scholarly journals Measurement and model analyses of the ozone variation during 2006 to 2015 and its response to emission change in megacity Shanghai, China

2019 ◽  
Author(s):  
Jianming Xu ◽  
Xuexi Tie ◽  
Wei Gao ◽  
Yanfen Lin ◽  
Qingyan Fu
Keyword(s):  
Control Strategy ◽  
Fine Particles ◽  
Action Plan ◽  
Nox Reduction ◽  
Nox Emission ◽  
Transition Regime ◽  
Local Dispersion ◽  
Clean Air ◽  
Reduction Of Nox ◽  
Emission Change

Abstract. The fine particles (PM2.5) in China decrease significantly in recent years as a result of the implement of Chinese Clean Air Action Plan since 2013, while the O3 pollution is getting worse, especially in megacities such as Beijing and Shanghai. Better understanding the elevated O3 pollution in Chinese megacities and its response to emission change is important for developing an effective emission control strategy in future. In this study, we analyze the significant increasing trend of O3 concentration from 2006 to 2015 in the megacity Shanghai with the variability of 1–1.3 ppbv yr-1. It is likely attributed to the notable reduction of NOx concentration with the decreasing rate of 1.86–2.15 ppbv yr-1 accompanied with the little change of VOCs during the same period excluding the weak trends of meteorological impacts on local dispersion (wind speed), regional transport (wind direction) and O3 photolysis (solar radiation). It is further illustrated by using a state of the art regional chemical/dynamical model (WRF-Chem) to explore the O3 variation response to the reduction of NOx emission in Shanghai. The control experiment conducted in September of 2009 shows very excellent performance for O3 and NOx simulations including both the spatial distribution pattern, and the day by day variation by comparing with 6 in-situ measurements from MIRAGE-shanghai field campaign. Sensitive experiments with 30 % reduction of NOx emission from 2009 to 2015 in Shanghai estimated by Shanghai Environmental Monitoring Center shows that the calculated O3 concentrations exhibit obvious enhancement by 4–7 ppbv in urban zones with the increasing variability of 0.96–1.06 ppbv yr-1, which is well consistent with the observed O3 trend as a result of the strong VOC-limited condition for O3 production. The large reduction of NOx combined with less change of VOCs during the past ten years promotes the O3 production in Shanghai to move towards NOx-limited regime. Further analysis of WRF-Chem experiments and O3 isopleths diagram suggests that the O3 production in downtown is still under VOC-limited regime after 2015 despite of the remarkable NOx reduction, while moves to the transition regime between NOx-limited and VOC-limited in sub-urban zones. Supposing the insignificant VOCs variation persists, the O3 concentration in downtown would keep increasing till 2020 with the further 20 % reduction of NOx emission after 2015 estimated by Shanghai Clean Air Action Plan. While there are less O3 change in other regions where the O3 production is not under VOC-limited regime. The O3 production in Shanghai will switch from VOC-limited to NOx-limited regime after 2020 except downtown area which is likely close to the transition regime. As a result the O3 concentration will decrease by 2–3 ppbv in sub-urban zones, and more than 4 ppbv in suburb response to 20 % reduction of NOx emission after 2020, whereas is not sensitive to both NOx and VOCs changes in downtown. This result reveals that the control strategy of O3 pollution is a very complex process, and needs to be carefully studied.

scholarly journals Measurement and model analyses of the ozone variation during 2006 to 2015 and its response to emission change in megacity Shanghai, China

2019 ◽  
Vol 19 (14) ◽  
pp. 9017-9035 ◽  
Author(s):  
Jianming Xu ◽  
Xuexi Tie ◽  
Wei Gao ◽  
Yanfen Lin ◽  
Qingyan Fu
Keyword(s):  
Control Strategy ◽  
Fine Particles ◽  
Action Plan ◽  
Nox Reduction ◽  
Nox Emission ◽  
Daily Maximum ◽  
Nox Emissions ◽  
Transition Regime ◽  
Clean Air ◽  
Emission Change

Abstract. The fine particles (PM2.5) in China have decreased significantly in recent years as a result of the implementation of Chinese Clean Air Action Plan since 2013, while the O3 pollution is getting worse, especially in megacities such as Beijing and Shanghai. Better understanding of the elevated O3 pollution in Chinese megacities and its response to emission change is important for developing an effective emission control strategy in the future. In this study, we analyze the significant increasing trend of daily maximum O3 concentration from 2006 to 2015 in the megacity Shanghai with the variability of 0.8–1.3 ppbv yr−1. It could likely be attributed to the notable reduction in NOx concentrations with the decreasing rate of 1.86–2.15 ppbv yr−1 accompanied by the small change in VOCs during the same period by excluding the weak trends of meteorological impacts on local dispersion (wind speed), regional transport (wind direction), and O3 photolysis (solar radiation). It is further illustrated by using a state-of-the-art regional chemical and dynamical model (WRF-Chem) to explore the O3 variation response to the reduction in NOx emissions in Shanghai. The control experiment conducted for September of 2009 shows excellent performance for O3 and NOx simulations, including both the spatial distribution pattern and the day-by-day variation through comparison with six in situ measurements from the MIRAGE-Shanghai field campaign. Sensitivity experiments with 30 % reduction in NOx emissions from 2009 to 2015 in Shanghai estimated by Shanghai Environmental Monitoring Center shows that the calculated O3 concentrations exhibit obvious enhancement by 4–7 ppbv in urban zones with increasing variability of 0.96–1.06 ppbv yr−1, which is consistent with the observed O3 trend as a result of the strong VOC-limited condition for O3 production. The large reduction in NOx combined with less change in VOCs in the past 10 years promotes the O3 production in Shanghai to move towards an NOx-limited regime. Further analysis of the WRF-Chem experiments and O3 isopleth diagram suggests that the O3 production downtown is still under a VOC-limited regime after 2015 despite the remarkable NOx reduction, while it moves to the transition regime between NOx-limited and VOC-limited in sub-urban zones. Supposing the insignificant VOC variation persists, the O3 concentration downtown would keep increasing until 2020 with the further 20 % reduction in NOx emission after 2015 estimated by Shanghai Clean Air Action Plan. The O3 production in Shanghai will switch from a VOC-limited to an NOx-limited regime after 2020 except for downtown area, which is likely close to the transition regime. As a result the O3 concentration will decrease by 2–3 ppbv in sub-urban zones and by more than 4 ppbv in rural areas as a response to a 20 % reduction in NOx emission after 2020, whereas it is not sensitive to both NOx and VOC changes downtown. This result reveals that the control strategy of O3 pollution is a very complex process and needs to be carefully studied.

scholarly journals Worsening urban ozone pollution in China from 2013 to 2017 – Part 2: The effects of emission changes and implications for multi-pollutant control

2020 ◽  
Author(s):  
Yiming Liu ◽  
Tao Wang
Keyword(s):  
Urban Areas ◽  
Nox Reduction ◽  
Nox Emission ◽  
Pollutant Emissions ◽  
Anthropogenic Emission ◽  
Photolysis Rates ◽  
Ambient Concentrations ◽  
Reduction Of Nox ◽  
Reactive Gases ◽  
Aerosol Effects

Abstract. The Chinese government launched the Air Pollution Prevention and Control Action Plan in 2013, and various stringent measures have since been implemented, which have resulted in significant decreases in emissions and ambient concentrations of primary pollutants such as SO2, NOx, and particulate matter (PM). However, surface ozone (O3) concentrations have still been increasing in urban areas across the country. In a previous analysis, we examined in detail the roles of meteorological variation during 2013–2017 in the summertime surface O3 trend in various regions of China. In this study, we evaluated the effect of changes in multi-pollutant emissions from anthropogenic activities on O3 concentrations during the same period, by using an up-to-date regional chemical transport model (WRF-CMAQ) driven by an interannual anthropogenic emission inventory. The CMAQ model was improved with regard to heterogeneous reactions of reactive gases on aerosol surfaces, which led to better model performance in reproducing the ambient concentrations of those gases. The model simulations showed that the maximum daily 8-hour average (MDA8) O3 concentration in urban areas increased by 0.46 ppbv per year (ppbv a-1) (p = 0.001) from 2013 to 2017. In contrast, a slight decrease in MDA8 O3 concentrations by 0.17 ppbv a-1 (p = 0.005) in rural areas was predicted, mainly attributable to the NOx emission reduction. The effects of changes in individual pollutant emissions on O3 were also simulated. The reduction of NOx emission increased the O3 concentration in urban areas due to the non-linear NOx-volatile organic compound (VOC) chemistry and decreasing aerosol effects; the slight increase in VOCs emissions enhanced the O3 concentrations; the reduction of PM emissions increased the O3 concentrations by enhancing the photolysis rates and reducing the loss of reactive gases on aerosol surfaces; and the reduction of SO2 emissions resulted in a drastic decrease in sulfate concentrations, which increased the O3 concentrations through aerosol effects. In contrast to the unfavorable effect of the above changes in pollutant emissions on efforts to reduce surface concentrations of O3, the reduction of CO emissions did help to decrease the O3 concentrations in recent years. The dominant cause of increasing O3 concentrations due to changes in anthropogenic emission varied geographically. In Beijing, NOx and PM emission reductions were the two largest causes of the O3 increase; in Shanghai, the reduction of NOx and increase in VOC emissions were the two major causes; in Guangzhou, NOx reduction was the primary cause; and in Chengdu, the PM and SO2 emission decreases contributed most to the O3 concentration increase. Regarding the effects of decreasing concentrations of aerosols, the drop in heterogeneous uptake of reactive gases – mainly HO2 and O3 – was found to be more important than the increase in photolysis rates. The adverse effect of the reductions of NOx, SO2, and PM emissions on O3 abatement in Beijing, Shanghai, Guangzhou, and Chengdu would have been avoided if the anthropogenic VOCs emission had been reduced by 24 %, 23 %, 20 %, and 16 %, respectively, from 2013 to 2017. Our analysis revealed that the NOx reduction in recent years has helped to contain the total O3 production in China. However, to reduce O3 concentrations in major urban and industrial areas, VOCs emissions control should be added to the current NOx-SO2-PM policy.

Reduction of NOx in a Regenerative Industrial Furnace With the Addition of Methanol in the Fuel

2004 ◽  
Vol 126 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Q. Jiang ◽  
C. Zhang ◽  
J. Jiang
Keyword(s):  
Mixture Fraction ◽  
Nox Reduction ◽  
Combustion Process ◽  
Nox Emission ◽  
Moment Closure ◽  
Combustion Model ◽  
Industrial Furnace ◽  
Reduction Of Nox ◽  
Closure Method ◽  
Probability Density Function Pdf

The analysis of the combustion process and NOx emission in a gas-fired regenerative industrial furnace has been carried out numerically. The effect of the additive, methanol CH3OH, to the fuel on the NOx emission is studied. A moment closure method with the assumed β Probability Density Function (PDF) for the mixture fraction is used to model the turbulent non-premixed combustion process in the furnace. The combustion model is based on the assumption of instantaneous full chemical equilibrium. The P-1 model is chosen as the radiation model, and the Weighted-Sum-of-Gray-Gases Model is used to calculate the absorption coefficient. The numerical results showed that the use of CH3OH is effective in the reduction of NOx in a regenerative industrial furnace. The mechanism of NOx reduction by the use of CH3OH is also discussed.

scholarly journals Worsening urban ozone pollution in China from 2013 to 2017 – Part 2: The effects of emission changes and implications for multi-pollutant control

2020 ◽  
Vol 20 (11) ◽  
pp. 6323-6337 ◽  
Author(s):  
Yiming Liu ◽  
Tao Wang
Keyword(s):  
Urban Areas ◽  
Nox Reduction ◽  
Nox Emission ◽  
Pollutant Emissions ◽  
Photolysis Rates ◽  
Ambient Concentrations ◽  
Reduction Of Nox ◽  
Reactive Gases ◽  
Aerosol Effects ◽  
Surface O3

Abstract. The Chinese government launched the Air Pollution Prevention and Control Action Plan in 2013, and various stringent measures have since been implemented, which have resulted in significant decreases in emissions and ambient concentrations of primary pollutants such as SO2, NOx, and particulate matter (PM). However, surface ozone (O3) concentrations have still been increasing in urban areas across the country. In a previous analysis, we examined in detail the roles of meteorological variation during 2013–2017 in the summertime surface O3 trend in various regions of China. In this study, we evaluated the effect of changes in multi-pollutant emissions from anthropogenic activities on O3 levels during the same period by using an up-to-date regional chemical transport model (WRF-CMAQ) driven by an interannual anthropogenic emission inventory. The Community Multiscale Air Quality (CMAQ) model was improved with regard to heterogeneous reactions of reactive gases on aerosol surfaces, which led to better model performance in reproducing the ambient concentrations of those gases. The model simulations showed that the maximum daily 8 h average (MDA8) O3 mixing ratio in urban areas increased by 0.46 ppbv per year (ppbv a−1) (p=0.001) from 2013 to 2017. In contrast, a slight decrease in MDA8 O3 by 0.17 ppbv a−1 (p=0.005) in rural areas was predicted, mainly attributable to the NOx emission reduction. The effects of changes in individual pollutant emissions on O3 were also simulated. The reduction of NOx emission increased the O3 levels in urban areas due to the nonlinear NOx and volatile organic compound (VOC) chemistry and decreasing aerosol effects; the slight increase in VOC emissions enhanced the O3 levels; the reduction of PM emissions increased the O3 levels by enhancing the photolysis rates and reducing the loss of reactive gases on aerosol surfaces; and the reduction of SO2 emissions resulted in a drastic decrease in sulfate concentrations, which increased O3 through aerosol effects. In contrast to the unfavorable effect of the above changes in pollutant emissions on efforts to reduce surface O3, the reduction of CO emissions did help to decrease the O3 level in recent years. The dominant cause of increasing O3 due to changes in anthropogenic emissions varied geographically. In Beijing, NOx and PM emission reductions were the two largest causes of the O3 increase; in Shanghai, the reduction of NOx and increase in VOC emissions were the two major causes; in Guangzhou, NOx reduction was the primary cause; in Chengdu, the PM and SO2 emission decreases contributed most to the O3 increase. Regarding the effects of decreasing concentrations of aerosols, the drop in heterogeneous uptake of reactive gases – mainly HO2 and O3 – was found to be more important than the increase in photolysis rates. The adverse effect of the reductions of NOx, SO2, and PM emissions on O3 abatement in Beijing, Shanghai, Guangzhou, and Chengdu would have been avoided if the anthropogenic VOCs emission had been reduced by 24 %, 23 %, 20 %, and 16 %, respectively, from 2013 to 2017. Our analysis revealed that the NOx reduction in recent years has helped to contain the total O3 production in China. However, to reduce O3 levels in major urban and industrial areas, VOC emission controls should be added to the current NOx-SO2-PM policy.

Low-Cost NOx Reduction Retrofit for Pump Scavenged Compressor Engines

1995 ◽  
Vol 117 (4) ◽  
pp. 804-809 ◽  
Author(s):  
E. N. Balles ◽  
R. C. Peoples
Keyword(s):  
Low Cost ◽  
Nox Reduction ◽  
Nox Emission ◽  
Emission Rates ◽  
Natural Gas Pipeline ◽  
Initial Work ◽  
Clean Air ◽  
Nox Control ◽  
Performance Results ◽  
Implementation Plans

The Clean Air Act Amendments of 1990 and the resulting individual State Implementation Plans will require many natural gas pipeline operators to install NOx reduction equipment on existing compressor station engines. A program was undertaken to develop lower cost NOx control options for these engines as compared to traditional techniques. The initial work, described in this paper, focused on the development of a low-cost retrofit package for Cooper-Bessemer GMV and GMV-TF pump scavenged integral compressor engines. The retrofit concept relied on highly dilute combustion to achieve low engine-out NOx emission rates. A significant portion of the effort concentrated on low-cost methods for delivering the required air charge and ignition enhancements to achieve reliable and robust combustion. The prototype retrofit kit has been installed on a GMV-6 in gas compressor service. Performance results showed a 70 percent reduction in NOx emission rates without a corresponding increase in HC emission rates.

Utilization of the MK Combustion Optimization System™ to Maximize Combustion Efficiency in an Environment-First Fashion

2004 ◽  
Author(s):  
David Krzysik
Keyword(s):  
Fine Particles ◽  
Effective Means ◽  
Nox Reduction ◽  
Cost Effective ◽  
Combustion Efficiency ◽  
Contributing Factors ◽  
Nox Formation ◽  
Trade Offs ◽  
Clean Air ◽  
Combustion Optimization

Nitrogen oxide (NOx) emissions discharged into the atmosphere from fossil fuel combustion prove to have adverse effects on the environment and human health. Contributing factors include the formation of acid rain, ozone, degradation of visibility, and inhalable fine particles. In addressing these problems, environmental regulations are becoming more stringent on electric utilities. Low NOx burner (LNB) technology was developed to provide a cost-effective means of complying with the NOx Reduction Program under Title IV of the Clean Air Act Amendments (CAAA) of 1990. Prior to LNB technology, standard burners were designed to rapidly mix the fuel and oxidant, producing high combustion efficiency and large quantities of NOx. Limiting the reaction rate at which the air and fuel mix, particularly during the early stages of combustion, can effectively control NOx formation; however, this rate limitation tends to diminish combustion efficiency and proves to be the compromise of LNB technology. Controlling one aspect or the other can be intuitively easy, but controlling both is challenging and trade-offs are necessary. Identifying a happy medium between the standards of yesterday and today is necessary in the optimization of coal-fired combustion. The ultimate effect will improve commercial availability in an environment-first fashion.

Key Aspects of Assessing Effectiveness and Efficiency of Implementation of the Federal Clean Air Project on the Example of the Comprehensive Emission Reduction Action Plan in Nizhny Tagil

2020 ◽  
pp. 48-60
Author(s):  
SV Yarushin ◽  
DV Kuzmin ◽  
AA Shevchik ◽  
TM Tsepilova ◽  
VB Gurvich ◽  
...  
Keyword(s):  
Emission Reduction ◽  
Action Plan ◽  
Local Population ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Mortality And Morbidity ◽  
Industrial Enterprises ◽  
Clean Air ◽  
Effectiveness And Efficiency ◽  
The Impact

Introduction: Key issues of assessing effectiveness and economic efficiency of implementing the Federal Clean Air Project by public health criteria are considered based on the example of the Comprehensive Emission Reduction Action Plan realized in the city of Nizhny Tagil, Sverdlovsk Region. Materials and methods: We elaborated method approaches and reviewed practical aspects of evaluating measures taken in 2018–2019 at key urban industrial enterprises accounting for 95 % of stationary source emissions. Results: Summary calculations of ambient air pollution and carcinogenic and non-carcinogenic inhalation health risks including residual risks, evaluation of the impact of air quality on urban mortality and morbidity rates, economic assessment of prevented morbidity and premature mortality cases have enabled us not only to estimate health effects but also to develop guidelines for development and implementation of actions aimed at enhancing effectiveness and efficiency of industrial emission reduction in terms of health promotion of the local population. Conclusions: We substantiate proposals for the necessity and sufficiency of taking remedial actions ensuring achievement of acceptable health risk levels as targets of the Comprehensive Emission Reduction Action Plan in Nizhny Tagil until 2024 and beyond.

A Study of the NOx Emission in a Regenerative Industrial Furnace

2001 ◽  
Author(s):  
Qing Jiang ◽  
Chao Zhang
Keyword(s):  
Mixture Fraction ◽  
Combustion Process ◽  
Nox Emission ◽  
Moment Closure ◽  
Combustion Model ◽  
Industrial Furnace ◽  
Low Emission ◽  
Reduction Of Nox ◽  
Closure Method ◽  
Probability Density Function Pdf

Abstract A study of the nitrogen oxides (NOx) emission and combustion process in a gas-fired regenerative, high temperature, low emission industrial furnace has been carried out numerically. The effect of two additives, methanol (CH3OH) and hydrogen peroxide (H2O2), to fuel on the NOx emission has been studied. A moment closure method with the assumed β probability density function (PDF) for mixture fraction is used in the present work to model the turbulent non-premixed combustion process in the furnace. The combustion model is based on the assumption of instantaneous full chemical equilibrium. The results showed that CH3OH is effective in the reduction of NOx in a regenerative industrial furnace. However, H2O2 has no significant effect on the NOx emission.

Water Addition in Diesel Engine Intake for NOx Reduction: Comparison of Modeling and Experiments

2003 ◽  
Author(s):  
Bhaskar Tamma ◽  
Juan Carlos Alvarez ◽  
Aaron J. Simon
Keyword(s):  
Diesel Engine ◽  
Fuel Efficiency ◽  
Nox Reduction ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Nox Emission ◽  
Water Addition ◽  
Predictive Tool ◽  
Fuel Flow ◽  
Influence Of Water

Reduction in emissions, especially NOx has been the main study of various engine researchers in the light of stringent emission norms. To reduce the time and cost involved in testing these technologies, engine thermodynamic cycle predictive tools are used. The present work uses one such predictive tool (GT Power from Gamma Technologies) for predicting the influence of water addition in a turbocharged 6-cylinder diesel engine intake on engine performance and NOx emissions. The experiments for comparison with modeling included the introduction of liquid water in the engine intake stream, between the compressor and intercooler ranging from 0 to 100% of fuel flow rate. NOx emission reduced linearly with water addition with reduction of 63% with less than 1% penalty on fuel efficiency at 100% water addition. The GT Power model predicted the performance within 5% of experimental data and NOx emission within 10% of the experiments.

Sign in / Sign up

Export Citation Format

Share Document