scholarly journals Non-linear response of PM2.5 to changes in NO<sub>x</sub> and NH<sub>3</sub> emissions in the Po basin (Italy): consequences for air quality plans

2021 ◽  
Author(s):  
Philippe Thunis ◽  
Alain Clappier ◽  
Matthias Beekmann ◽  
Jean Philippe Putaud ◽  
Cornelis Cuvelier ◽  
...  
Keyword(s):  
Air Quality ◽  
Emission Reduction ◽  
Oxidative Capacity ◽  
Nox Emission ◽  
Aerosol Formation ◽  
Linear Processes ◽  
Emission Reductions ◽  
Nh3 Emission ◽  
Non Linear ◽  
Pm2.5 Concentration

Abstract. Air pollution is one of the main causes of damages to human health in Europe with an estimate of about 380 000 premature deaths per year in the EU28, as the result of exposure to fine particulate matter (PM2.5) only. In this work, we focus on one specific region in Europe, the Po basin, a region where chemical regimes are the most complex, showing important non-linear processes, especially those related to interactions between NOx and NH3. We analyse the sensitivities of PM2.5 to NOx and NH3 emissions by means of a set of EMEP simulations performed with different levels of emission reductions, from 25 % up to a total switch-off of those emissions. Both single and combined precursor reduction scenarios are applied to determine the most efficient emission reduction strategies and quantify the interactions between NOx and NH3 emission reductions. The results confirmed the peculiarity of secondary PM2.5 formation in the Po basin, characterised by contrasting chemical regimes within distances of few (hundreds of) kilometres, as well as strong non-linear responses to emission reductions during wintertime. One of the striking results is the increase of the PM2.5 concentration levels when NOx emission reductions are applied in NOx-rich areas, such as the surroundings of Bergamo. The increased oxidative capacity of the atmosphere is the cause of the increase of PM2.5 induced by a reduction in NOx emission. This process can have contributed to the absence of significant PM2.5 concentration decrease during the COVID-19 lockdowns in many European cities. It is important to account for this process when designing air quality plans, since it could well lead to transitionary increases in PM2.5 at some locations in winter as NOx emission reduction measures are gradually implemented. While PM2.5 responses to NOx and NH3 emission reduction show large variations seasonally and spatially, these responses remain close to linear, i.e. proportional to the emission reduction levels, at least up to −50 % because secondary aerosol formation chemical regimes are not modified by those relatively moderate ranges.

scholarly journals Non-linear response of PM<sub>2.5</sub> to changes in NO<sub><i>x</i></sub> and NH<sub>3</sub> emissions in the Po basin (Italy): consequences for air quality plans

2021 ◽  
Vol 21 (12) ◽  
pp. 9309-9327
Author(s):  
Philippe Thunis ◽  
Alain Clappier ◽  
Matthias Beekmann ◽  
Jean Philippe Putaud ◽  
Cornelis Cuvelier ◽  
...  
Keyword(s):  
Air Quality ◽  
Emission Reduction ◽  
Fine Particulate Matter ◽  
Oxidative Capacity ◽  
Nox Emission ◽  
Linear Processes ◽  
Emission Reductions ◽  
Nh3 Emission ◽  
Non Linear ◽  
Pm2.5 Concentration

Abstract. Air pollution is one of the main causes of damages to human health in Europe, with an estimate of about 380 000 premature deaths per year in the EU28, as the result of exposure to fine particulate matter (PM2.5) only. In this work, we focus on one specific region in Europe, the Po basin, a region where chemical regimes are the most complex, showing important non-linear processes, especially those related to interactions between NOx and NH3. We analyse the sensitivity of PM2.5 concentration to NOx and NH3 emissions by means of a set of EMEP model simulations performed with different levels of emission reductions, from 25 % up to a total switch-off of those emissions. Both single and combined precursor reduction scenarios are applied to determine the most efficient emission reduction strategies and quantify the interactions between NOx and NH3 emission reductions. The results confirmed the peculiarity of secondary PM2.5 formation in the Po basin, characterised by contrasting chemical regimes within distances of a few (hundred) kilometres, as well as non-linear responses to emission reductions during wintertime. One of the striking results is the slight increase in the PM2.5 concentration levels when NOx emission reductions are applied in NOx-rich areas, such as the surroundings of Bergamo. The increased oxidative capacity of the atmosphere is the cause of the increase in PM2.5 induced by a reduction in NOx emission. This process could have contributed to the absence of a significant PM2.5 concentration decrease during the COVID-19 lockdowns in many European cities. It is important to account for this process when designing air quality plans, since it could well lead to transitionary increases in PM2.5 at some locations in winter as NOx emission reduction measures are gradually implemented. While PM2.5 chemical regimes, determined by the relative importance of the NOx vs. NH3 responses to emission reductions, show large variations seasonally and spatially, they are not very sensitive to moderate (up to 50 %–60 %) emission reductions. Beyond 25 % emission reduction strength, responses of PM2.5 concentrations to NOx emission reductions become non-linear in certain areas of the Po basin mainly during wintertime.

scholarly journals Assessment of the Effect of the Three-Year Action Plan to Fight Air Pollution on Air Quality and Associated Health Benefits in Sichuan Basin, China

2021 ◽  
Vol 13 (19) ◽  
pp. 10968
Author(s):  
Juihui Chen ◽  
Xiaoqiong Feng ◽  
Yonghui Zhu ◽  
Ling Huang ◽  
Min He ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Pollution Control ◽  
Emission Reduction ◽  
Sichuan Basin ◽  
Action Plan ◽  
Control Measures ◽  
Air Pollution Control ◽  
Premature Deaths ◽  
Pm2.5 Concentration

To continuously improve air quality, after implementation of the “Clean Air Action Plan, 2013–2017” (CAAP), the “Three-year Action Plan to Fight Air Pollution” (TYP) was further conducted from 2018 to 2020. However, the effectiveness of the TYP remains unclear in one of the major city-clusters of China, the Sichuan Basin. In this study, the bottom-up method was used to quantify the emission reduction during TYP based on the emissions inventory in Sichuan Basin in 2017 and the air pollution control measures adopted from 2018 to 2020 in each city. The reduction of PM2.5 concentration and the avoided premature deaths due to implementation of air pollution control measures were assessed by using an integrated meteorology and air quality modeling system and a concentration-response algorithm. Emissions of SO2, NOx, PM2.5, and VOCs in the Sichuan Basin have been reduced by 42.6, 105.2, 40.2, and 136.6 Gg, respectively. The control of non-electricity industry contributed significantly to the emission reduction of all pollutants, accounting for 26–49%. In addition, the control of mobile sources contributes the most to NOx reductions, accounting for 57%. The results illustrate that the focus of air pollution control in Sichuan Basin is still industrial sources. We also found that the emission reduction of NOx, PM2.5, and VOCs in Chengdu is significantly higher than that of other cities, which were about 3.4~15.4 times, 2.2~40.1 times, and 4.3~24.4 times that of other cities, respectively. In Sichuan Basin, the average reduction rate of PM2.5 concentration due to air pollution control measures was 5% on average, with the highest contributions from industry, mobile source, and dust emission control. The decrease rate in each city ranges between 1~10%, and the decreasing ratios in Dazhou (10%), Chengdu (8%), and Zigong (7%) are relatively higher. The number of premature deaths avoided due to air pollution control measures in Sichuan Basin is estimated to be 22,934. Chengdu and Dazhou have benefitted most from the air pollution control measures, with 6043 and 2713 premature deaths avoided, respectively. Our results indicate that the implementation of TYP has achieved remarkable environmental and health benefits.

scholarly journals Evaluation of the effect of regional joint-control measures on changing photochemical transformation: a comprehensive study of the optimization scenario analysis

2019 ◽  
Vol 19 (14) ◽  
pp. 9037-9060 ◽  
Author(s):  
Li Li ◽  
Shuhui Zhu ◽  
Jingyu An ◽  
Min Zhou ◽  
Hongli Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Emission Reduction ◽  
Meteorological Conditions ◽  
Air Pollutant ◽  
Control Measures ◽  
Joint Control ◽  
Emission Reductions ◽  
The Yrd ◽  
Comprehensive Study

Abstract. Heavy haze usually occurs in winter in eastern China. To control the severe air pollution during the season, comprehensive regional joint-control strategies were implemented throughout a campaign. To evaluate the effectiveness of these strategies and to provide some insights into strengthening the regional joint-control mechanism, the influence of control measures on levels of air pollution was estimated with an integrated measurement-emission-modeling method. To determine the influence of meteorological conditions, and the control measures on the air quality, in a comprehensive study, the 2nd World Internet Conference was held during 16–18 December 2015 in Jiaxing City, Zhejiang province, in the Yangtze River Delta (YRD) region. We first analyzed the air quality changes during four meteorological regimes and then compared the air pollutant concentrations before, during, and after the regulation under static meteorological conditions. Next, we conducted modeling scenarios to quantify the effects caused due to the air pollution control measures. We found that total emissions of SO2, NOx, PM2.5, and volatile organic compounds (VOCs) in Jiaxing were reduced by 56 %, 58 %, 64 %, and 80 %, respectively, while total emission reductions of SO2, NOx, PM2.5, and VOCs over the YRD region are estimated to be 10 %, 9 %, 10 %, and 11 %, respectively. Modeling results suggest that during the campaign from 8 to 18 December, PM2.5 daily average concentrations decreased by 10 µg m−3 with an average decrease of 14.6 %. Our implemented optimization analysis compared with previous studies also reveals that local emission reductions play a key role in air quality improvement, although it shall be supplemented by regional linkage. In terms of regional joint control, implementing pollution channel control 48 h before the event is of most benefit in getting similar results. Therefore, it is recommended that a synergistic emission reduction plan between adjacent areas with local pollution emission reductions as the core part should be established and strengthened, and emission reduction plans for different types of pollution through a stronger regional linkage should be reserved.

scholarly journals Modeling the impact of COVID-19 on air quality in southern California: implications for future control policies

2021 ◽  
Vol 21 (11) ◽  
pp. 8693-8708
Author(s):  
Zhe Jiang ◽  
Hongrong Shi ◽  
Bin Zhao ◽  
Yu Gu ◽  
Yifang Zhu ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
Southern California ◽  
Air Pollutant ◽  
Activity Level ◽  
Pollutant Emissions ◽  
Chemical Compositions ◽  
Emission Reductions ◽  
The Impact ◽  
Pm2.5 Concentration

Abstract. In response to the coronavirus disease of 2019 (COVID-19), California issued statewide stay-at-home orders, bringing about abrupt and dramatic reductions in air pollutant emissions. This crisis offers us an unprecedented opportunity to evaluate the effectiveness of emission reductions in terms of air quality. Here we use the Weather Research and Forecasting model with Chemistry (WRF-Chem) in combination with surface observations to study the impact of the COVID-19 lockdown measures on air quality in southern California. Based on activity level statistics and satellite observations, we estimate the sectoral emission changes during the lockdown. Due to the reduced emissions, the population-weighted concentrations of fine particulate matter (PM2.5) decrease by 15 % in southern California. The emission reductions contribute 68 % of the PM2.5 concentration decrease before and after the lockdown, while meteorology variations contribute the remaining 32 %. Among all chemical compositions, the PM2.5 concentration decrease due to emission reductions is dominated by nitrate and primary components. For O3 concentrations, the emission reductions cause a decrease in rural areas but an increase in urban areas; the increase can be offset by a 70 % emission reduction in anthropogenic volatile organic compounds (VOCs). These findings suggest that a strengthened control on primary PM2.5 emissions and a well-balanced control on nitrogen oxides and VOC emissions are needed to effectively and sustainably alleviate PM2.5 and O3 pollution in southern California.

scholarly journals Downscaling of air pollutants in Europe using uEMEP_v6

2021 ◽  
Author(s):  
Qing Mu ◽  
Bruce Rolstad Denby ◽  
Eivind Grøtting Wærsted ◽  
Hilde Fagerli
Keyword(s):  
Air Quality ◽  
High Resolution ◽  
Spatial Correlation ◽  
Transport Model ◽  
Chemical Transport Model ◽  
Proxy Data ◽  
Linear Processes ◽  
Frequency Distributions ◽  
Non Linear ◽  
Pm2.5 And Pm10

Abstract. The air quality downscaling model uEMEP and its combination with the EMEP MSC-W chemical transport model are used here to achieve high-resolution air quality modeling at street level in Europe. By using publicly available proxy data, this uEMEP/EMEP modelling system is applied to calculate annual mean NO2, PM2.5, PM10 and O3 concentrations for all of Europe down to 100 m resolution and is validated against all available Airbase monitoring stations in Europe at 25 m resolution. Downscaling is carried out on annual mean concentrations, requiring special attention to non-linear processes, such as NO2 chemistry, where frequency distributions are applied to better represent the non-linear NO2 chemistry. The downscaling shows significant improvement in NO2 concentrations where spatial correlation has been doubled for most countries and bias reduced from −46 % to −18 % for all stations in Europe. The downscaling of PM2.5 and PM10 does not show improvement in spatial correlation but does reduce the overall bias in the European calculations from −21 % to −11 % and from −39 % to −30 % for PM2.5 and PM10 respectively. There is improved spatial correlation in most countries after downscaling of O3, and a reduced positive bias of O3 concentrations from +16 % to +11 %. Sensitivity tests in Norway show that improvements in the emission and emission proxy data used for the downscaling can significantly improve both the NO2 and PM results. The downscaling development opens the way for improved exposure estimates, improved assessment of emissions as well as detailed calculations of source contributions to exceedances in a consistent way for all of Europe at high resolution.

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.

Air quality improvements caused by COVID-19 lockdown measures in Central Europe – contributions of emission sectors and the meteorological situation

2021 ◽  
Author(s):  
Ronny Badeke ◽  
Volker Matthias ◽  
Markus Quante ◽  
Ronny Petrik ◽  
Jan Arndt ◽  
...  
Keyword(s):  
Air Quality ◽  
Central Europe ◽  
Emission Reduction ◽  
Meteorological Data ◽  
Measurement Data ◽  
Weather Conditions ◽  
Air Pollutant ◽  
Emission Data ◽  
Emission Reductions ◽  
Ship Traffic

&lt;p&gt;Corona lockdown measures caused unprecedented emission reductions in many parts of world. However, this does not linearly translate into improved air quality, since weather phenomena like precipitation, wind and solar radiation also show a significant impact on pollutant concentration patterns. The aim of this study is to disentangle effects of emission reduction and meteorology on the air quality in Central Europe during the first major lockdown from March to June 2020. For this purpose, the Community Multiscale Air Quality Modeling System (CMAQ) was used with updated emission data for the year 2020, including time profiles for sectors and countries that approximate the lockdown emission reductions. The contributions of street traffic, air traffic, ship traffic, residential heating and industry to NO&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt;&amp;#160;and PM&lt;sub&gt;2.5&lt;/sub&gt;&amp;#160;concentrations were investigated. Meteorological data was derived from the regional COSMO model in CLimate Mode (COSMO-CLM). Additional city scale measurements were used to account for exceptional weather conditions as well as emission reduction effects at hotspots like traffic stations. Therefore, selected air pollutant and meteorological measurement data in the cities of Hamburg, Li&amp;#233;ge and Marseille are compared against the statistical trend of 2015 to 2019.&lt;/p&gt;

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 Environmental Benefits of Ultra-Low Emission (ULE) Technology Applied in China

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1693
Author(s):  
Xiaomiao Jiao ◽  
Ruijing Ni ◽  
Lulu Chen ◽  
Jamiu Adetayo Adeniran ◽  
Hongjian Weng ◽  
...  
Keyword(s):  
Emission Reduction ◽  
Power Plants ◽  
Economic Cost ◽  
Average Concentration ◽  
Control Measures ◽  
Environmental Benefits ◽  
Nh3 Emission ◽  
Low Emission ◽  
Control Scheme ◽  
Pm2.5 Concentration

Seven scenarios were designed to study the national environmental benefits of ULE in coal-fired power plants (CPPs), ULE in industrial coal burning (ICB) and NH3 emission reduction by using the GEOS-Chem model. The results showed that although the CPPs have achieved the ULE transformation target, the PM2.5 concentration across the country has decreased by 4.8% (1.4 μg/m3). Due to the complex non-linear chemical competition mechanism among nitrate and sulfate, the average concentration of nitrate in the country has increased by 1.5% (0.1 μg/m3), which has reduced the environmental benefits of the power plant emission reduction. If the ULE technology is applied to the ICB to further reduce NOx and SO2, although the PM2.5 concentration can be reduced by 10.1% (2.9 μg/m3), the concentration of nitrate will increase by 2.7% (0.2 μg/m3). Based on the CPPs-ULE, NH3 emissions reduced by 30% and 50% can significantly reduce the concentration of ammonium and nitrate, so that the PM2.5 concentration is decreased by 11.5% (3.3 μg/m3) and 16.5% (4.7 μg/m3). Similarly, based on the CPPs-ICB-ULE, NH3 emissions can be reduced by 30% and 50% and the PM2.5 concentration reduced by 15.6% (4.4 μg/m3) and 20.3% (5.8 μg/m3). The CPPs and ICB use the ULE technology to reduce NOx and SO2, thereby reducing the concentration of ammonium and sulfate, causing the PM2.5 concentration to decline, and NH3 reduction is mainly achieved through reducing the concentration of ammonium and nitrate to reduce the concentration of PM2.5. In order to better reduce the concentration of PM2.5, NOx, SO2 and NH3 emission reduction control measures should be comprehensively considered in different regions of China. By comprehensively considering the economic cost and environmental benefits of ULE in ICB and NH3 emission reduction, an optimal haze control scheme can be determined.

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