scholarly journals Simulating δ<sup>15</sup>N of atmospheric NO<sub><i>x</i></sub> in CMAQ version 5.2.1, based on <sup>15</sup>N incorporated SMOKE version 4.6 and WRF version 4.0 for assessing the role atmospheric processes plays in controlling the isotopic composition of NO<sub><i>x</i></sub>, NO<sub><i>y</i></sub>, and atmospheric nitrate

2021 ◽  
Author(s):  
Huan Fang ◽  
Greg Michalski
Keyword(s):  
Air Quality ◽  
Isotopic Composition ◽  
Atmospheric Chemistry ◽  
Sparse Matrix ◽  
Isotope Composition ◽  
Nox Emission ◽  
Atmospheric Measurements ◽  
Atmospheric Processes ◽  
Atmospheric Nitrate ◽  
Different Sources

Abstract. Nitrogen oxides (NOx = nitric oxide (NO) + nitrogen dioxides (NO2)) are important trace gases that affect atmospheric chemistry, air quality, and climate. Despite the importance of NOx emissions, there are significant uncertainties in NOx emission inventories. After NOx from different sources being emitted into the atmosphere, its composition will change due to atmospheric processes. In this study, we used the nitrogen stable isotope composition of NOx (δ15N(NOx)) to trace the changes in δ15N values along the journey of atmospheric NOx, by incorporating 15N into the emission input dataset prepared from the previous companion research (Fang &amp; Michalski, 2020) to run CMAQ (the Community Multiscale Air Quality Modeling System). The simulated spatiotemporal patterns in NOx isotopic composition were compared with corresponding atmospheric measurements in West Lafayette, Indiana, USA. The results indicate that estimating of atmospheric δ15N(NOx) using CMAQ shows better agreement with observation than using SMOKE (Sparse Matrix Operator Kernel Emissions), due to the consideration of mixing, disperse, transport, and deposition of NOx emission from different sources.

scholarly journals Incorporating <sup>15</sup>N into the outputs of SMOKE version 4.6 as the emission input dataset for CMAQ version 5.2.1 for assessing the role emission sources plays in controlling the isotopic composition of NO<sub>x</sub>, NO<sub>y</sub>, and atmospheric nitrate

2020 ◽  
Author(s):  
Huan Fang ◽  
Greg Michalski
Keyword(s):  
Isotopic Composition ◽  
Atmospheric Chemistry ◽  
Power Plants ◽  
Sparse Matrix ◽  
Isotope Composition ◽  
Nox Emission ◽  
Emission Sources ◽  
Emission Model ◽  
Atmospheric Measurements ◽  
Road Vehicles

Abstract. Nitrogen oxides (NOx = nitric oxide (NO) + nitrogen dioxides (NO2)) are important trace gases that affect atmospheric chemistry, air quality and climate. Contemporary development of NOx emissions inventories is limited by understanding of the roles of vegetation (net NOx source or net sink), gasoline and diesel in vehicle emissions, and application of NOx emission control technologies. In this study, we used the nitrogen stable isotope composition of NOx (δ15N(NOx) to resolve the uncertainties in NOx emission sources, by incorporating 15N into the US EPA trace gas emission model SMOKE (Sparse Matrix Operator Kernel Emissions) and compared simulated spatiotemporal patterns in NOx isotopic composition with corresponding atmospheric measurements in West Lafayette, Indiana, USA. The results indicate potential underestimation of emissions from soil, livestock waste, off-road vehicles, and natural gas power plants and the potential overestimation of emissions from on-road vehicles and coal-fired power plants.

First year of real-time VOC measurements at the SIRTA facility (Paris region, France): diurnal and seasonal variabilities, impact of lockdowns on air quality

2021 ◽  
Author(s):  
Leïla Simon ◽  
Valérie Gros ◽  
Jean-Eudes Petit ◽  
François Truong ◽  
Roland Sarda-Esteve ◽  
...  
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
Seasonal Variability ◽  
Anthropogenic Sources ◽  
First Year ◽  
Good Representation ◽  
Atmospheric Measurements ◽  
Paris Region ◽  
The Impact

&lt;p&gt;Volatile Organic Compounds (VOCs) have direct influences on air quality and climate. They also play a key role in atmospheric chemistry, as they are precursors of secondary pollutants, such as ozone (O&lt;sub&gt;3&lt;/sub&gt;) and secondary organic aerosols (SOA).&lt;/p&gt;&lt;p&gt;Long-term datasets of in-situ atmospheric measurements are crucial to characterize the variability of atmospheric chemical composition. Online and continuous measurements of O&lt;sub&gt;3&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt; and aerosols have been achieved at the SIRTA-ACTRIS facility (Paris region, France), since 2012. Regarding VOCs, they have been measured there for several years thanks to bi-weekly samplings followed by offline Gas Chromatography analysis. However, this method doesn&amp;#8217;t provide a good representation of the temporal variability of VOC concentrations. To tackle this issue, online VOC measurements using a Proton-Transfer-Reaction Quadrupole Mass-Spectrometer (PTR-Q-MS) have been started in January 2020.&lt;/p&gt;&lt;p&gt;The dataset acquired during the first year of online VOC measurements is analyzed, which gives insights on VOC seasonal variability. The additional long-term datasets obtained from co-located measurements (O&lt;sub&gt;3&lt;/sub&gt;, NO&lt;sub&gt;x&lt;/sub&gt;, aerosol physical and chemical properties, meteorological parameters) are also used for the sake of this study.&lt;/p&gt;&lt;p&gt;Due to Covid-19 pandemic, the year 2020 notably comprised a total lockdown in France in Spring, and a lighter one in Autumn. Therefore, a focus can be made on the impact of these lockdowns on the VOC variability and sources. To this end, the diurnal cycles of VOCs considered markers for anthropogenic sources are carefully investigated. Results notably indicate that markers for traffic and wood burning sources behave quite differently during the Spring lockdown in comparison to the other periods. A source apportionment analysis using positive matrix factorization allows to further document the seasonal variability of VOC sources and the impacts on air quality associated with the lockdown measures.&lt;/p&gt;

Major influence of BrO on the NOx and nitrate budgets in the Arctic spring, inferred from Δ17O(NO3 - ) measurements during ozone depletion events

2007 ◽  
Vol 4 (4) ◽  
pp. 238 ◽  
Author(s):  
S. Morin ◽  
J. Savarino ◽  
S. Bekki ◽  
A. Cavender ◽  
P. B. Shepson ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Isotopic Composition ◽  
Atmospheric Chemistry ◽  
Ozone Depletion ◽  
Lower Atmosphere ◽  
The Arctic ◽  
Major Influence ◽  
Peroxy Radicals ◽  
Bromine Oxide ◽  
Atmospheric Nitrate

Environmental context. Ozone depletion events (ODEs) in the Arctic lower atmosphere drive profound changes in the chemistry of nitrogen oxides (NOx) because of the presence of bromine oxide (BrO). These are investigated using the isotopic composition of atmospheric nitrate (NO3–), which is a ubiquitous species formed through the oxidation of nitrogen oxides. Since BrO is speculated to play a key role in the atmospheric chemistry of marine regions and in the free troposphere, our studies contribute to the improvement of the scientific knowledge on this new topic in atmospheric chemistry. Abstract. The triple oxygen isotopic composition of atmospheric inorganic nitrate was measured in samples collected in the Arctic in springtime at Alert, Nunavut and Barrow, Alaska. The isotope anomaly of nitrate (Δ17O = δ17O–0.52δ18O) was used to probe the influence of ozone (O3), bromine oxide (BrO), and peroxy radicals (RO2) in the oxidation of NO to NO2, and to identify the dominant pathway that leads to the production of atmospheric nitrate. Isotopic measurements confirm that the hydrolysis of bromine nitrate (BrONO2) is a major source of nitrate in the context of ozone depletion events (ODEs), when brominated compounds primarily originating from sea salt catalytically destroy boundary layer ozone. They also show a case when BrO is the main oxidant of NO into NO2.

scholarly journals Effect of land cover on atmospheric processes and air quality over the continental United States – a NASA unified WRF (NU-WRF) model study

2013 ◽  
Vol 13 (2) ◽  
pp. 5429-5475 ◽  
Author(s):  
Z. Tao ◽  
J. A. Santanello ◽  
M. Chin ◽  
S. Zhou ◽  
Q. Tan ◽  
...  
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Air Quality ◽  
Land Cover ◽  
Atmospheric Chemistry ◽  
Land Surface ◽  
Vegetation Type ◽  
Sensible Heat Flux ◽  
Wrf Model ◽  
Atmospheric Processes

Abstract. The land surface plays a crucial role in regulating water and energy fluxes at the land–atmosphere (L–A) interface and controls many processes and feedbacks in the climate system. Land cover and vegetation type remains one key determinant of soil moisture content that impacts air temperature, planetary boundary layer (PBL) evolution, and precipitation through soil moisture–evapotranspiration coupling. In turn it will affect atmospheric chemistry and air quality. This paper presents the results of a modeling study of the effect of land cover on some key L–A processes with a focus on air quality. The newly developed NASA Unified Weather Research and Forecast (NU-WRF) modeling system couples NASA's Land Information System (LIS) with the community WRF model and allows users to explore the L–A processes and feedbacks. Three commonly used satellite-derived land cover datasets, i.e. from the US Geological Survey (USGS) and University of Maryland (UMD) that are based on the Advanced Very High Resolution Radiometer (AVHRR) and from the Moderate Resolution Imaging Spectroradiometer (MODIS), bear large differences in agriculture, forest, grassland, and urban spatial distributions in the continental United States, and thus provide an excellent case to investigate how land cover change would impact atmospheric processes and air quality. The weeklong simulations demonstrate the noticeable differences in soil moisture/temperature, latent/sensible heat flux, PBL height, wind, NO2/ozone, and PM2.5 air quality. These discrepancies can be traced to associate with the land cover properties, e.g. stomatal resistance, albedo and emissivity, and roughness characteristics. It also implies that the rapid urban growth may have complex air quality implications with reductions in peak ozone but more frequent high ozone events.

scholarly journals Effect of land cover on atmospheric processes and air quality over the continental United States – a NASA Unified WRF (NU-WRF) model study

2013 ◽  
Vol 13 (13) ◽  
pp. 6207-6226 ◽  
Author(s):  
Z. Tao ◽  
J. A. Santanello ◽  
M. Chin ◽  
S. Zhou ◽  
Q. Tan ◽  
...  
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Air Quality ◽  
Land Cover ◽  
Atmospheric Chemistry ◽  
Land Surface ◽  
Vegetation Type ◽  
Sensible Heat Flux ◽  
Wrf Model ◽  
Atmospheric Processes

Abstract. The land surface plays a crucial role in regulating water and energy fluxes at the land–atmosphere (L–A) interface and controls many processes and feedbacks in the climate system. Land cover and vegetation type remains one key determinant of soil moisture content that impacts air temperature, planetary boundary layer (PBL) evolution, and precipitation through soil-moisture–evapotranspiration coupling. In turn, it will affect atmospheric chemistry and air quality. This paper presents the results of a modeling study of the effect of land cover on some key L–A processes with a focus on air quality. The newly developed NASA Unified Weather Research and Forecast (NU-WRF) modeling system couples NASA's Land Information System (LIS) with the community WRF model and allows users to explore the L–A processes and feedbacks. Three commonly used satellite-derived land cover datasets – i.e., from the US Geological Survey (USGS) and University of Maryland (UMD), which are based on the Advanced Very High Resolution Radiometer (AVHRR), and from the Moderate Resolution Imaging Spectroradiometer (MODIS) – bear large differences in agriculture, forest, grassland, and urban spatial distributions in the continental United States, and thus provide an excellent case to investigate how land cover change would impact atmospheric processes and air quality. The weeklong simulations demonstrate the noticeable differences in soil moisture/temperature, latent/sensible heat flux, PBL height, wind, NO2/ozone, and PM2.5 air quality. These discrepancies can be traced to associate with the land cover properties, e.g., stomatal resistance, albedo and emissivity, and roughness characteristics. It also implies that the rapid urban growth may have complex air quality implications with reductions in peak ozone but more frequent high ozone events.

Developing high-resolution simulations of tropospheric NO2 over Flanders using WRF-Chem

2021 ◽  
Author(s):  
Catalina Poraicu ◽  
Jean-François Müller ◽  
Trissevgeni Stavrakou ◽  
Dominique Fonteyn ◽  
Frederik Tack ◽  
...  
Keyword(s):  
Air Quality ◽  
High Resolution ◽  
Atmospheric Chemistry ◽  
Model Performance ◽  
Wrf Model ◽  
Chemical Mechanism ◽  
Atmospheric Models ◽  
Atmospheric Measurements ◽  
Measured Concentration ◽  
Atmospheric Species

&lt;p&gt;Atmospheric chemistry is critical in determining air quality and thus impacts climate change. Anthropogenic species are released into the atmosphere, and undergo complex photochemical transformations leading to the production of secondary pollutants, among which ozone and particulate matter. This can induce adverse effects on human health, visibility, ecosystems and local meteorology. &amp;#160;The combination of state-of-the-art atmospheric models with accurate atmospheric measurements of atmospheric species abundances is needed to evaluate whether atmospheric models can successfully simulate the chemical and physical processes occurring, and hopefully monitor the emissions of anthropogenic compounds and help in the implementation and verification of abatement policies.&lt;/p&gt;&lt;p&gt;In this work, ground-based, airborne and spaceborne measuring techniques are used to evaluate the performance of the full chemistry on-line WRF-Chem model over Antwerp in Flanders, Belgium, one of the areas with the highest NO2 pollution in the world. The model is configured to allow two nested domains with spatial resolution changing from 5 to 1km, so as to pinpoint the most pollutant sources in the region, and applied to simulate the urban air quality over the Antwerp agglomeration.&lt;/p&gt;&lt;p&gt;We will briefly discuss the choices and adaptations made regarding the physical parameterizations, emission inventories and chemical mechanism. The model performance is evaluated through comparison with various observation types. The physics parameterizations in WRF model &amp;#160;are evaluated through comparison against ground-based data from two meteorological stations in the Antwerp region. The WRF-Chem NO2 distributions are evaluated against (1) hourly measured concentration values from monitoring stations in Flanders, (2) vertical columns measured by an airborne hyperspectral imager APEX, providing a 2-dimensional spatial mapping, on 27 and 29 June 2019, and (3) spaceborne NO2 columns over Belgium obtained from the high-resolution TROPOMI instrument aboard S5p. The consistency of the model biases across the three datasets will be discussed, and recommendations will be made for improving model performance in this region.&lt;/p&gt;

scholarly journals i<sub>N</sub>RACM: incorporating <sup>15</sup>N into the Regional Atmospheric Chemistry Mechanism (RACM) for assessing the role photochemistry plays in controlling the isotopic composition of NO<sub><i>x</i></sub>, NO<sub><i>y</i></sub>, and atmospheric nitrate

2021 ◽  
Vol 14 (8) ◽  
pp. 5001-5022
Author(s):  
Huan Fang ◽  
Wendell W. Walters ◽  
David Mase ◽  
Greg Michalski
Keyword(s):  
Particulate Matter ◽  
Atmospheric Chemistry ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Nox Emission ◽  
Organic Nitrates ◽  
Atmospheric Nitrate ◽  
N Isotopes ◽  
N Compounds ◽  
Fractionation Factors

Abstract. Nitrogen oxides, classified as NOx (nitric oxide (NO) + nitrogen dioxide (NO2)) and NOy (NOx+ NO3, N2O5 HNO3, + HNO4+ HONO + Peroxyacetyl nitrate (PAN) + organic nitrates + any oxidized N compound), are important trace gases in the troposphere, which play an important role in the formation of ozone, particulate matter (PM), and secondary organic aerosols (SOA). There remain many uncertainties in the origin and fate of atmospheric N compounds including the understanding of NOy cycling, NOx emission budgets, unresolved issues within the heterogeneous uptake coefficients of N2O5, and the formation of organic nitrates in urban forests, to name a few. A potential tool to resolve some of these uncertainties are using natural abundance N isotopes in NOy compounds. Here we have developed a photochemical mechanism used to simulate tropospheric photochemistry to include 15N compounds and reactions as a means to simulate δ15N values in NOy compounds. The 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 192 N reactions in iNRACM were tested to see if isotope effects were relevant with respect to significantly changing the δ15N values (±1 ‰) of NOx, HONO, and/or HNO3. The isotope fractionation factors (α) for relevant reactions were assigned based on recent experimental or calculated values. Each relevant reaction in the iNRACM mechanism was tested individually and in concert in order to assess the controlling reactions. The controlling reactions and their diurnal importance are discussed. A comparison between iNRACM predictions and observed δ15N NO3- in particulate matter from Tucson, Arizona, suggests the model, and isotope fractionation factors incorporated into it, are accurately capturing the isotope effects occurring during the photochemistry of NOy. The implication is that measurements of δ15N in NOy compounds may be a new way of tracing in situ N chemistry and a means of assessing NOx emission budgets.

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