deng, and Hong Li
Atmos. Chem. Phys., 25, 1899–1916, https://doi.org/10.5194/acp-25-1899-2025, https://doi.org/10.5194/acp-25-1899-2025, 2025
Short summary
Short summary
We studied carbonyl compounds' role in ozone pollution in the Chengdu Plain Urban Agglomeration, China. During heavy pollution in August 2019, we measured carbonyls at nine sites and analyzed their impact. Areas with higher carbonyl levels, like Chengdu, had worse ozone pollution. While their abundance matters, chemical reactions with other pollutants are the main drivers. Our findings show regional cooperation is vital to reducing ozone pollution effectively.
Masahito Ueyama, Taku Umezawa, Yukio Terao, Mark Lunt, and James Lawrence France
EGUsphere, https://doi.org/10.5194/egusphere-2024-3926, https://doi.org/10.5194/egusphere-2024-3926, 2025
Short summary
Short summary
Methane (CH4) emissions were measured in Megacity Osaka, Japan, using mobile and eddy covariance methods. The CH4 emissions were much higher than those reported in local inventories, with natural gas contributing up to 74 % of the emissions. Several CH4 sources not accounted for in current inventories were identified. These results emphasize the need for more comprehensive emissions tracking in urban areas to enhance climate change mitigation efforts.
Anne M. Thompson, Ryan M. Stauffer, Debra E. Kollonige, Jerald R. Ziemke, Maria Cazorla, Pawel Wolff, and Bastien Sauvage
EGUsphere, https://doi.org/10.5194/egusphere-2024-3761, https://doi.org/10.5194/egusphere-2024-3761, 2025
Short summary
Short summary
This paper uses tropical ozone profiles from balloon borne instruments and aircraft to show that ozone in the free troposphere is not growing fast except over equatorial SE Asia.
Yaru Wang, Dominik van Pinxteren, Andreas Tilgner, Erik Hans Hoffmann, Max Hell, Susanne Bastian, and Hartmut Herrmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-4202, https://doi.org/10.5194/egusphere-2024-4202, 2025
Short summary
Short summary
Tropospheric ground-level ozone (O3) is a global air-quality pollutant and greenhouse gas. Long-term O3 trends from 16 stations in Saxony, Germany, were compared over three periods, revealing worsened O3 pollution over the last decade. O3 formation has been volatile organic compound (VOC)-limited at traffic and urban sites for the past 20 years. To mitigate O3 pollution, moderate nitrogen oxides and additional VOC controls, particularly in solvent use, should be prioritized in the coming years.
Baoye Hu, Naihua Chen, Rui Li, Mingqiang Huang, Jinsheng Chen, Youwei Hong, Lingling Xu, Xiaolong Fan, Mengren Li, Lei Tong, Qiuping Zheng, and Yuxiang Yang
Atmos. Chem. Phys., 25, 905–921, https://doi.org/10.5194/acp-25-905-2025, https://doi.org/10.5194/acp-25-905-2025, 2025
Short summary
Short summary
Box modeling with the Master Chemical Mechanism (MCM) was used to explore summertime peroxyacetyl nitrate (PAN) formation and its link to aerosol pollution under high-ozone conditions. The MCM model is effective in the study of PAN photochemical formation and performed better during the clean period than the haze period. Machine learning analysis identified ammonia, nitrate, and fine particulate matter as the top three factors contributing to simulation bias.
Xiansheng Liu, Xun Zhang, Marvin Dufresne, Tao Wang, Lijie Wu, Rosa Lara, Roger Seco, Marta Monge, Ana Maria Yáñez-Serrano, Marie Gohy, Paul Petit, Audrey Chevalier, Marie-Pierre Vagnot, Yann Fortier, Alexia Baudic, Véronique Ghersi, Grégory Gille, Ludovic Lanzi, Valérie Gros, Leïla Simon, Heidi Héllen, Stefan Reimann, Zoé Le Bras, Michelle Jessy Müller, David Beddows, Siqi Hou, Zongbo Shi, Roy M. Harrison, William Bloss, James Dernie, Stéphane Sauvage, Philip K. Hopke, Xiaoli Duan, Taicheng An, Alastair C. Lewis, James R. Hopkins, Eleni Liakakou, Nikolaos Mihalopoulos, Xiaohu Zhang, Andrés Alastuey, Xavier Querol, and Thérèse Salameh
Atmos. Chem. Phys., 25, 625–638, https://doi.org/10.5194/acp-25-625-2025, https://doi.org/10.5194/acp-25-625-2025, 2025
Short summary
Short summary
This study examines BTEX (benzene, toluene, ethylbenzene, xylenes) pollution in urban areas across seven European countries. Analyzing data from 22 monitoring sites, we found traffic and industrial activities significantly impact BTEX levels, with peaks during rush hours. The risk from BTEX exposure remains moderate, especially in high-traffic and industrial zones, highlighting the need for targeted air quality management to protect public health and improve urban air quality.
Yuening Li, Faqiang Zhan, Chubashini Shunthirasingham, Ying Duan Lei, Jenny Oh, Amina Ben Chaaben, Zhe Lu, Kelsey Lee, Frank A. P. C. Gobas, Hayley Hung, and Frank Wania
Atmos. Chem. Phys., 25, 459–472, https://doi.org/10.5194/acp-25-459-2025, https://doi.org/10.5194/acp-25-459-2025, 2025
Short summary
Short summary
Organophosphate esters are important humanmade trace contaminants. Measuring them in the atmospheric gas phase, particles, precipitation, and surface water in Canada, we explore seasonal concentration variability, gas–particle partitioning, precipitation scavenging, and the air–water equilibrium. Whereas higher summer concentrations and efficient precipitation scavenging conform with expectations, the lack of a relationship between compound volatility and gas–particle partitioning is puzzling.
Fanhao Meng, Baobin Han, Min Qin, Wu Fang, Ke Tang, Dou Shao, Zhitang Liao, Jun Duan, Yan Feng, Yong Huang, Ting Ni, and Pinhua Xie
Atmos. Chem. Phys., 24, 14191–14208, https://doi.org/10.5194/acp-24-14191-2024, https://doi.org/10.5194/acp-24-14191-2024, 2024
Short summary
Short summary
Comprehensive observations of HONO and NOx fluxes were conducted over paddy fields in the Huaihe River Basin. Consecutive peaks in HONO and NO fluxes suggest a potentially enhanced release of HONO and NO due to soil tillage, whereas waterlogged soil may inhibit microbial nitrification processes following irrigation. Notably, biological processes and light-driven NO2 reactions at the surface may serve as sources of HONO and influence the local HONO budget during rotary tillage.
Zhaojin An, Rujing Yin, Xinyan Zhao, Xiaoxiao Li, Yuyang Li, Yi Yuan, Junchen Guo, Yiqi Zhao, Xue Li, Dandan Li, Yaowei Li, Dongbin Wang, Chao Yan, Kebin He, Douglas R. Worsnop, Frank N. Keutsch, and Jingkun Jiang
Atmos. Chem. Phys., 24, 13793–13810, https://doi.org/10.5194/acp-24-13793-2024, https://doi.org/10.5194/acp-24-13793-2024, 2024
Short summary
Short summary
Online Vocus-PTR measurements show the compositions and seasonal variations in organic vapors in urban Beijing. With enhanced sensitivity and mass resolution, various species at a level of sub-parts per trillion (ppt) and organics with multiple oxygens (≥ 3) were observed. The fast photooxidation process in summer leads to an increase in both concentration and proportion of organics with multiple oxygens, while, in other seasons, the variations in them could be influenced by mixed sources.
Ross Charles Petersen, Thomas Holst, Cheng Wu, Radovan Krejci, Jeremy Chan, Claudia Mohr, and Janne Rinne
EGUsphere, https://doi.org/10.5194/egusphere-2024-3410, https://doi.org/10.5194/egusphere-2024-3410, 2024
Short summary
Short summary
Ecosystem-scale emissions of biogenic volatile organic compounds (BVOCs) are important for atmospheric chemistry. Here we investigate boreal BVOC fluxes from a forest in central Sweden. BVOC fluxes were measured above-canopy using proton-transfer-reaction mass spectrometry, while compound-specific monoterpene (MT) fluxes were assessed using a concentration gradient method. We also evaluate the impact of chemical degradation on observed sesquiterpene (SQT) and nighttime MT fluxes.
Bowen Zhang, Dong Zhang, Zhe Dong, Xinshuai Song, Ruiqin Zhang, and Xiao Li
Atmos. Chem. Phys., 24, 13587–13601, https://doi.org/10.5194/acp-24-13587-2024, https://doi.org/10.5194/acp-24-13587-2024, 2024
Short summary
Short summary
To gain insight into the impact of changes due to epidemic control policies, we undertook continuous online monitoring of volatile organic compounds (VOCs) at an urban site in Zhengzhou over a 2-month period. This study examines the characteristics of VOCs, their sources, and their temporal evolution. It also assesses the impact of the policy change on VOC pollution during the monitoring period, thus providing a basis for further research on VOC pollution and source control.
Jakob Boyd Pernov, Jens Liengaard Hjorth, Lise Lotte Sørensen, and Henrik Skov
Atmos. Chem. Phys., 24, 13603–13631, https://doi.org/10.5194/acp-24-13603-2024, https://doi.org/10.5194/acp-24-13603-2024, 2024
Short summary
Short summary
Arctic ozone depletion events (ODEs) occur every spring and have vast implications for the oxidizing capacity, radiative balance, and mercury oxidation. In this study, we analyze ozone, ODEs, and their connection to meteorological and air mass history variables through statistical analyses, back trajectories, and machine learning (ML) at Villum Research Station. ODEs are favorable under sunny, calm conditions with air masses arriving from northerly wind directions with sea ice contact.
Hagninou Elagnon Venance Donnou, Aristide Barthélémy Akpo, Money Ossohou, Claire Delon, Véronique Yoboué, Dungall Laouali, Marie Ouafo-Leumbe, Pieter Gideon Van Zyl, Ousmane Ndiaye, Eric Gardrat, Maria Dias-Alves, and Corinne Galy-Lacaux
Atmos. Chem. Phys., 24, 13151–13182, https://doi.org/10.5194/acp-24-13151-2024, https://doi.org/10.5194/acp-24-13151-2024, 2024
Short summary
Short summary
Ozone is a secondary air pollutant that is detrimental to human and plant health. A better understanding of its chemical evolution is a challenge for Africa, where it is still undersampled. Out of 14 sites examined (1995–2020), high levels of O3 are reported in southern Africa. The dominant chemical processes leading to O3 formation are identified. A decrease in O3 is observed at Katibougou (Mali) and Banizoumbou (Niger), and an increase is found at Zoétélé (Cameroon) and Skukuza (South Africa).
Junwei Song, Georgios I. Gkatzelis, Ralf Tillmann, Nicolas Brüggemann, Thomas Leisner, and Harald Saathoff
Atmos. Chem. Phys., 24, 13199–13217, https://doi.org/10.5194/acp-24-13199-2024, https://doi.org/10.5194/acp-24-13199-2024, 2024
Short summary
Short summary
Biogenic volatile organic compounds (BVOCs) and organic aerosol (OA) particles were measured online in a stressed spruce-dominated forest. OA was mainly attributed to the monoterpene oxidation products. The mixing ratios of BVOCs were higher than the values previously measured in other temperate forests. The results demonstrate that BVOCs are influenced not only by meteorology and biogenic emissions but also by local anthropogenic emissions and subsequent chemical transformation processes.
Sachin Mishra, Vinayak Sinha, Haseeb Hakkim, Arpit Awasthi, Sachin D. Ghude, Vijay Kumar Soni, Narendra Nigam, Baerbel Sinha, and Madhavan N. Rajeevan
Atmos. Chem. Phys., 24, 13129–13150, https://doi.org/10.5194/acp-24-13129-2024, https://doi.org/10.5194/acp-24-13129-2024, 2024
Short summary
Short summary
We quantified 111 gases using mass spectrometry to understand how seasonal and emission changes lead from clean air in the monsoon season to extremely polluted air in the post-monsoon season in Delhi. Averaged total mass concentrations (260 µg m-3) were > 4 times in polluted periods, driven by biomass burning emissions and reduced atmospheric ventilation. Reactive gaseous nitrogen, chlorine, and sulfur compounds hitherto unreported from such a polluted environment were discovered.
Gérard Ancellet, Camille Viatte, Anne Boynard, François Ravetta, Jacques Pelon, Cristelle Cailteau-Fischbach, Pascal Genau, Julie Capo, Axel Roy, and Philippe Nédélec
Atmos. Chem. Phys., 24, 12963–12983, https://doi.org/10.5194/acp-24-12963-2024, https://doi.org/10.5194/acp-24-12963-2024, 2024
Short summary
Short summary
Characterization of ozone pollution in urban areas benefited from a measurement campaign in summer 2022 in the Paris region. The analysis is based on 21 d of lidar and aircraft observations. The main objective is an analysis of the sensitivity of ozone pollution to the micrometeorological processes in the urban atmospheric boundary layer and the transport of regional pollution. The paper also discusses to what extent satellite observations can track observed ozone plumes.
Xiaoyi Zhang, Wanyun Xu, Weili Lin, Gen Zhang, Jinjian Geng, Li Zhou, Huarong Zhao, Sanxue Ren, Guangsheng Zhou, Jianmin Chen, and Xiaobin Xu
Atmos. Chem. Phys., 24, 12323–12340, https://doi.org/10.5194/acp-24-12323-2024, https://doi.org/10.5194/acp-24-12323-2024, 2024
Short summary
Short summary
Ozone (O3) deposition is a key process that removes surface O3, affecting air quality, ecosystems and climate change. We conducted O3 deposition measurement over a wheat canopy using a newly relaxed eddy accumulation flux system. Large variabilities in O3 deposition were detected, mainly determined by crop growth and modulated by various environmental factors. More O3 deposition observations over different surfaces are needed for exploring deposition mechanisms and model optimization.
Honglei Wang, David W. Tarasick, Jane Liu, Herman G. J. Smit, Roeland Van Malderen, Lijuan Shen, Romain Blot, and Tianliang Zhao
Atmos. Chem. Phys., 24, 11927–11942, https://doi.org/10.5194/acp-24-11927-2024, https://doi.org/10.5194/acp-24-11927-2024, 2024
Short summary
Short summary
In this study, we identify 23 suitable pairs of sites from World Ozone and Ultraviolet Radiation Data Centre (WOUDC) and In-service Aircraft for a Global Observing System (IAGOS) datasets (1995 to 2021), compare the average vertical distributions of tropospheric O3 from ozonesonde and aircraft measurements, and analyze the differences based on ozonesonde type and station–airport distance.
Noémie Taquet, Wolfgang Stremme, María Eugenia González del Castillo, Victor Almanza, Alejandro Bezanilla, Olivier Laurent, Carlos Alberti, Frank Hase, Michel Ramonet, Thomas Lauvaux, Ke Che, and Michel Grutter
Atmos. Chem. Phys., 24, 11823–11848, https://doi.org/10.5194/acp-24-11823-2024, https://doi.org/10.5194/acp-24-11823-2024, 2024
Short summary
Short summary
We characterize the variability in CO and CO2 emissions over Mexico City from long-term time-resolved Fourier transform infrared spectroscopy solar absorption and surface measurements from 2013 to 2021. Using the average intraday CO growth rate from total columns, the average CO / CO2 ratio and TROPOMI data, we estimate the interannual variability in the CO and CO2 anthropogenic emissions of Mexico City, highlighting the effect of an unprecedented drop in activity due to the COVID-19 lockdown.
Akima Ringsdorf, Achim Edtbauer, Bruna Holanda, Christopher Poehlker, Marta O. Sá, Alessandro Araújo, Jürgen Kesselmeier, Jos Lelieveld, and Jonathan Williams
Atmos. Chem. Phys., 24, 11883–11910, https://doi.org/10.5194/acp-24-11883-2024, https://doi.org/10.5194/acp-24-11883-2024, 2024
Short summary
Short summary
We show the average height distribution of separately observed aldehydes and ketones over a day and discuss their rainforest-specific sources and sinks as well as their seasonal changes above the Amazon. Ketones have much longer atmospheric lifetimes than aldehydes and thus different implications for atmospheric chemistry. However, they are commonly observed together, which we overcome by measuring with a NO+ chemical ionization mass spectrometer for the first time in the Amazon rainforest.
Theresa Harlass, Rebecca Dischl, Stefan Kaufmann, Raphael Märkl, Daniel Sauer, Monika Scheibe, Paul Stock, Tiziana Bräuer, Andreas Dörnbrack, Anke Roiger, Hans Schlager, Ulrich Schumann, Magdalena Pühl, Tobias Schripp, Tobias Grein, Linda Bondorf, Charles Renard, Maxime Gauthier, Mark Johnson, Darren Luff, Paul Madden, Peter Swann, Denise Ahrens, Reetu Sallinen, and Christiane Voigt
Atmos. Chem. Phys., 24, 11807–11822, https://doi.org/10.5194/acp-24-11807-2024, https://doi.org/10.5194/acp-24-11807-2024, 2024
Short summary
Short summary
Emissions from aircraft have a direct impact on our climate. Here, we present airborne and ground-based measurement data of nitrogen oxides that were collected in the exhaust of an Airbus aircraft. We study the impact of burning fossil and sustainable aviation fuel on nitrogen oxide emissions at different engine settings related to combustor temperature, pressure and fuel flow. Further, we compare observations with engine emission models.
Simone T. Andersen, Max R. McGillen, Chaoyang Xue, Tobias Seubert, Patrick Dewald, Gunther N. T. E. Türk, Jan Schuladen, Cyrielle Denjean, Jean-Claude Etienne, Olivier Garrouste, Marina Jamar, Sergio Harb, Manuela Cirtog, Vincent Michoud, Mathieu Cazaunau, Antonin Bergé, Christopher Cantrell, Sebastien Dusanter, Bénédicte Picquet-Varrault, Alexandre Kukui, Abdelwahid Mellouki, Lucy J. Carpenter, Jos Lelieveld, and John N. Crowley
Atmos. Chem. Phys., 24, 11603–11618, https://doi.org/10.5194/acp-24-11603-2024, https://doi.org/10.5194/acp-24-11603-2024, 2024
Short summary
Short summary
Using measurements of various trace gases in a suburban forest near Paris in the summer of 2022, we were able to gain insight into the sources and sinks of NOx (NO+NO2) with a special focus on their nighttime chemical and physical loss processes. NO was observed as a result of nighttime soil emissions when O3 levels were strongly depleted by deposition. NO oxidation products were not observed at night, indicating that soil and/or foliar surfaces are an efficient sink of reactive N.
Lee Tiszenkel, James H. Flynn, and Shan-Hu Lee
Atmos. Chem. Phys., 24, 11351–11363, https://doi.org/10.5194/acp-24-11351-2024, https://doi.org/10.5194/acp-24-11351-2024, 2024
Short summary
Short summary
Ammonia and amines are important ingredients for aerosol formation in urban environments, but the measurements of these compounds are extremely challenging. Our observations show that urban ammonia and amines in Houston are emitted from urban sources, and diurnal variations in their concentrations are likely governed by gas-to-particle conversion and emissions.
Arpit Awasthi, Baerbel Sinha, Haseeb Hakkim, Sachin Mishra, Varkrishna Mummidivarapu, Gurmanjot Singh, Sachin D. Ghude, Vijay Kumar Soni, Narendra Nigam, Vinayak Sinha, and Madhavan N. Rajeevan
Atmos. Chem. Phys., 24, 10279–10304, https://doi.org/10.5194/acp-24-10279-2024, https://doi.org/10.5194/acp-24-10279-2024, 2024
Short summary
Short summary
We use 111 volatile organic compounds (VOCs), PM10, and PM2.5 in a positive matrix factorization (PMF) model to resolve 11 pollution sources validated with chemical fingerprints. Crop residue burning and heating account for ~ 50 % of the PM, while traffic and industrial emissions dominate the gas-phase VOC burden and formation potential of secondary organic aerosols (> 60 %). Non-tailpipe emissions from compressed-natural-gas-fuelled commercial vehicles dominate the transport sector's PM burden.
Luke D. Schiferl, Cong Cao, Bronte Dalton, Andrew Hallward-Driemeier, Ricardo Toledo-Crow, and Róisín Commane
Atmos. Chem. Phys., 24, 10129–10142, https://doi.org/10.5194/acp-24-10129-2024, https://doi.org/10.5194/acp-24-10129-2024, 2024
Short summary
Short summary
Carbon monoxide (CO) is an air pollutant and an important indicator of the incomplete combustion of fossil fuels in cities. Using 4 years of winter and spring observations in New York City, we found that both the magnitude and variability of CO from the metropolitan area are greater than expected. Transportation emissions cannot explain the missing and variable CO, which points to energy from buildings as a likely underappreciated source of urban air pollution and greenhouse gas emissions.
Cited articles
Ampollini, L., Katz, E. F., Bourne, S., Tian, Y., Novoselac, A., Goldstein,
A. H., Lucic, G., Waring, M. S., and DeCarlo, P. F.: Observations and
Contributions of Real-Time Indoor Ammonia Concentrations during HOMEChem,
Environ. Sci. Technol., 53, 8591–8598,
https://doi.org/10.1021/acs.est.9b02157, 2019.
Ashbaugh, L. L. and Eldred, R. A.: Loss of particle nitrate from teflon
sampling filters: effects on measured gravimetric mass in California and in
the IMPROVE network, J. Air Waste Manage., 54, 93–104,
https://doi.org/10.1080/10473289.2004.10470878, 2004.
Baek, B. H. and Seppanen, C.: CEMPD/SMOKE: SMOKE v4.8.1 Public Release
(January 29, 2021), Zenodo, https://doi.org/10.5281/zenodo.4480334, 2021.
Begum, B. A., Kim, E., Jeong, C.-H., Lee, D.-W., and Hopke, P. K.:
Evaluation of the potential source contribution function using the 2002
Quebec forest fire episode, Atmos. Environ., 39, 3719–3724, 2005.
Behera, S. N. and Sharma, M.: Investigating the potential role of ammonia in
ion chemistry of fine particulate matter formation for an urban environment,
Sci. Total Environ., 408, 3569–3575, 2010.
Behera, S. N., Sharma, M., Aneja, V. P., and Balasubramanian, R.: Ammonia in
the atmosphere: a review on emission sources, atmospheric chemistry and
deposition on terrestrial bodies,
Environ. Sci. Pollut. R., 20, 8092–8131, 2013.
Berner, A. H. and Felix, J. D.: Investigating ammonia emissions in a
coastal urban airshed using stable isotope techniques, Sci. Total
Environ., 707, 134952, https://doi.org/10.1016/j.scitotenv.2019.134952,
2020.
Bhattarai, N., Wang, S., Xu, Q., Dong, Z., Chang, X., Jiang, Y., and Zheng,
H.: Sources of gaseous NH3 in urban Beijing from parallel sampling of NH3
and
Böhlke, J. K. and Coplen, T. B.: Reference and intercomparison materials
for stable isotopes of light elements, in: Proceedings of the
IAEA-TECDOC-825 Consultants Meeting Held in Vienna, Vienna, Austria, 1–3 December 1993.
Bohlke, J. K., Gwinn, C. J., and Coplen, T. B.: New Reference Materials for
Nitrogen-Isotope-Ratio Measurements, Geostandard. Newslett., 17, 159–164,
https://doi.org/10.1111/j.1751-908X.1993.tb00131.x, 1993.
Böhlke, J. K., Smith, R. L., and Hannon, J. E.: Isotopic analysis of N
and O in nitrite and nitrate by sequential selective bacterial reduction to
N2O, Anal. Chem., 79, 5888–5895, 2007.
Bouwman, A. F., Lee, D. S., Asman, W. A. H., Dentener, F. J., Van Der Hoek,
K. W., and Olivier, J. G. J.: A global high-resolution emission inventory
for ammonia, Global Biogeochem. Cy., 11, 561–587, 1997.
Cao, H., Henze, D. K., Cady-Pereira, K., McDonald, B. C., Harkins, C., Sun,
K., Bowman, K. W., Fu, T.-M., and Nawaz, M. O.: COVID-19 Lockdowns Afford
the First Satellite-Based Confirmation That Vehicles Are an Under-recognized
Source of Urban NH3 Pollution in Los Angeles, Environ. Sci.
Technol. Lett., 9, 3–9,
https://doi.org/10.1021/acs.estlett.1c00730, 2021.
Carslaw, D. C. and Ropkins, K.: Openair–an R package for air quality data
analysis, Environ. Modell. Softw., 27, 52–61, 2012.
Carslaw, D. C., Beevers, S. D., Ropkins, K., and Bell, M. C.: Detecting and
quantifying aircraft and other on-airport contributions to ambient nitrogen
oxides in the vicinity of a large international airport, Atmos. Environ., 40, 5424–5434, 2006.
Cass, G. R., Gharib, S., Peterson, M., and Tilden, J. W.: The origin of
ammonia emissions to the atmosphere in an urban area, Open file report,
82–6, 1982.
Chang, Y., Liu, X., Deng, C., Dore, A. J., and Zhuang, G.: Source apportionment of atmospheric ammonia before, during, and after the 2014 APEC summit in Beijing using stable nitrogen isotope signatures, Atmos. Chem. Phys., 16, 11635–11647, https://doi.org/10.5194/acp-16-11635-2016, 2016.
Decina, S. M., Templer, P. H., Hutyra, L. R., Gately, C. K., and Rao, P.:
Variability, drivers, and effects of atmospheric nitrogen inputs across an
urban area: emerging patterns among human activities, the atmosphere, and
soils, Sci. Total Environ., 609, 1524–1534, 2017.
Decina, S. M., Hutyra, L. R., and Templer, P. H.: Hotspots of nitrogen
deposition in the world's urban areas: a global data synthesis, Front.
Ecol. Environ., 18, 92–100, https://doi.org/10.1002/fee.2143,
2020.
Felix, D. J., Elliott, E. M., Gish, T. J., McConnell, L. L., and Shaw, S.
L.: Characterizing the isotopic composition of atmospheric ammonia emission
sources using passive samplers and a combined oxidation-bacterial
denitrifier approach, Rapid Commun. Mass Spectrom., 27,
2239–2246, 2013.
Felix, J. D., Elliott, E. M., and Gay, D. A.: Spatial and temporal patterns
of nitrogen isotopic composition of ammonia at U.S. ammonia monitoring
network sites, Atmos. Environ., 150, 434–442,
https://doi.org/10.1016/j.atmosenv.2016.11.039, 2017.
Fenn, M. E., Bytnerowicz, A., Schilling, S. L., Vallano, D. M., Zavaleta, E.
S., Weiss, S. B., Morozumi, C., Geiser, L. H., and Hanks, K.: On-road
emissions of ammonia: An underappreciated source of atmospheric nitrogen
deposition, Sci. Total Environ., 625, 909–919,
https://doi.org/10.1016/j.scitotenv.2017.12.313, 2018.
Fleming, Z. L., Monks, P. S., and Manning, A. J.: Untangling the influence
of air-mass history in interpreting observed atmospheric composition,
Atmos. Res., 104, 1–39, 2012.
Frank, D. A., Evans, R. D., and Tracy, B. F.: The role of ammonia
volatilization in controlling the natural 15N abundance of a grazed
grassland, Biogeochemistry, 68, 169–178,
https://doi.org/10.1023/B:BIOG.0000025736.19381.91, 2004.
Freyer, H. D.: Seasonal trends of
Galán Madruga, D., Fernandez Patier, R., Puertas, S., García, R.,
and Cristóbal López, A.: Characterization and local emission sources
for ammonia in an urban environment, B. Environ. Contam.
Tox., 100, 593–599, 2018.
Galloway, J. N., Dentener, F. J., Capone, D. G., Boyer, E. W., Howarth, R.
W., Seitzinger, S. P., Asner, G. P., Cleveland, C., Green, P., and Holland,
E.: Nitrogen cycles: past, present, and future, Biogeochemistry, 70,
153–226, 2004.
Gu, M., Pan, Y., Sun, Q., Walters, W. W., Song, L., and Fang, Y.: Is
fertilization the dominant source of ammonia in the urban atmosphere?,
Sci. Total Environ., 838, 155890,
https://doi.org/10.1016/j.scitotenv.2022.155890, 2022a.
Gu, M., Pan, Y., Walters, W. W., Sun, Q., Song, L., Wang, Y., Xue, Y., and
Fang, Y.: Vehicular Emissions Enhanced Ammonia Concentrations in Winter
Mornings: Insights from Diurnal Nitrogen Isotopic Signatures, Environ. Sci.
Technol., 56, 1578–1585, https://doi.org/10.1021/acs.est.1c05884, 2022b.
Heaton, T. H. E.: 15N14N ratios of nitrate and ammonium in rain at Pretoria,
South Africa, Atmos. Environ., 21, 843–852, 1987.
Hristov, A. N., Zaman, S., Vander Pol, M., Ndegwa, P., Campbell, L., and
Silva, S.: Nitrogen losses from dairy manure estimated through nitrogen mass
balance and chemical markers, J. Environ. Qual., 38,
2438–2448, 2009.
Hu, Q., Zhang, L., Evans, G. J., and Yao, X.: Variability of atmospheric
ammonia related to potential emission sources in downtown Toronto, Canada,
Atmos. Environ., 99, 365–373,
https://doi.org/10.1016/j.atmosenv.2014.10.006, 2014.
Jickells, T. D., Kelly, S. D., Baker, A. R., Biswas, K., Dennis, P. F.,
Spokes, L. J., Witt, M., and Yeatman, S. G.: Isotopic evidence for a marine
ammonia source, Geophys. Res. Lett., 30, 1374,
https://doi.org/10.1029/2002GL016728, 2003.
Joyce, E. E., Walters, W. W., Roy, E. L., Clark, S. C., Schiebel, H., and
Hastings, M. G.: Highly concentrated atmospheric inorganic nitrogen
deposition in an urban, coastal region in the US, Environ. Res. Commun., 2,
081001, https://doi.org/10.1088/2515-7620/aba637, 2020.
Kawashima, H. and Ono, S.: Nitrogen Isotope Fractionation from Ammonia Gas
to Ammonium in Particulate Ammonium Chloride, Environ. Sci. Technol., 53,
10629–10635, https://doi.org/10.1021/acs.est.9b01569, 2019.
Kawashima, H., Ogata, R., and Gunji, T.: Laboratory-based validation of a
passive sampler for determination of the nitrogen stable isotope ratio of
ammonia gas, Atmos. Environ., 245, 118009,
https://doi.org/10.1016/j.atmosenv.2020.118009, 2021.
Kim, Y. P., Seinfeld, J. H., and Saxena, P.: Atmospheric gas-aerosol
equilibrium I. Thermodynamic model, Aerosol Sci. Technol., 19,
157–181, 1993.
Koutrakis, P., Wolfson, J. M., and Spengler, J. D.: An improved method for
measuring aerosol strong acidity: results from a nine-month study in St
Louis, Missouri and Kingston, Tennessee, Atmos. Environ., 22,
157–162, 1988.
Koutrakis, P., Sioutas, C., Ferguson, S. T., Wolfson, J. M., Mulik, J. D.,
and Burton, R. M.: Development and evaluation of a glass honeycomb
denuder/filter pack system to collect atmospheric gases and particles,
Environ. Sci. Technol., 27, 2497–2501, 1993.
Li, M., Weschler, C. J., Beko, G., Wargocki, P., Lucic, G., and Williams,
J.: Human ammonia emission rates under various indoor environmental
conditions, Environ. Sci. Technol., 54, 5419–5428, 2020.
Liu, J., Ding, P., Zong, Z., Li, J., Tian, C., Chen, W., Chang, M., Salazar,
G., Shen, C., and Cheng, Z.: Evidence of rural and suburban sources of urban
haze formation in China: a case study from the Pearl River Delta region,
J. Geophys. Res.-Atmos., 123, 4712–4726, 2018.
McIlvin, M. R. and Altabet, M. A.: Chemical Conversion of Nitrate and
Nitrite to Nitrous Oxide for Nitrogen and Oxygen Isotopic Analysis in
Freshwater and Seawater, Anal. Chem., 77, 5589–5595,
https://doi.org/10.1021/ac050528s, 2005.
Meng, Z. Y., Lin, W. L., Jiang, X. M., Yan, P., Wang, Y., Zhang, Y. M., Jia, X. F., and Yu, X. L.: Characteristics of atmospheric ammonia over Beijing, China, Atmos. Chem. Phys., 11, 6139–6151, https://doi.org/10.5194/acp-11-6139-2011, 2011.
Muzio, L. J. and Arand, J. K.: Homogeneous Gas Phase Decomposition of Oxides
of Nitrogen. Tustin, CA, KVB Incorporated, Electric Power Research Institute
report FP-253, Project, 461, 1976.
Nowak, J. B., Huey, L. G., Russell, A. G., Tian, D., Neuman, J. A., Orsini,
D., Sjostedt, S. J., Sullivan, A. P., Tanner, D. J., Weber, R. J., Nenes, A., Edgerton, E., and Fehsenfeld, F. C.: Analysis of urban gas phase ammonia measurements from the 2002
Atlanta Aerosol Nucleation and Real-Time Characterization Experiment
(ANARChE), J. Geophys. Res.-Atmos., 111, D17308, https://doi.org/10.1029/2006JD007113,
2006.
Pan, Y., Tian, S., Liu, D., Fang, Y., Zhu, X., Zhang, Q., Zheng, B.,
Michalski, G., and Wang, Y.: Fossil Fuel Combustion-Related Emissions
Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence
from 15N-Stable Isotope in Size-Resolved Aerosol Ammonium, Environ. Sci.
Technol., 50, 8049–8056, https://doi.org/10.1021/acs.est.6b00634, 2016.
Pan, Y., Tian, S., Liu, D., Fang, Y., Zhu, X., Gao, M., Gao, J., Michalski,
G., and Wang, Y.: Isotopic evidence for enhanced fossil fuel sources of
aerosol ammonium in the urban atmosphere, Environ. Pollut., 238,
942–947, 2018.
Pan, Y., Gu, M., Song, L., Tian, S., Wu, D., Walters, W. W., Yu, X., Lü,
X., Ni, X., and Wang, Y.: Systematic low bias of passive samplers in
characterizing nitrogen isotopic composition of atmospheric ammonia,
Atmos. Res., 243, 105018,
https://doi.org/10.1016/j.atmosres.2020.105018, 2020.
Pandolfi, M., Amato, F., Reche, C., Alastuey, A., Otjes, R. P., Blom, M. J., and Querol, X.: Summer ammonia measurements in a densely populated Mediterranean city, Atmos. Chem. Phys., 12, 7557–7575, https://doi.org/10.5194/acp-12-7557-2012, 2012.
Park, R. J., Jacob, D. J., Field, B. D., Yantosca, R. M., and Chin, M.:
Natural and transboundary pollution influences on sulfate-nitrate-ammonium
aerosols in the United States: Implications for policy,
J. Geophys. Res.-Atmos., 109, D15204,
https://doi.org/10.1029/2003JD004473, 2004.
Parnell, A. C., Inger, R., Bearhop, S., and Jackson, A. L.: Source
partitioning using stable isotopes: coping with too much variation, PloS
one, 5, e9672, https://doi.org/10.1371/journal.pone.0009672, 2010.
Paulot, F., Jacob, D. J., Pinder, R. W., Bash, J. O., Travis, K., and Henze,
D. K.: Ammonia emissions in the United States, European Union, and China
derived by high-resolution inversion of ammonium wet deposition data:
Interpretation with a new agricultural emissions inventory
(MASAGE_NH3), J. Geophys. Res.-Atmos.,
119, 4343–4364, https://doi.org/10.1002/2013JD021130, 2014.
Paulot, F., Jacob, D. J., Johnson, M. T., Bell, T. G., Baker, A. R., Keene,
W. C., Lima, I. D., Doney, S. C., and Stock, C. A.: Global oceanic emission
of ammonia: Constraints from seawater and atmospheric observations, Global
Biogeochem. Cy., 29, 1165–1178, https://doi.org/10.1002/2015GB005106,
2015.
Paulot, F., Ginoux, P., Cooke, W. F., Donner, L. J., Fan, S., Lin, M.-Y., Mao, J., Naik, V., and Horowitz, L. W.: Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth, Atmos. Chem. Phys., 16, 1459–1477, https://doi.org/10.5194/acp-16-1459-2016, 2016.
Pekney, N. J., Davidson, C. I., Zhou, L., and Hopke, P. K.: Application of
PSCF and CPF to PMF-modeled sources of PM2.5 in Pittsburgh, Aerosol Sci. Technol., 40, 952–961, 2006.
Perrino, C., De Santis, F., and Febo, A.: Uptake of nitrous acid and
nitrogen oxides by nylon surfaces: Implications for nitric acid measurement,
Atmos. Environ., 22, 1925–1930,
https://doi.org/10.1016/0004-6981(88)90081-9, 1988.
Plautz, J.: Piercing the haze, Science, 361, 1060–1063,
https://doi.org/10.1126/science.361.6407.1060, 2018.
Puchalski, M. A., Rogers, C. M., Baumgardner, R., Mishoe, K. P., Price, G.,
Smith, M. J., Watkins, N., and Lehmann, C. M.: A statistical comparison of
active and passive ammonia measurements collected at Clean Air Status and
Trends Network (CASTNET) sites, Environ. Sci.-Proc.
Imp., 17, 358–369, 2015.
Reche, C., Viana, M., Pandolfi, M., Alastuey, A., Moreno, T., Amato, F.,
Ripoll, A., and Querol, X.: Urban NH3 levels and sources in a Mediterranean
environment, Atmos. Environ., 57, 153–164,
https://doi.org/10.1016/j.atmosenv.2012.04.021, 2012.
Savard, M. M., Cole, A., Smirnoff, A., and Vet, R.: δ15N values of
atmospheric N species simultaneously collected using sector-based samplers
distant from sources – Isotopic inheritance and fractionation, Atmos. Environ., 162, 11–22, https://doi.org/10.1016/j.atmosenv.2017.05.010,
2017.
Shah, V., Jaeglé, L., Thornton, J. A., Lopez-Hilfiker, F. D., Lee, B.
H., Schroder, J. C., Campuzano-Jost, P., Jimenez, J. L., Guo, H., Sullivan,
A. P., Weber, R. J., Green, J. R., Fiddler, M. N., Bililign, S., Campos, T.
L., Stell, M., Weinheimer, A. J., Montzka, D. D., and Brown, S. S.: Chemical
feedbacks weaken the wintertime response of particulate sulfate and nitrate
to emissions reductions over the eastern United States, P. Natl. Acad. Sci. USA, 115,
8110–8115, https://doi.org/10.1073/pnas.1803295115, 2018.
Song, L., Walters, W. W., Pan, Y., Li, Z., Gu, M., Duan, Y., Lü, X., and
Fang, Y.: 15N natural abundance of vehicular exhaust ammonia, quantified by
active sampling techniques, Atmos. Environ., 255, 118430,
https://doi.org/10.1016/j.atmosenv.2021.118430, 2021.
Stein, A. F., Draxler, R. R., Rolph, G. D., Stunder, B. J., Cohen, M. D.,
and Ngan, F.: NOAA's HYSPLIT atmospheric transport and dispersion modeling
system, B. Am. Meteorol. Soc., 96, 2059–2077,
2015.
Suarez-Bertoa, R., Zardini, A. A., and Astorga, C.: Ammonia exhaust
emissions from spark ignition vehicles over the New European Driving Cycle,
Atmos. Environ., 97, 43–53,
https://doi.org/10.1016/j.atmosenv.2014.07.050, 2014.
Suarez-Bertoa, R., Mendoza-Villafuerte, P., Riccobono, F., Vojtisek, M.,
Pechout, M., Perujo, A., and Astorga, C.: On-road measurement of NH3
emissions from gasoline and diesel passenger cars during real world driving
conditions, Atmos. Environ., 166, 488–497,
https://doi.org/10.1016/j.atmosenv.2017.07.056, 2017.
Sun, K., Tao, L., Miller, D. J., Khan, M. A., and Zondlo, M. A.: On-Road
Ammonia Emissions Characterized by Mobile, Open-Path Measurements, Environ.
Sci. Technol., 48, 3943–3950, https://doi.org/10.1021/es4047704, 2014.
Sun, K., Tao, L., Miller, D. J., Pan, D., Golston, L. M., Zondlo, M. A.,
Griffin, R. J., Wallace, H. W., Leong, Y. J., Yang, M. M., Zhang, Y.,
Mauzerall, D. L., and Zhu, T.: Vehicle Emissions as an Important Urban
Ammonia Source in the United States and China, Environ. Sci. Technol., 51,
2472–2481, https://doi.org/10.1021/acs.est.6b02805, 2017.
Sutton, M. A., Dragosits, U., Tang, Y. S., and Fowler, D.: Ammonia emissions
from non-agricultural sources in the UK, Atmos. Environ., 34,
855–869, 2000.
Tomlin, A. S., Smalley, R. J., Tate, J. E., Barlow, J. F., Belcher, S. E.,
Arnold, S. J., Dobre, A., and Robins, A.: A field study of factors
influencing the concentrations of a traffic-related pollutant in the
vicinity of a complex urban junction, Atmos. Environ., 43,
5027–5037, 2009.
Updyke, K. M., Nguyen, T. B., and Nizkorodov, S. A.: Formation of brown
carbon via reactions of ammonia with secondary organic aerosols from
biogenic and anthropogenic precursors, Atmos. Environ., 63, 22–31,
2012.
Urey, H. C.: The thermodynamic properties of isotopic substances, J. Chem.
Soc., 7, 562–581, 1947.
Uria-Tellaetxe, I. and Carslaw, D. C.: Conditional bivariate probability
function for source identification, Environ. Modell.
Softw.,
59, 1–9, 2014.
Van Damme, M., Clarisse, L., Whitburn, S., Hadji-Lazaro, J., Hurtmans, D.,
Clerbaux, C., and Coheur, P.-F.: Industrial and agricultural ammonia point
sources exposed, Nature, 564, 99–103, 2018.
Walker, J. T., Whitall, D. R., Robarge, W., and Paerl, H. W.: Ambient
ammonia and ammonium aerosol across a region of variable ammonia emission
density, Atmos. Environ., 38, 1235–1246,
https://doi.org/10.1016/j.atmosenv.2003.11.027, 2004.
Walters, W.: Data for “Quantifying the Importance of Vehicle Ammonia Emissions in an Urban Area of the Northeastern US Utilizing Nitrogen Isotopes”, Harvard Dataverse, V1, https://doi.org/10.7910/DVN/JHMBRI, 2022.
Walters, W. W. and Hastings, M. G.: Collection of Ammonia for High
Time-Resolved Nitrogen Isotopic Characterization Utilizing an Acid-Coated
Honeycomb Denuder, Anal. Chem., 90, 8051–8057,
https://doi.org/10.1021/acs.analchem.8b01007, 2018.
Walters, W. W., Chai, J., and Hastings, M. G.: Theoretical Phase Resolved
Ammonia–Ammonium Nitrogen Equilibrium Isotope Exchange Fractionations:
Applications for Tracking Atmospheric Ammonia Gas-to-Particle Conversion,
ACS Earth Space Chem., 79–89, https://doi.org/10.1021/acsearthspacechem.8b00140,
2018.
Walters, W. W., Blum, D. E., and Hastings, M. G.: Selective Collection of
Particulate Ammonium for Nitrogen Isotopic Characterization Using a
Denuder–Filter Pack Sampling Device, Anal. Chem.,
7586–7594, https://doi.org/10.1021/acs.analchem.9b00151, 2019.
Walters, W. W., Song, L., Chai, J., Fang, Y., Colombi, N., and Hastings, M. G.: Characterizing the spatiotemporal nitrogen stable isotopic composition of ammonia in vehicle plumes, Atmos. Chem. Phys., 20, 11551–11567, https://doi.org/10.5194/acp-20-11551-2020, 2020.
Wang, S., Nan, J., Shi, C., Fu, Q., Gao, S., Wang, D., Cui, H., Saiz-Lopez,
A., and Zhou, B.: Atmospheric ammonia and its impacts on regional air
quality over the megacity of Shanghai, China, Sci. Rep., 5, 15842, https://doi.org/10.1038/srep15842,
2015.
Wu, L., Ren, H., Wang, P., Chen, J., Fang, Y., Hu, W., Ren, L., Deng, J.,
Song, Y., and Li, J.: Aerosol ammonium in the urban boundary layer in
Beijing: insights from nitrogen isotope ratios and simulations in summer
2015, Environ. Sci. Tech. Lett., 6, 389–395, 2019.
Xiao, H.-W., Wu, J.-F., Luo, L., Liu, C., Xie, Y.-J., and Xiao, H.-Y.:
Enhanced biomass burning as a source of aerosol ammonium over cities in
central China in autumn, Environ. Pollut., 266, 115278, https://doi.org/10.1016/j.envpol.2020.115278, 2020.
Yao, X. and Zhang, L.: Trends in atmospheric ammonia at urban, rural, and remote sites across North America, Atmos. Chem. Phys., 16, 11465–11475, https://doi.org/10.5194/acp-16-11465-2016, 2016.
Yao, X., Hu, Q., Zhang, L., Evans, G. J., Godri, K. J., and Ng, A. C.: Is
vehicular emission a significant contributor to ammonia in the urban
atmosphere?, Atmos. Environ., 80, 499–506,
https://doi.org/10.1016/j.atmosenv.2013.08.028, 2013.
Yu, X.-Y., Lee, T., Ayres, B., Kreidenweis, S. M., Collett, J. L., and Malm,
W.: Particulate Nitrate Measurement Using Nylon Filters, J. Air
Waste Manage., 55, 1100–1110,
https://doi.org/10.1080/10473289.2005.10464721, 2005.
Yu, X.-Y., Lee, T., Ayres, B., Kreidenweis, S. M., Malm, W., and Collett, J.
L.: Loss of fine particle ammonium from denuded nylon filters, Atmos. Environ., 40, 4797–4807, https://doi.org/10.1016/j.atmosenv.2006.03.061,
2006.
Zhang, L., Altabet, M. A., Wu, T., and Hadas, O.: Sensitive measurement of
Zhang, Y., Liu, X., Fang, Y., Liu, D., Tang, A., and Collett, J. L.:
Atmospheric Ammonia in Beijing during the COVID-19 Outbreak: Concentrations,
Sources, and Implications, Environ. Sci. Technol. Lett., 8, 32–38,
https://doi.org/10.1021/acs.estlett.0c00756, 2021.
Zhou, C., Zhou, H., Holsen, T. M., Hopke, P. K., Edgerton, E. S., and
Schwab, J. J.: Ambient Ammonia Concentrations Across New York State, J. Geophys. Res.-Atmos., 124, 8287–8302,
https://doi.org/10.1029/2019JD030380, 2019.
Short summary
Atmospheric ammonia and its products are a significant source of urban haze and nitrogen deposition. We have investigated the seasonal source contributions to a mid-sized city in the northeastern US megalopolis utilizing geospatial statistical analysis and novel isotopic constraints, which indicate that vehicle emissions were significant components of the urban-reduced nitrogen budget. Reducing vehicle ammonia emissions should be considered to improve ecosystems and human health.
Atmospheric ammonia and its products are a significant source of urban haze and nitrogen...
Altmetrics
Final-revised paper
Preprint