Weekly cycle of NOx emissions as laboratory of atmospheric chemistry

2021 ◽  
Author(s):  
Steffen Beirle ◽  
Steffen Dörner ◽  
Vinod Kumar ◽  
Thomas Wagner
Keyword(s):  
Atmospheric Chemistry ◽  
Emission Reduction ◽  
Power Plants ◽  
Nox Emissions ◽  
Satellite Measurements ◽  
Weekly Cycle ◽  
Christian Culture ◽  
Tropospheric No2 ◽  
Reduction Of Nox ◽  
The Mean

<p>Satellite observations provide unique information on the amount and spatial distribution of tropospheric NO2. Several studies use such datasets for deriving NOx emissions. However, due to nonlinearities in the NOx chemistry (i.e., the dependency of the OH concentration and thus the NO2 lifetime on the NO2 concentration), the observed column densities of NO2 are not directly proportional to the underlying NOx emissions. Consequently, a certain reduction in NOx emissions could result in disproportionate reduction of the corresponding NO2 columns, which could be stronger or weaker depending on the chemical state (O3, NOx and VOC levels) and conditions like temperature, humidity and acitinic flux. This effect complicates the quantification of NOx emissions from satellite measurements of NO2, and e.g. biases the emission reduction as derived from the reduction of NO2 column densities observed during recent lockdowns.  </p><p>Here we quantify the nonlinearity of the NOx system for different cities as well as power plants by investigating the effect of reduced NOx emissions on days of rest, i.e. Fridays/Sundays in Muslim/Christian culture, respectively. The reduction of NOx emissions is thereby quantified based on the continuity equation by calculating the divergence of the mean NO2 flux. This method has been proven to be sensitive for localized sources, where the uncertainties due to NO2 lifetime are small (Beirle et al., Sci. Adv., 2019). This reduction in emissions is then set in relation to the corresponding reduction of NO2 columns integrated around the source, which strongly depend on the NO2 lifetime.</p>

scholarly journals Growth in NOx emissions from power plants in China: bottom-up estimates and satellite observations

2012 ◽  
Vol 12 (10) ◽  
pp. 4429-4447 ◽  
Author(s):  
S. W. Wang ◽  
Q. Zhang ◽  
D. G. Streets ◽  
K. B. He ◽  
R. V. Martin ◽  
...  
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Emission Inventory ◽  
Transport Model ◽  
Nox Emission ◽  
Nox Emissions ◽  
Large Power ◽  
Power Plant Emissions ◽  
Tropospheric No2 ◽  
Plant Emissions

Abstract. Using OMI (Ozone Monitoring Instrument) tropospheric NO2 columns and a nested-grid 3-D global chemical transport model (GEOS-Chem), we investigated the growth in NOx emissions from coal-fired power plants and their contributions to the growth in NO2 columns in 2005–2007 in China. We first developed a unit-based power plant NOx emission inventory for 2005–2007 to support this investigation. The total capacities of coal-fired power generation have increased by 48.8% in 2005–2007, with 92.2% of the total capacity additions coming from generator units with size ≥300 MW. The annual NOx emissions from coal-fired power plants were estimated to be 8.11 Tg NO2 for 2005 and 9.58 Tg NO2 for 2007, respectively. The modeled summer average tropospheric NO2 columns were highly correlated (R2 = 0.79–0.82) with OMI measurements over grids dominated by power plant emissions, with only 7–14% low bias, lending support to the high accuracy of the unit-based power plant NOx emission inventory. The ratios of OMI-derived annual and summer average tropospheric NO2 columns between 2007 and 2005 indicated that most of the grids with significant NO2 increases were related to power plant construction activities. OMI had the capability to trace the changes of NOx emissions from individual large power plants in cases where there is less interference from other NOx sources. Scenario runs from GEOS-Chem model suggested that the new power plants contributed 18.5% and 10% to the annual average NO2 columns in 2007 in Inner Mongolia and North China, respectively. The massive new power plant NOx emissions significantly changed the local NO2 profiles, especially in less polluted areas. A sensitivity study found that changes of NO2 shape factors due to including new power plant emissions increased the summer average OMI tropospheric NO2 columns by 3.8–17.2% for six selected locations, indicating that the updated emission information could help to improve the satellite retrievals.

scholarly journals Tropospheric NO<sub>2</sub> columns: a comparison between model and retrieved data from GOME measurements

2002 ◽  
Vol 2 (1) ◽  
pp. 67-78 ◽  
Author(s):  
A. Lauer ◽  
M. Dameris ◽  
A. Richter ◽  
J. P. Burrows
Keyword(s):  
Atmospheric Chemistry ◽  
Regional Differences ◽  
Climate Model ◽  
Source Distribution ◽  
Satellite Measurements ◽  
New Approach ◽  
Tropospheric No2 ◽  
Global Coverage ◽  
First Time ◽  
Fully Coupled

Abstract. Tropospheric NO2 plays a variety of significant roles in atmospheric chemistry. In the troposphere it is one of the most significant precursors of photochemical ozone (O3) production and nitric acid (HNO3). In this study tropospheric NO2 columns were calculated by the fully coupled chemistry-climate model ECHAM4.L39(DLR)/CHEM. These have been compared with tropospheric NO2 columns, retrieved using the tropospheric excess method from measurements by the Global Ozone Monitoring Experiment (GOME) of up-welling earthshine radiance and the extraterrestrial irradiance. GOME is part of the core payload of the second European Research Satellite (ERS-2). For this study the first five years of GOME measurements have been used. The period of five years of observational data is sufficiently long to facilitate for the first time a comparison based on climatological averages with global coverage, focussing on the geographical distribution of the tropospheric NO2. A new approach of analysing regional differences (i.e. on continental scales) by calculating individual averages for different environments provides more detailed information about specific NOx sources and of their seasonal variations. The results obtained enable the validity of the model NO2 source distribution and the assumptions used to separate tropospheric and stratospheric parts of the NO2 column amount from the satellite measurements to be investigated.

scholarly journals NO<sub>x</sub> emissions in China: historical trends and future perspectives

2013 ◽  
Vol 13 (6) ◽  
pp. 16047-16112 ◽  
Author(s):  
B. Zhao ◽  
S. X. Wang ◽  
J. Y. Xu ◽  
K. Fu ◽  
Z. Klimont ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Emission Reduction ◽  
Power Plants ◽  
Ambient Air ◽  
Control Measures ◽  
Nox Emission ◽  
Nox Emissions ◽  
Emission Scenarios ◽  
Emission Reductions ◽  
Stringent Control

Abstract. Nitrogen oxides (NOx) are key pollutants for the improvement of ambient air quality. Within this study we estimated the historical NOx emissions in China for the period 1995–2010, and calculated future NOx emissions every five years until 2030 under six emission scenarios. Driven by the fast growth of energy consumption, we estimate the NOx emissions in China increased rapidly from 11.0 Mt in 1995 to 26.1 Mt in 2010. Power plants, industry and transportation were major sources of NOx emissions, accounting for 28.4, 34.0, and 25.4% of the total NOx emissions in 2010, respectively. Two energy scenarios, a business as usual scenario (BAU) and an alternative policy scenario (PC), were developed to project future energy consumption. In 2030, total energy consumption is projected to increase by 64 and 27% from 2010 level respectively. Three sets of end-of-pipe pollution control measures, including baseline, progressive, and stringent control case, were developed for each energy scenario, thereby constituting six emission scenarios. By 2030, the total NOx emissions are projected to increase (compared to 2010) by 36% in the baseline while policy cases result in reduction up to 61% in the most ambitious case with stringent control measures. More than a third of the reduction achieved by 2030 between least and most ambitious scenario comes from power sector and more than half is distributed equally between industry and transportation sectors. Selective Catalytic Reduction dominates the NOx emission reductions in power plants, while life style changes, control measures for industrial boilers and cement production are major contributors to reductions in industry. Timely enforcement of legislation on heavy duty vehicles would contribute significantly to NOx emission reductions. About 30% of the NOx emission reduction in 2020, and 40% of the NOx emission reduction in 2030 could be treated as the ancillary benefit of energy conservation. Sensitivity analysis was conducted to explore the impact of key factors on future emissions.

scholarly journals Weekly cycle of NO<sub>2</sub> by GOME measurements: a signature of anthropogenic sources

2003 ◽  
Vol 3 (6) ◽  
pp. 2225-2232 ◽  
Author(s):  
S. Beirle ◽  
U. Platt ◽  
M. Wenig ◽  
T. Wagner
Keyword(s):  
Atmospheric Chemistry ◽  
Fossil Fuel ◽  
Fuel Combustion ◽  
Weekend Effect ◽  
Anthropogenic Sources ◽  
Anthropogenic Source ◽  
Total Production ◽  
Fossil Fuel Combustion ◽  
Weekly Cycle ◽  
Tropospheric No2

Abstract. Nitrogen oxides (NO+NO2=NOx and reservoir species) are important trace gases in the troposphere with impact on human health, atmospheric chemistry and climate. Besides natural sources (lightning, soil emissions) and biomass burning, fossil fuel combustion is estimated to be responsible for about 50% of the total production of NOx. Since human activity in industrialized countries largely follows a seven-day cycle, fossil fuel combustion is expected to be reduced during weekends. This "weekend effect" is well known from local, ground based measurements, but has never been analysed on a global scale before. The Global Ozone Monitoring Experiment (GOME) on board the ESA-satellite ERS-2 allows measurements of NO2 column densities. By estimating and subtracting the stratospheric column, and considering radiative transfer, vertical column densities (VCD) of tropospheric NO2 can be determined (e.g. Leue et al., 2001). We demonstrate the statistical analysis of weekly cycles of tropospheric NO2 VCDs for different regions of the world. In the cycles of the industrialized regions and cities in the US, Europe and Japan a clear Sunday minimum of tropospheric NO2 VCD can be seen. Sunday NO2 VCDs are about 25-50% lower than working day levels. Metropolitan areas with other religious and cultural backgrounds (Jerusalem, Mecca) show different weekly patterns corresponding to different days of rest. In China, no weekly pattern can be found. The presence of a weekly cycle in the measured tropospheric NO2 VCD may help to identify the different anthropogenic source categories. Furthermore, we estimated the lifetime of tropospheric NO2 by analysing the mean weekly cycle exemplarily over Germany, obtaining a value of about 6 h in summer and 18-24 h in winter.

scholarly journals Tropospheric NO<sub>2</sub> columns: a comparison between model and retrieved data from GOME measurements

2001 ◽  
Vol 1 (2) ◽  
pp. 411-438
Author(s):  
A. Lauer ◽  
M. Dameris ◽  
A. Richter ◽  
J. P. Burrows
Keyword(s):  
Atmospheric Chemistry ◽  
Regional Differences ◽  
Climate Model ◽  
Source Distribution ◽  
Satellite Measurements ◽  
New Approach ◽  
Tropospheric No2 ◽  
Global Coverage ◽  
First Time ◽  
Fully Coupled

Abstract. Tropospheric NO2 plays a variety of significant roles in atmospheric chemistry. In the troposphere it is one of the most significant precursors of photochemical ozone (O3) production and nitric acid (HNO3). In this study tropospheric NO2 columns were calculated by the fully coupled chemistry-climate model ECHAM4.L39(DLR)/CHEM. These have been compared with tropospheric NO2 columns, retrieved using the tropospheric excess method from measurements by the Global Ozone Monitoring Experiment (GOME) of up-welling earthshine irradiance and the extraterrestrial radiance. GOME is part of the core payload of the second European Research Satellite (ERS-2). For this study the first five years of GOME measurements have been used. The period of five years of observational data is sufficient to enable a comparison based on climatological averages and with global coverage, focussing on the geographical distribution of the tropospheric NO2, for the first time. A new approach of analysing regional differences (i.e. on continental scales) by calculating individual averages for different environments provides more detailed information about specific NOx sources and of their seasonal variations. The results obtained enable the validity of the model NO2 source distribution and the assumptions used to separate tropospheric and stratospheric parts of the NO2 column amount from the satellite measurements to be investigated.

scholarly journals Analysis of tropospheric NO2 over Iraq using OMI satellite measurements

2020 ◽  
Vol 29 (1) ◽  
pp. 3-16
Author(s):  
Jasim Rajab ◽  
Ali Al-Salihi ◽  
Ahmed Hassan ◽  
Jasim Kadhum ◽  
Hwee San Lim
Keyword(s):  
Atmospheric Chemistry ◽  
Weather Conditions ◽  
Trace Gas ◽  
Linear Growth Rate ◽  
Anthropogenic Emissions ◽  
Ozone Monitoring Instrument ◽  
Satellite Measurements ◽  
Monsoon Period ◽  
Tropospheric No2 ◽  
Hot Weather

Tropospheric nitrogen dioxide (NO2) is a trace gas with important impact on atmospheric chemistry, human health and a key pollutant in particular cities, measured from space since the mid-1990s by the GOME, SCIAMACHY, OMI, and GOME-2 instruments. This study present ten years (monthly and yearly averaged) dataset from Ozone Monitoring Instrument (OMI) used to investigate tropospheric NO2 characteristics and variations over Iraq during 2005–2014. Annual NO2 shows an elevation from the northern to the southern and highest values was at central parts of Iraq. Monthly distributions revels higher values NO2 in winter and summer than spring and autumn seasons, and rising NO2 throughout study period over industrial and crowded urban zones. The trend analysis over Baghdad shows a linear growth rate 9.8% per year with an annual average (5.6·1015 molecules per 1 cm2). The air mass trajectory analysis as hotspot regions shows seasonal fluctuations between winter and summer seasons depend on weather conditions and topography. The increased NO2 values in winter are due to anthropogenic emissions and subsequent plumes from Europe. In addition, in summer because of hot weather and large paddy fields emissions. The lowest NO2 value was at monsoon period mostly linked to the rains. The OMI data and satellite information are able to observe the troposphere NO2 elevation at different regions.

scholarly journals Modeling NOx Emissions with an Intelligent Combinatorial Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
XiaoJuan Chen ◽  
Haiyang Zhang ◽  
Xiaoxue Xing ◽  
Hongwu Qin
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Nox Emission ◽  
Nox Emissions ◽  
Combinatorial Algorithm ◽  
Modeling Process ◽  
Modeling And Prediction ◽  
Local Areas ◽  
The Mean ◽  
Input Variables

Coal combustion is considered to be the key source of nitrogen oxide (NOx) emissions in thermal power plants. Methods for effective reduction in these emissions are critically sought on the national and global levels. Such methods typically achieve this goal through accurate modeling and prediction. However, such modeling process is difficult because of the complexity of the NOx emission mechanisms and the influence of many factors. Furthermore, real-operation data of power plants tend to be centralized in some local areas because of working condition experiment so that no single model can deal with the complicated and changeable boiler production processes. In this paper, we address this problem and propose a model intelligent combinatorial algorithm (MICA). First, the actual production data are preprocessed by a wavelet denoising algorithm, and the model input variables are selected based on a random forest algorithm. Then, several models for NOx emission prediction are constructed by various data-driven algorithms. Finally, a C4.5 algorithm is applied to intelligently combine these models. The experimental results indicate that the proposed algorithm can construct an accurate prediction model for NOx emissions based on actual operating data. The mean absolute percentage errors are within 1%. Moreover, a correlation of 0.98 between predicted and measured values was obtained by applying the MICA model.

scholarly journals Time-resolved emission reductions for atmospheric chemistry modelling in Europe during the COVID-19 lockdowns

2020 ◽  
Author(s):  
Marc Guevara ◽  
Oriol Jorba ◽  
Albert Soret ◽  
Hervé Petetin ◽  
Dene Bowdalo ◽  
...  
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
Emission Reduction ◽  
Power Plants ◽  
Road Traffic ◽  
Urban Background ◽  
Emission Reductions ◽  
Time Resolved ◽  
Wide Range ◽  
Reduction Factors

Abstract. We quantify the reductions in primary emissions due to the COVID-19 lockdowns in Europe. Our estimates are provided in the form of a dataset of reduction factors varying per country and day that will allow modelling and identifying the associated impacts upon air quality. The country- and daily-resolved reduction factors are provided for each of the following source categories: energy industry (power plants), manufacturing industry, road traffic and aviation (landing and take-off cycle). We computed the reduction factors based on open access and near-real time measured activity data from a wide range of information sources. We also trained a machine learning model with meteorological data to derive weather-normalised electricity consumption reductions. The time period covered is from 21 February, when the first European localised lockdown was implemented in the region of Lombardy (Italy), until 26 April 2020. This period includes five weeks (23 March until 26 April) with the most severe and relatively unchanged restrictions upon mobility and socio-economic activities across Europe. The computed reduction factors were combined with the Copernicus Atmosphere Monitoring Service's European emission inventory using adjusted emission temporal profiles in order to derive time-resolved emission reductions per country and pollutant sector. During the most severe lockdown period, we estimate the average emission reductions to be −33 % for NOx, −8 % for NMVOC, −7 % for SOx and −7 % for PM2.5 at the EU-30 level (EU-28 plus Norway and Switzerland). For all pollutants more than 85 % of the total reduction is attributable to road transport, except SOx. The reductions reached −50 % (NOx), −14 % (NMVOC), −12 % (SOx) and −15 % (PM2.5) in countries where the lockdown restrictions were more severe such as Italy, France or Spain. To show the potential for air quality modelling we simulated and evaluated NO2 concentration decreases in rural and urban background regions across Europe (Italy, Spain, France, Germany, United-Kingdom and Sweden). We found the lockdown measures to be responsible for NO2 reductions of up to −58 % at urban background locations (Madrid, Spain) and −44 % at rural background areas (France), with an average contribution of the traffic sector to total reductions of 86 % and 93 %, respectively. A clear improvement of the modelled results was found when considering the emission reduction factors, especially in Madrid, Paris and London where the bias is reduced with more than 90 %. Future updates will include the extension of the COVID-19 lockdown period covered, the addition of other pollutant sectors potentially affected by the restrictions (commercial/residential combustion and shipping) and the evaluation of other air quality pollutants such as O3 and PM2.5. All the emission reduction factors are provided in the supplementary material.

scholarly journals NOx emissions in China: historical trends and future perspectives

2013 ◽  
Vol 13 (19) ◽  
pp. 9869-9897 ◽  
Author(s):  
B. Zhao ◽  
S. X. Wang ◽  
H. Liu ◽  
J. Y. Xu ◽  
K. Fu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Emission Reduction ◽  
Power Plants ◽  
Ambient Air ◽  
Control Measures ◽  
Nox Emission ◽  
Nox Emissions ◽  
Emission Scenarios ◽  
Emission Reductions ◽  
Stringent Control

Abstract. Nitrogen oxides (NOx) are key pollutants for the improvement of ambient air quality. Within this study we estimated the historical NOx emissions in China for the period 1995–2010, and calculated future NOx emissions every five years until 2030 under six emission scenarios. Driven by the fast growth of energy consumption, we estimate the NOx emissions in China increased rapidly from 11.0 Mt in 1995 to 26.1 Mt in 2010. Power plants, industry and transportation were major sources of NOx emissions, accounting for 28.4%, 34.0%, and 25.4% of the total NOx emissions in 2010, respectively. Two energy scenarios, a business as usual scenario (BAU) and an alternative policy scenario (PC), were developed to project future energy consumption. In 2030, total energy consumption is projected to increase by 64% and 27% from 2010 level respectively. Three sets of end-of-pipe pollution control measures, including baseline, progressive, and stringent control case, were developed for each energy scenario, thereby constituting six emission scenarios. By 2030, the total NOx emissions are projected to increase (compared to 2010) by 36% in the baseline while policy cases result in reduction up to 61% in the most ambitious case with stringent control measures. More than a third of the reduction achieved by 2030 between least and most ambitious scenario comes from power sector, and more than half is distributed equally between industry and transportation sectors. Selective catalytic reduction dominates the NOx emission reductions in power plants, while life style changes, control measures for industrial boilers and cement production are major contributors to reductions in industry. Timely enforcement of legislation on heavy-duty vehicles would contribute significantly to NOx emission reductions. About 30% of the NOx emission reduction in 2020 and 40% of the NOx emission reduction in 2030 could be treated as the ancillary benefit of energy conservation. Sensitivity analysis was conducted to explore the impact of key factors on future emissions.

Burning Methanol and its Blends Attractive Alternative for Emission Reduction

2016 ◽  
Author(s):  
B. Chudnovsky ◽  
D. Livshits ◽  
S. Baitel
Keyword(s):  
Emission Reduction ◽  
Liquid Fuel ◽  
Turbulent Energy ◽  
Diesel Oil ◽  
Fuel Oil ◽  
Nox Emissions ◽  
So2 Emissions ◽  
Heavy Fuel Oil ◽  
Reduction Of Nox ◽  
Reduction Of Emissions

Traditional methods for reducing emissions, by modification of the firing system to control the mixing of fuel and air, the reduction of flame temperatures (for NOx emission reduction), and/or the post combustion treatment of the flue gas to remove NOx, SO2 particulates are very expensive. Hence, before implementation of expensive measures for the reduction of emissions, it is necessary to evaluate all low cost alternatives, such as burning alternative fuels and mixing it with other liquid fuels. Methanol offers these advantages, being a derivative of natural gas which is partly de-linked from oil, and is a clean burning fuel. Existing experience [1, 2] has shown that with inexpensive and minimal system modifications, methanol is easily fired and is fully feasible as an alternative fuel. Relative to heavy fuel and light fuel, methanol can achieve improved efficiency and lower NOx emissions due to the lower flame temperature and nitrogen content. Since methanol contains no sulfur, there are no SO2 emissions. The clean burning characteristics of methanol are expected to lead to clean pressure parts and lower maintenance costs. In this paper we present results for the specific 10 ton/hr industrial boiler (results of the burning of methanol in large utility boilers we presented in our earlier publications) located at DOR Chemicals. In this study we experimented with methanol fractions (from 0 to 100 % by heat) at different boiler loads and found that the methanol and heavy fuel oil mixtures enabled us to meet the commonly accepted emissions limit for NOx with zero CO emissions. SO2 emissions were also reduced according to methanol heat fraction. Methanol burning leads to a more than 10 % reduction of CO2. It should be noted that in our tests we used a special patented mixing device (the “Fuel Activation Device – FAD) developed by Turbulent Energy Inc. for preparing premixed or in-line blends. The results show that more than 50% of NOx reduction is achieved when light fuel oil is replaced by methanol and more than an 80% reduction when heavy fuel oil is replaced by methanol. For all boiler operation modes 100% of combustion efficiency is achieved. Methanol and liquid fuel blends lead to significant reduction of emissions depending on the methanol heat fraction. Burning of a blend of liquid fuel with water leads to a significant reduction of NOx. In addition, the usage of the FAD in our tests had positive effects on boiler efficiency improvement both for LFO and methanol firing. In this paper we also present the study of methanol and diesel fuel burning in diesel engine. It should be noted that blends were prepared by a using special mixing device developed by Turbulent Energy Inc. The performance of the engine using blended fuel compared to the performance of the engine with diesel fuel. It was also found that with using the blend one may achieve a more than 75 % reduction of NOx emissions when diesel oil is replaced by 20% methanol. Methanol and diesel oil co-firing leads to a reduction of SO2 emissions depending on the heat fraction of methanol. We believe that the conclusions of the work presented are general and can be applied to any other industrial, utility boiler, or diesel engine as well.

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