scholarly journals Inverse Modeling of Nitrogen Oxides Emissions from the 2010 Russian Wildfires by Using Satellite Measurements of Nitrogen Dioxide

Atmosphere ◽  
2016 ◽  
Vol 7 (10) ◽  
pp. 132 ◽  
Author(s):  
Evgeny Berezin ◽  
Igor Konovalov ◽  
Yulia Romanova
Keyword(s):  
Nitrogen Oxides ◽  
Nitrogen Dioxide ◽  
Inverse Modeling ◽  
Satellite Measurements

scholarly journals Modeling uncertainties for tropospheric nitrogen dioxide columns affecting satellite-based inverse modeling of nitrogen oxides emissions

2012 ◽  
Vol 12 (24) ◽  
pp. 12255-12275 ◽  
Author(s):  
J.-T. Lin ◽  
Z. Liu ◽  
Q. Zhang ◽  
H. Liu ◽  
J. Mao ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Nitrogen Dioxide ◽  
Atmospheric Chemistry ◽  
Inverse Modeling ◽  
Positive Impact ◽  
Current Knowledge ◽  
Heterogeneous Reactions ◽  
Model Errors ◽  
Chemical Parameters ◽  
Modeling Uncertainties

Abstract. Errors in chemical transport models (CTMs) interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2) and emissions of nitrogen oxides (NOx) have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI) to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 18% in July and 8% in January, the most important factor being modified uptake of the hydroperoxyl radical (HO2) on aerosols. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitude if the model is used for emission inversion without corrections. The modifications however cannot eliminate the large model underestimates in cities and other extremely polluted areas (particularly in the north) as compared to satellite retrievals, likely pointing to underestimates of the a priori emission inventory in these places with important implications for understanding of atmospheric chemistry and air quality. Note that these modifications are simplified and should be interpreted with caution for error apportionment.

scholarly journals Air pollution by nitrogen oxides in Sarajevo from 2005 to 2010

2013 ◽  
Vol 3 (3) ◽  
pp. 250-254
Author(s):  
Suad Habeš ◽  
Zarema Obradović ◽  
Aida Ridžal ◽  
Asmir Aldžić
Keyword(s):  
Air Pollution ◽  
Nitrogen Oxides ◽  
Positive Result ◽  
Nitrogen Dioxide ◽  
Total Concentration ◽  
Nitrogen Monoxide ◽  
Atmospheric Conditions ◽  
Measuring Point ◽  
Limit Values ◽  
Research Show

Introduction: Air pollution occurs when the concentration of certain substances (pollutants) reaches a size which causes its toxicity, or in other words, begins to cause harm to human health, fl ora and wildlife.Methods: Measurements were performed in the period from 2005 to 2010, at the measuring point Bjelave-Sarajevo by the method of Griess-Saltzmann. It encompasses the following parameters: NO, NO2, NOx, measured concentrations of pollutants in the atmosphere reduced to normal atmospheric conditions of 293 K (Kelvin) and pressure of 101.3 kPa (kilopascal).Results: NO concentration in the period from 2005 to 2008 was above the permitted value, but the results of research in the period between 2009 and 2010, have shown that there was a decrease in NO concentration in the atmosphere. Measurements show that the concentration of this pollutant is currently declining, which is a positive result compared to the pollution of the atmosphere by nitrogen monoxide. Furthermore, the results of the research showed that the concentration of NO2 for the period of 2005 to 2010, is in the limited values, and that has a decreasing trend, which is also a positive result compared to the pollution of the atmosphere by nitrogen dioxide. Related to the total concentration of NOx in the atmosphere, the results of the research show that their representation corresponds to the limit values existing in the Rulebook on limit values for air quality.Conclusion: The results of the research for the pollution of the atmosphere by nitrogen oxides in the investigated area show that the amount of nitrogen oxides in the atmosphere is in constant decline.

Temporal variations of atmospheric ammonia (NH3) derived from over a decade of IASI satellite measurements

2021 ◽  
Author(s):  
Martin Van Damme ◽  
Lieven Clarisse ◽  
Bruno Franco ◽  
Mark A Sutton ◽  
Jan Willem Erisman ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
The Netherlands ◽  
Temporal Variation ◽  
Temporal Variations ◽  
Meteorological Conditions ◽  
Satellite Measurements ◽  
Atmospheric Sounding ◽  
National Trends ◽  
The Impact

<p>The Infrared Atmospheric Sounding Interferometer (IASI) mission consists of a suite of three infrared sounders providing today over 13 years of consistent global measurements (from end of 2007 up to now). In this work we use the recently developed version 3 of the IASI NH<sub>3</sub> dataset to derive global, regional and national trends from 2008 to 2018. Reported national trends are analysed in the light of changing anthropogenic and pyrogenic NH<sub>3</sub> emissions, meteorological conditions and the impact of sulphur and nitrogen oxides emissions. A case study is dedicated to the Netherlands. Temporal variation on shorter timescales will also be investigated.</p>

scholarly journals Model uncertainties affecting satellite-based inverse modeling of nitrogen oxides emissions and implications for surface ozone simulation

2012 ◽  
Vol 12 (6) ◽  
pp. 14269-14327 ◽  
Author(s):  
J.-T. Lin ◽  
Z. Liu ◽  
Q. Zhang ◽  
H. Liu ◽  
J. Mao ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Atmospheric Chemistry ◽  
Inverse Modeling ◽  
Positive Impact ◽  
Current Knowledge ◽  
Surface Ozone ◽  
Heterogeneous Reactions ◽  
Model Errors ◽  
Chemical Parameters ◽  
Ozone Monitoring Instrument

Abstract. Errors in chemical transport models (CTMs) interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2) and emissions of nitrogen oxides (NOx) have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI) to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 22% in July and 10% in January. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitudes if the model is used for emission inversion without corrections. The modifications however cannot account for the large model underestimates in cities and other extremely polluted areas (particularly in the north) as compared to satellite retrievals, likely pointing to underestimates of the a priori emission inventory in these places with important implications for understanding of atmospheric chemistry and air quality. Post-model modifications also have large impacts on surface ozone concentrations with the peak values in July over North China decreasing by about 15 ppb. Individually, modification for the uptake of the hydroperoxyl radical on aerosols has the largest impact for both NO2 and ozone, followed by various other parameters important for some species in some seasons. Note that these modifications are simplified and should be used with caution for error apportionment.

Formation of Nitrogen Dioxide and Formaldehyde in a Medium Duty Diesel Engine With Oxygenated Fuels

2020 ◽  
Author(s):  
Denis Notheis ◽  
Uwe Wagner ◽  
Amin Velji ◽  
Thomas Koch
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Nitrogen Dioxide ◽  
Diesel Fuel ◽  
Oxygen Radicals ◽  
Injection Timing ◽  
Boost Pressure ◽  
Fuel Ratio ◽  
Oxygenated Fuels ◽  
Operating Points

Abstract For modern Diesel aftertreatment systems the ratio of nitrogen dioxide (NO2) to nitrogen oxides emissions (NOx) is of great importance for the conversion of total NOx especially at low loads and low engine out exhaust temperatures. As known from previous studies the relative air-fuel ratio and so the increase of oxygen has a major impact on the in-cylinder formation of NO2. As the focus lies mainly on increasing the relative air-fuel ratio by increasing the boost pressure the influence of bounded oxygen in oxygenated fuels is not yet fully understood and is therefore in the focus of this papers. Bounded oxygen offers the potential to release oxygen radicals, which can increase NO2 formation from nitrogen monoxide (NO) at higher pressures according to the principle of Le Chatelier. At low pressures, however, released oxygen radicals can also lead to a reduction of NO2. Additionally, concerning the in-cylinder formation of NO2, the formation of formaldehyde (HCHO) is focused in this investigation, too. Especially for the oxygenated fuel like OME3–5 which can be interpreted as a compound of formaldehyde molecules the HCHO emission might increase. Although HCHO has not yet been regulated for vehicles, its carcinogenic properties require its reduction as far as possible. In this paper, investigations are presented which were carried out on a single-cylinder Diesel engine with different oxygenated fuels such as oxymethylene ether compounds (OME3–5) and 2-ethoxyethyl ether (2-EEE) and blends of these components with conventional Diesel fuel. The relevant exhaust gas components were measured using different analysis method for high accuracy and mutual validation. To analyze the effects of the fuel composition on nitrogen dioxide and formaldehyde formation the fuels are compared with pure Diesel fuel operation. Several operating points were investigated together while varying engine parameters such as relative air-fuel ratio, EGR rate, injection timing and injection pressure in a one-factor-time parameter study. Additionally, at a low load operating point a Design of Experiments (DoE) study was done to see the statistical impact and the main influencing parameters of the formation of NO2 and HCHO. Furthermore, other typical Diesel emissions like particulates, carbon monoxide and the total nitrogen oxides are investigated and compared. The investigations show an inconsistent behavior at different operating points for NO2. In most operating points a decrease of NO2 is visible, which was attributed to a decrease of the total NOx emission. Especially at higher relative air-fuel ratios and so high charge pressures the potential of oxygenated fuels to increase the NO2 to NOx ratio becomes apparent. Due to the very low particulates emissions which can be achieved with OME3–5 fuel, no restriction on low relative air/fuel ratios and higher EGR rates regarding the particulate emissions (smoke limit) exists. The HCHO emissions show different behavior in these restriction zones. At partial load, high EGR rates and low relative air-fuel ratios, HCHO emissions increase. In contrast, when the load is increased and the stoichiometric conditions are reached, the HCHO emissions decrease.

scholarly journals Abrupt decline in tropospheric nitrogen dioxide over China after the outbreak of COVID-19

2020 ◽  
Vol 6 (28) ◽  
pp. eabc2992 ◽  
Author(s):  
Fei Liu ◽  
Aaron Page ◽  
Sarah A. Strode ◽  
Yasuko Yoshida ◽  
Sungyeon Choi ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Fuel Consumption ◽  
Fossil Fuel ◽  
Economic Impacts ◽  
Economic Consequences ◽  
Economic Activities ◽  
Satellite Measurements ◽  
Vertical Column ◽  
Policy Interventions ◽  
Fossil Fuel Consumption

China’s policy interventions to reduce the spread of the coronavirus disease 2019 have environmental and economic impacts. Tropospheric nitrogen dioxide indicates economic activities, as nitrogen dioxide is primarily emitted from fossil fuel consumption. Satellite measurements show a 48% drop in tropospheric nitrogen dioxide vertical column densities from the 20 days averaged before the 2020 Lunar New Year to the 20 days averaged after. This decline is 21 ± 5% larger than that from 2015 to 2019. We relate this reduction to two of the government’s actions: the announcement of the first report in each province and the date of a province’s lockdown. Both actions are associated with nearly the same magnitude of reductions. Our analysis offers insights into the unintended environmental and economic consequences through reduced economic activities.

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