Test results of reducing two stroke motorcycle emissions with new type carburettors and electronic fuel injection systems are presented. Analyses and comparison between different systems are discussed. The adoption o...Test results of reducing two stroke motorcycle emissions with new type carburettors and electronic fuel injection systems are presented. Analyses and comparison between different systems are discussed. The adoption of electronically controlled injection and corresponding electronic control technique is an effective measure of prolonged vitality to improve emissions from two stroke motorcycles. Suggestions about the strategic steps of China′s motorcycle emission control are proposed.展开更多
This paper describes the relation and difference of "emission up to standards" and "total quantity control" ofmain atmospheric pollutants, as well as their legal status. It points out that the tota...This paper describes the relation and difference of "emission up to standards" and "total quantity control" ofmain atmospheric pollutants, as well as their legal status. It points out that the total quantity control is a good approachto solve a problem that environmental quality do not yet reach the requirements in an area where emission concentrationhas came up to standards, or to solve a problem that the interregional transportation of pollutants (e. g. acid rain) arises.And further, it put forward five proposals for the total quantity control.[展开更多
Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze epi- sodes. Changchun City, as the center of Northeast China, has longstanding industry and is an i...Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze epi- sodes. Changchun City, as the center of Northeast China, has longstanding industry and is an important agricultural base. Additionally, Changchun City has a long winter requiring heating of buildings emitting pollution into the air. These factors contribute to the complex- ity of haze pollution in this area. In order to analyze the causes of heavy haze, surface air quality has been monitored from 2013 to 2015. By using satellite and meteorological data, atmospheric pollution status, spatio-temporal variations and formation have been analyzed. Results indicated that the air quality in 88.9% of days exceeding air quality index (AQI) level-1 standard (AQI 〉50) according to the National Ambient Air Quality Standard (NAAQS) of China. Conversely, 33.7% of the days showed a higher level with AQI 〉 100. Ex- treme haze events (AQI 〉 300) occurred frequently during agricultural harvesting period (from October 10 to November 10), intensive winter heating period (from Late-December to February) and period of spring windblown dust (April and May). Most daily concentra- tions of gaseous pollutants, i.e., NO2 (43.8 gg/m3), CO (0.9 mg/m3), SO2 (37.9 gg/m3), and 03 (74.9 gg/m3) were evaluated within level-1 concentration limits of NAAQS standards. However, particulate matter (PM2.5 and PMI0) concentrations (67.3 ~tg/m3and 115.2 ~g/m3, respectively) were significantly higher than their level-1 limits. Severe haze in spring was caused by offsite transported dust and windblown surface soil. Heavy haze periods during fall and winter were mainly formed by intensive emissions of atmospheric pollutants and steady weather conditions (i.e., low wind speed and inversion layer). The overlay emissions of widespread straw burning and coal combustion for heating were the dominant factors contributing to haze in autumn, while intensive coal burning during the coldest time was the primary component of total emissions. In addition, general emissions including automobile exhaust, road and construction dust, residential and industrial activities, have significantly increased in recent years, making heavy haze a more frequent occurrence. There- fore, both improved technological strategies and optimized pollution management on a regional scale are necessary to minimize emis- sions in specified seasons in Changchun City, as well as comprehensive control measures in Northeast China.展开更多
The study of air emission in maritime transportation is new, and the recognition of its importance has been rising in the recent decade. The emissions of CO2, SO2, NO2 and particulate matters from maritime transportat...The study of air emission in maritime transportation is new, and the recognition of its importance has been rising in the recent decade. The emissions of CO2, SO2, NO2 and particulate matters from maritime transportation have contributed to climate change and environmental degradation. Scientifically, analysts still have controversies regarding how to calculate the emissions and how to choose the baseline and methodologies. Three methods are generally used, namely the 'bottom up' approach, the 'top down' approach and the STEEM, which produce very different results, leading to various papers with great uncertainties. This, in turn, resuits in great difficulties to policy makers who attempt to regulate the emissions. A recent technique, the STEEM, is intended to combine the former two methods to reduce their drawbacks. However, the regulations based on its results may increase the costs of shipping companies and cause the competitiveness of the port states and coastal states. Quite a few papers have focused on this area and provided another fresh perspective for the air emission to be incorporated in maritime transportation regulations; these facts deserve more attention. This paper is to review the literature on the debates over air emission calculation, with particular attention given to the STEEM and the refined estimation methods. It also reviews related literature on the economic analysis of maritime transportation emission regulations, and provides an insight into such analysis. At the end of this paper, based on a review and analysis of previous literature, we conclude with the policy indications in the future and work that should be done. As the related regulations in maritime transportation emissions are still at their beginning stage in China, this paper provides specific suggestions on how China should regulate emissions in the maritime transportation sector.展开更多
To better understand the characteristics of air quality and the relationship between the chemical composition evolution and source variation,an intensive atmospheric campaign was conducted in Tianjin,a megacity of the...To better understand the characteristics of air quality and the relationship between the chemical composition evolution and source variation,an intensive atmospheric campaign was conducted in Tianjin,a megacity of the North China Plain,from 10 February to 6 March 2015.There were 20 days exceeding the threshold value of secondary Chinese Ambient Air Quality Standards for PM2.5(75 μg m-3,daily average over 24 h)during the study period.Five air pollution episodes were selected for investigation.During the pre-holiday pollution episode,NH^+_4,NO^-_3,and SO^(2-)_4 were more abundant,indicating that air pollution was caused by motor vehicle exhaust emissions and coal consumption under unfavorable meteorological conditions.During Chinese Lunar New Year's Eve,widespread use of fireworks resulted in extremely high aerosol concentrations.Firework displays caused increases in K+ and also enrichment of SO^(2-)_4 relative to NO^-_3.The holiday pollution episode was caused by regional transport,characterized by abundant SO^(2-)_4 and NH^+_4.In addition,the aging processes of the particles from fireworks discharge played an important role in the formation of NO-3and SO^(2-)_4.The Lantern Festival episode was characterized by a transition from the enrichment of K+ to secondary inorganic ions(NO^-_3,SO^(2-)_4,and NH^+_4).The results of this study are useful for a detailed understanding of the variation in atmospheric compositions and sources caused by anthropogenic activity,and highlight the importance of controlling intensive fireworks discharge.展开更多
The paper describes numerical and experimental study on reduction of NOx emissions in a 600 MW tangentially fired boiler furnace under different operating conditions. A simplified NOX formation mechanism model, along ...The paper describes numerical and experimental study on reduction of NOx emissions in a 600 MW tangentially fired boiler furnace under different operating conditions. A simplified NOX formation mechanism model, along with the gas-particle multiphase flow model, is adopted. The prediction yields encouraging results as compared to experimental data.展开更多
On account of the background of China's "new normal" characterized by slower economic growth, this paper analyses the low-carbon economy status quo in the Beijing-Tianjin-Hebei region and empirically inv...On account of the background of China's "new normal" characterized by slower economic growth, this paper analyses the low-carbon economy status quo in the Beijing-Tianjin-Hebei region and empirically investigates the relationship between carbon dioxide(CO_2) emissions and its various factors for China's Beijing-Tianjin-Hebei region using panel data econometric technique. We find evidence of existence of Environmental Kuznets Curve. Results also show that economic scale, industrial structure, and urbanization rate are crucial factors to promote CO_2emissions. However, technological progress, especially the domestic independent research and development, plays a key role in C0_2 emissions abatement. Next, we further analyze the correlation between each subregion and various factors according to Grey Relation Analysis. Thereby,our findings provide important implications for policymakers in air pollution control and C0_2 emissions reduction for this region.展开更多
China's new Atmospheric Pollutant Emission Standard for Thermal Power Plants has been made the most stringent atmospheric pollutant emission limit in the world,with the intensified control of nitrogen oxides in th...China's new Atmospheric Pollutant Emission Standard for Thermal Power Plants has been made the most stringent atmospheric pollutant emission limit in the world,with the intensified control of nitrogen oxides in the air pollutants emitted by thermal power plants,the tightened limit on the emission of sulfur dioxide,and the widened range of control including mercury and other compounds discharge.The adoption of the new standard will considerably impact the survival and development of power plants,even the whole economy of the nation.While implementing all the policies and measures on emission reduction issued by the State to fulfill political,social,and economic responsibilities,China Huadian Corporation,one of the leading state-owned power generation groups,is actively exploring the green and low-carbon path for the sound and rapid development of the group.展开更多
Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), on the temporal variations of the annual water discharge at the Liji...Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), on the temporal variations of the annual water discharge at the Lijin station in the Huanghe (Yellow) River and at the Datong station in the Changjiang (Yangtze) River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis (EMD- MESA) method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers.展开更多
The largest urban areas of Mexico cities have witnessed high levels of air pollution in the past few decades. The most important air pollutants are ozone and paniculate matter with levels that are still far above curr...The largest urban areas of Mexico cities have witnessed high levels of air pollution in the past few decades. The most important air pollutants are ozone and paniculate matter with levels that are still far above current air quality standard. In this work we studied exhaust and evaporative emissions of Mexico City metropolitan area (MAMC) vehicles using fuels in which sulfur content was varied from 89×10^-6 to 817×10^-6, and calculated the ozone forming potential of emissions as well as the specific reactivity of the exhaust for each average fleet-fuel combinations. Data on emission levels were compared to those obtained in 2000 for the same vintage of vehicles. The almost twofold increase in emissions found could be due to degradation of the exhaust emissions control systems.展开更多
The Emission Standards of Air Pollutants from Thermal Power Plants (GB 13223-2011) prescribe a stricter limitation to air pollutants than ever before. As set in the new emission standard, the limitations of SO2 and NO...The Emission Standards of Air Pollutants from Thermal Power Plants (GB 13223-2011) prescribe a stricter limitation to air pollutants than ever before. As set in the new emission standard, the limitations of SO2 and NOX for sensitive areas under normal conditions are 50 mg/m3 and 100 mg/m3, respectively. The objective analysis and suggestions are proposed. The recent status and operational experience of desulfurization and denitrification equipment are discussed. From the discussions, thermal power plants face a huge challenge to satisfy the new emission standards. For further reducing of the emission concentrations of SO2 and NOX, three methods were introduced, including: seriously implementing the emission standards, improving treatment equipment, and increasing the efficiencies of desulfurization and denitrification.展开更多
Based on the statistics from the China Statistical Yearbook (2000-2009) on environment and methods recommended by the IPCC, the amounts of greenhouse gas (GHG) emissions from domestic and industrial sewage treatme...Based on the statistics from the China Statistical Yearbook (2000-2009) on environment and methods recommended by the IPCC, the amounts of greenhouse gas (GHG) emissions from domestic and industrial sewage treatment in China are estimated for the period of 2003-2009. CO2 emissions per capita from sewage treatment plants are also analyzed. The results show that the GHG emissions from sewage treatment plants increased steadily from 2003 to 2009; N20 emissions from domestic sewage are the major source of the total GHG emissions from domestic sewage; CH4 emissions from domestic sewage increase with the greatest speed; CH4 emissions from paper and pulp industry are the major source of industrial sewage emissions; CO2 emissions per capita increase constantly from 2003 to 2009.展开更多
A decomposition model was applied to study the resource-saving and environment-friendly effects of air pollutant emissions(taking industrial SO2 emission as an example) in China.From the results,it is found that 38.93...A decomposition model was applied to study the resource-saving and environment-friendly effects of air pollutant emissions(taking industrial SO2 emission as an example) in China.From the results,it is found that 38.93% and 61.07% are contributed to environment-friendly and resource-saving effects,respectively,by the dramatic decrease in industrial SO2 emission density(nearly 70% from 2001 to 2010).This indicates that China has achieved important progress during the 11th FYP(five-year plan) compared with the 10th FYP.A simultaneous equations model was also employed to analyze the influencing factors by using data from 30 provinces in China.The results imply that the influence of environmental regulation on environment-friendly effect is not obvious during the 10th FYP but obvious during the 11th FYP.Thus,the government should continue promoting the environment-friendly effect by further enhancing environmental regulation and strengthening the role of environmental management.展开更多
Air pollution in modern city and industrial zones has become a serious public concern in recent years in China. Significance of air quality assessment and emission control strategy design is increasing. Most studies i...Air pollution in modern city and industrial zones has become a serious public concern in recent years in China. Significance of air quality assessment and emission control strategy design is increasing. Most studies in China focus on particulate matter(PM), especially PM2.5, while few account for photochemical secondary air pollutions represented by ozone(O3). In this paper, a procedure for air quality simulation with comprehensive air quality model with extensions(CAMx) is demonstrated for studying the photochemical process and ozone generation in the troposphere. As a case study, the CAMx photochemical grid model is used to model ozone over southern part of Beijing city in winter, 2011. The input parameters to CAMx include emission sources, meteorology field data, terrain definition, photolysis status, initial and boundary conditions. The simulation results are verified by theoretical analysis of the ozone generation tendency. The simulated variation tendency of domain-wide average value of hourly ozone concentration coincides reasonably well with the theoretical analysis on the atmospheric photochemical process, demonstrating the effectiveness of the procedure. An integrated model system that cooperates with CAMx will be established in our future work.展开更多
Vehicle emissions are one of the major sources of urban air pollution and are also called mobile source emissions. A large amount of gross vehicle emissions is generated by vehicles commuting between residential homes...Vehicle emissions are one of the major sources of urban air pollution and are also called mobile source emissions. A large amount of gross vehicle emissions is generated by vehicles commuting between residential homes and the workplace. Homebuyers generally prefer to purchase residential houses that are relatively less expensive, albeit at the cost of relatively longer commuting times. Consumers usually consider additional travel time, fuel consumption, and other personally concerned factors, with less apprehension about the extra air pollution possibly generated. In cities with populations between 15,000 and 1,000,000, an increase of one additional minute of average commuting time is associated with a reduction of 1.9 dollars in housing price per square foot (p-value: 0.038). To account for the generation of additional air pollution, this paper numerically characterizes factors related to air pollutants caused by additional travel time due to housing prices. Air pollutants such as CO, CO2, NO2, NO, NOx and SO2 as well as fuel consumption were estimated by MOVES (motor vehicle emissions simulator). The results will be a useful reference to generate recommendations for more efficient reduction of mobile source air pollution in metropolitan areas through joint efforts by government, agencies, the public, and industry from multiple fields including environment protection, land use, housing markets, transportation management, and law enforcement.展开更多
Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People's Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, C...Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People's Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China's railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China's railway transportation.展开更多
Using air pollution detecting equipments ITX, ATX620 and IBRID-MX6 Multi gas monitors a pioneer research was carried out to assess the levels of the exhausted gas emission in double-floored car parks of the Holy Proph...Using air pollution detecting equipments ITX, ATX620 and IBRID-MX6 Multi gas monitors a pioneer research was carried out to assess the levels of the exhausted gas emission in double-floored car parks of the Holy Prophet Mosque in Al-Madinah A l-Munawarah from early 12:00 to 14:00 of Friday and from 19:00 to 22:30 at holy month, Ramadan. The percentage of both carbon monoxide (CO) and nitrogen dioxide (NO2) had significantly increased (p 〈 0.05-0.005). The peak levels of these air pollutants were between 13:15-13:20 during Fridays. The increase in the emission of these exhausted gases was concomitant with the significant decrease (p 〈 0.05) in oxygen (02) levels but the latter recovered its levels after 13:20 hours. The arithmetic total mean density of vehicle per minute (vpm) at Salam Road, the busiest road of Al-Madinah, during hours (07:00-09:00), (13:00-15:00) and (17:00-19:00) of both Friday and Saturdays respectively were (8/45, 16/40 and 36/43). The increase in air pollution has been attributed to a dramatic increase in number of public cars use the car parks during these times, the consequent congestion at entries, the excess or/and poor consumption of fuels being utilized and the inadequate ventilation.展开更多
The atmospheric mercury pollution in Beijing is a serious problem.Atmospheric mercury has three sources:natural emission,anthropogenic emission and previously deposited mercury reemission or recycling,composing elemen...The atmospheric mercury pollution in Beijing is a serious problem.Atmospheric mercury has three sources:natural emission,anthropogenic emission and previously deposited mercury reemission or recycling,composing elemental mercury,divalent mercury and particulate-phase mercury.Many studies showed that mercury in Beijing's air was higher than the general level of mercury concentration in the atmosphere.Mercury emission sources were discussed.Industrial emissions,coal burning,vehicle exhaust emissions and waste incineration were thought to be the main sources of atmospheric mercury pollution in Beijing.And also meteorology has an effect on atmospheric mercury concentration in Beijing.Measures have been taken to control the emission of mercury into the air in recent years.展开更多
EVs (electric vehicles) have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the ...EVs (electric vehicles) have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the high adoption of EVs will impose a burden on the power system, especially for neighborhood level network. In this paper, we propose a mixed control framework for EV charging scheduling to mitigate its impact on the power network. A metric for modeling customer's satisfaction is also proposed to compare the user satisfaction for different algorithms. The impacts of the proposed algorithms on EV charging cost, EV penetration and peak power reduction are evaluated with real data for a neighborhood level network. The simulation results demonstrate the effectiveness of the proposed algorithms.展开更多
文摘Test results of reducing two stroke motorcycle emissions with new type carburettors and electronic fuel injection systems are presented. Analyses and comparison between different systems are discussed. The adoption of electronically controlled injection and corresponding electronic control technique is an effective measure of prolonged vitality to improve emissions from two stroke motorcycles. Suggestions about the strategic steps of China′s motorcycle emission control are proposed.
文摘This paper describes the relation and difference of "emission up to standards" and "total quantity control" ofmain atmospheric pollutants, as well as their legal status. It points out that the total quantity control is a good approachto solve a problem that environmental quality do not yet reach the requirements in an area where emission concentrationhas came up to standards, or to solve a problem that the interregional transportation of pollutants (e. g. acid rain) arises.And further, it put forward five proposals for the total quantity control.[
基金Under the auspices of National Key Research and Development Project(No.2017YFC0212300)Youth Innovation Promotion Association CAS(No.2017275)Frontier Science Research Plan CAS(No.QYZDB-SSW-DQC045)
文摘Northeast China has been reported as having serious air pollution in China with increasing occurrences of severe haze epi- sodes. Changchun City, as the center of Northeast China, has longstanding industry and is an important agricultural base. Additionally, Changchun City has a long winter requiring heating of buildings emitting pollution into the air. These factors contribute to the complex- ity of haze pollution in this area. In order to analyze the causes of heavy haze, surface air quality has been monitored from 2013 to 2015. By using satellite and meteorological data, atmospheric pollution status, spatio-temporal variations and formation have been analyzed. Results indicated that the air quality in 88.9% of days exceeding air quality index (AQI) level-1 standard (AQI 〉50) according to the National Ambient Air Quality Standard (NAAQS) of China. Conversely, 33.7% of the days showed a higher level with AQI 〉 100. Ex- treme haze events (AQI 〉 300) occurred frequently during agricultural harvesting period (from October 10 to November 10), intensive winter heating period (from Late-December to February) and period of spring windblown dust (April and May). Most daily concentra- tions of gaseous pollutants, i.e., NO2 (43.8 gg/m3), CO (0.9 mg/m3), SO2 (37.9 gg/m3), and 03 (74.9 gg/m3) were evaluated within level-1 concentration limits of NAAQS standards. However, particulate matter (PM2.5 and PMI0) concentrations (67.3 ~tg/m3and 115.2 ~g/m3, respectively) were significantly higher than their level-1 limits. Severe haze in spring was caused by offsite transported dust and windblown surface soil. Heavy haze periods during fall and winter were mainly formed by intensive emissions of atmospheric pollutants and steady weather conditions (i.e., low wind speed and inversion layer). The overlay emissions of widespread straw burning and coal combustion for heating were the dominant factors contributing to haze in autumn, while intensive coal burning during the coldest time was the primary component of total emissions. In addition, general emissions including automobile exhaust, road and construction dust, residential and industrial activities, have significantly increased in recent years, making heavy haze a more frequent occurrence. There- fore, both improved technological strategies and optimized pollution management on a regional scale are necessary to minimize emis- sions in specified seasons in Changchun City, as well as comprehensive control measures in Northeast China.
基金supported by the Program for New Century Excellent Talents in University (NCET), NCET-07-0777
文摘The study of air emission in maritime transportation is new, and the recognition of its importance has been rising in the recent decade. The emissions of CO2, SO2, NO2 and particulate matters from maritime transportation have contributed to climate change and environmental degradation. Scientifically, analysts still have controversies regarding how to calculate the emissions and how to choose the baseline and methodologies. Three methods are generally used, namely the 'bottom up' approach, the 'top down' approach and the STEEM, which produce very different results, leading to various papers with great uncertainties. This, in turn, resuits in great difficulties to policy makers who attempt to regulate the emissions. A recent technique, the STEEM, is intended to combine the former two methods to reduce their drawbacks. However, the regulations based on its results may increase the costs of shipping companies and cause the competitiveness of the port states and coastal states. Quite a few papers have focused on this area and provided another fresh perspective for the air emission to be incorporated in maritime transportation regulations; these facts deserve more attention. This paper is to review the literature on the debates over air emission calculation, with particular attention given to the STEEM and the refined estimation methods. It also reviews related literature on the economic analysis of maritime transportation emission regulations, and provides an insight into such analysis. At the end of this paper, based on a review and analysis of previous literature, we conclude with the policy indications in the future and work that should be done. As the related regulations in maritime transportation emissions are still at their beginning stage in China, this paper provides specific suggestions on how China should regulate emissions in the maritime transportation sector.
基金supported by the Beijing Natural Science Foundation[grant number 8142034]Strategic Priority Research Program(B)of the Chinese Academy of Sciences[grant numbers XDB0502050 and XDB05030203]
文摘To better understand the characteristics of air quality and the relationship between the chemical composition evolution and source variation,an intensive atmospheric campaign was conducted in Tianjin,a megacity of the North China Plain,from 10 February to 6 March 2015.There were 20 days exceeding the threshold value of secondary Chinese Ambient Air Quality Standards for PM2.5(75 μg m-3,daily average over 24 h)during the study period.Five air pollution episodes were selected for investigation.During the pre-holiday pollution episode,NH^+_4,NO^-_3,and SO^(2-)_4 were more abundant,indicating that air pollution was caused by motor vehicle exhaust emissions and coal consumption under unfavorable meteorological conditions.During Chinese Lunar New Year's Eve,widespread use of fireworks resulted in extremely high aerosol concentrations.Firework displays caused increases in K+ and also enrichment of SO^(2-)_4 relative to NO^-_3.The holiday pollution episode was caused by regional transport,characterized by abundant SO^(2-)_4 and NH^+_4.In addition,the aging processes of the particles from fireworks discharge played an important role in the formation of NO-3and SO^(2-)_4.The Lantern Festival episode was characterized by a transition from the enrichment of K+ to secondary inorganic ions(NO^-_3,SO^(2-)_4,and NH^+_4).The results of this study are useful for a detailed understanding of the variation in atmospheric compositions and sources caused by anthropogenic activity,and highlight the importance of controlling intensive fireworks discharge.
基金Supported by the National Science Foundation of Zhejiang Province.
文摘The paper describes numerical and experimental study on reduction of NOx emissions in a 600 MW tangentially fired boiler furnace under different operating conditions. A simplified NOX formation mechanism model, along with the gas-particle multiphase flow model, is adopted. The prediction yields encouraging results as compared to experimental data.
基金supported by National Social Science Foundation Project of China-A study on the Long-term Mechanism and Policy of Promoting the Construction of Ecological Civilization with Green Technological Innovation in China:[Grant Number 14AJL017]
文摘On account of the background of China's "new normal" characterized by slower economic growth, this paper analyses the low-carbon economy status quo in the Beijing-Tianjin-Hebei region and empirically investigates the relationship between carbon dioxide(CO_2) emissions and its various factors for China's Beijing-Tianjin-Hebei region using panel data econometric technique. We find evidence of existence of Environmental Kuznets Curve. Results also show that economic scale, industrial structure, and urbanization rate are crucial factors to promote CO_2emissions. However, technological progress, especially the domestic independent research and development, plays a key role in C0_2 emissions abatement. Next, we further analyze the correlation between each subregion and various factors according to Grey Relation Analysis. Thereby,our findings provide important implications for policymakers in air pollution control and C0_2 emissions reduction for this region.
文摘China's new Atmospheric Pollutant Emission Standard for Thermal Power Plants has been made the most stringent atmospheric pollutant emission limit in the world,with the intensified control of nitrogen oxides in the air pollutants emitted by thermal power plants,the tightened limit on the emission of sulfur dioxide,and the widened range of control including mercury and other compounds discharge.The adoption of the new standard will considerably impact the survival and development of power plants,even the whole economy of the nation.While implementing all the policies and measures on emission reduction issued by the State to fulfill political,social,and economic responsibilities,China Huadian Corporation,one of the leading state-owned power generation groups,is actively exploring the green and low-carbon path for the sound and rapid development of the group.
基金Supported by the National Basic Research Program of China(973 Program)(No.2010CB951202)the National Natural Science Foundation of China(Nos.41376055,41030856)
文摘Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), on the temporal variations of the annual water discharge at the Lijin station in the Huanghe (Yellow) River and at the Datong station in the Changjiang (Yangtze) River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis (EMD- MESA) method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers.
文摘The largest urban areas of Mexico cities have witnessed high levels of air pollution in the past few decades. The most important air pollutants are ozone and paniculate matter with levels that are still far above current air quality standard. In this work we studied exhaust and evaporative emissions of Mexico City metropolitan area (MAMC) vehicles using fuels in which sulfur content was varied from 89×10^-6 to 817×10^-6, and calculated the ozone forming potential of emissions as well as the specific reactivity of the exhaust for each average fleet-fuel combinations. Data on emission levels were compared to those obtained in 2000 for the same vintage of vehicles. The almost twofold increase in emissions found could be due to degradation of the exhaust emissions control systems.
文摘The Emission Standards of Air Pollutants from Thermal Power Plants (GB 13223-2011) prescribe a stricter limitation to air pollutants than ever before. As set in the new emission standard, the limitations of SO2 and NOX for sensitive areas under normal conditions are 50 mg/m3 and 100 mg/m3, respectively. The objective analysis and suggestions are proposed. The recent status and operational experience of desulfurization and denitrification equipment are discussed. From the discussions, thermal power plants face a huge challenge to satisfy the new emission standards. For further reducing of the emission concentrations of SO2 and NOX, three methods were introduced, including: seriously implementing the emission standards, improving treatment equipment, and increasing the efficiencies of desulfurization and denitrification.
基金supported by the GEF/UNDP Second National Communication on Climate Change of China--China’s inventory of GHG emissions from wastewater/sewage treatment subproject
文摘Based on the statistics from the China Statistical Yearbook (2000-2009) on environment and methods recommended by the IPCC, the amounts of greenhouse gas (GHG) emissions from domestic and industrial sewage treatment in China are estimated for the period of 2003-2009. CO2 emissions per capita from sewage treatment plants are also analyzed. The results show that the GHG emissions from sewage treatment plants increased steadily from 2003 to 2009; N20 emissions from domestic sewage are the major source of the total GHG emissions from domestic sewage; CH4 emissions from domestic sewage increase with the greatest speed; CH4 emissions from paper and pulp industry are the major source of industrial sewage emissions; CO2 emissions per capita increase constantly from 2003 to 2009.
基金Project(201009066)supported by the R&D Special Fund for Public Welfare of the Ministry of Finance and Ministry of Science and Technology of China
文摘A decomposition model was applied to study the resource-saving and environment-friendly effects of air pollutant emissions(taking industrial SO2 emission as an example) in China.From the results,it is found that 38.93% and 61.07% are contributed to environment-friendly and resource-saving effects,respectively,by the dramatic decrease in industrial SO2 emission density(nearly 70% from 2001 to 2010).This indicates that China has achieved important progress during the 11th FYP(five-year plan) compared with the 10th FYP.A simultaneous equations model was also employed to analyze the influencing factors by using data from 30 provinces in China.The results imply that the influence of environmental regulation on environment-friendly effect is not obvious during the 10th FYP but obvious during the 11th FYP.Thus,the government should continue promoting the environment-friendly effect by further enhancing environmental regulation and strengthening the role of environmental management.
文摘Air pollution in modern city and industrial zones has become a serious public concern in recent years in China. Significance of air quality assessment and emission control strategy design is increasing. Most studies in China focus on particulate matter(PM), especially PM2.5, while few account for photochemical secondary air pollutions represented by ozone(O3). In this paper, a procedure for air quality simulation with comprehensive air quality model with extensions(CAMx) is demonstrated for studying the photochemical process and ozone generation in the troposphere. As a case study, the CAMx photochemical grid model is used to model ozone over southern part of Beijing city in winter, 2011. The input parameters to CAMx include emission sources, meteorology field data, terrain definition, photolysis status, initial and boundary conditions. The simulation results are verified by theoretical analysis of the ozone generation tendency. The simulated variation tendency of domain-wide average value of hourly ozone concentration coincides reasonably well with the theoretical analysis on the atmospheric photochemical process, demonstrating the effectiveness of the procedure. An integrated model system that cooperates with CAMx will be established in our future work.
基金The authors acknowledge that this research is supported in part by the United States Tier 1 University Transportation Center TranLIVE # DTRT12GUTC17/KLK900-SB-003, and the NSF (National Science Foundation) under grants #1137732 The opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding agencies.
文摘Vehicle emissions are one of the major sources of urban air pollution and are also called mobile source emissions. A large amount of gross vehicle emissions is generated by vehicles commuting between residential homes and the workplace. Homebuyers generally prefer to purchase residential houses that are relatively less expensive, albeit at the cost of relatively longer commuting times. Consumers usually consider additional travel time, fuel consumption, and other personally concerned factors, with less apprehension about the extra air pollution possibly generated. In cities with populations between 15,000 and 1,000,000, an increase of one additional minute of average commuting time is associated with a reduction of 1.9 dollars in housing price per square foot (p-value: 0.038). To account for the generation of additional air pollution, this paper numerically characterizes factors related to air pollutants caused by additional travel time due to housing prices. Air pollutants such as CO, CO2, NO2, NO, NOx and SO2 as well as fuel consumption were estimated by MOVES (motor vehicle emissions simulator). The results will be a useful reference to generate recommendations for more efficient reduction of mobile source air pollution in metropolitan areas through joint efforts by government, agencies, the public, and industry from multiple fields including environment protection, land use, housing markets, transportation management, and law enforcement.
基金supported by Climate Change Special Project of China Meteorological Administration(No CCSF2011-14)
文摘Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People's Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China's railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China's railway transportation.
文摘Using air pollution detecting equipments ITX, ATX620 and IBRID-MX6 Multi gas monitors a pioneer research was carried out to assess the levels of the exhausted gas emission in double-floored car parks of the Holy Prophet Mosque in Al-Madinah A l-Munawarah from early 12:00 to 14:00 of Friday and from 19:00 to 22:30 at holy month, Ramadan. The percentage of both carbon monoxide (CO) and nitrogen dioxide (NO2) had significantly increased (p 〈 0.05-0.005). The peak levels of these air pollutants were between 13:15-13:20 during Fridays. The increase in the emission of these exhausted gases was concomitant with the significant decrease (p 〈 0.05) in oxygen (02) levels but the latter recovered its levels after 13:20 hours. The arithmetic total mean density of vehicle per minute (vpm) at Salam Road, the busiest road of Al-Madinah, during hours (07:00-09:00), (13:00-15:00) and (17:00-19:00) of both Friday and Saturdays respectively were (8/45, 16/40 and 36/43). The increase in air pollution has been attributed to a dramatic increase in number of public cars use the car parks during these times, the consequent congestion at entries, the excess or/and poor consumption of fuels being utilized and the inadequate ventilation.
文摘The atmospheric mercury pollution in Beijing is a serious problem.Atmospheric mercury has three sources:natural emission,anthropogenic emission and previously deposited mercury reemission or recycling,composing elemental mercury,divalent mercury and particulate-phase mercury.Many studies showed that mercury in Beijing's air was higher than the general level of mercury concentration in the atmosphere.Mercury emission sources were discussed.Industrial emissions,coal burning,vehicle exhaust emissions and waste incineration were thought to be the main sources of atmospheric mercury pollution in Beijing.And also meteorology has an effect on atmospheric mercury concentration in Beijing.Measures have been taken to control the emission of mercury into the air in recent years.
文摘EVs (electric vehicles) have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the high adoption of EVs will impose a burden on the power system, especially for neighborhood level network. In this paper, we propose a mixed control framework for EV charging scheduling to mitigate its impact on the power network. A metric for modeling customer's satisfaction is also proposed to compare the user satisfaction for different algorithms. The impacts of the proposed algorithms on EV charging cost, EV penetration and peak power reduction are evaluated with real data for a neighborhood level network. The simulation results demonstrate the effectiveness of the proposed algorithms.