scholarly journals Contributions of Trans-boundary Transport to the Summertime Air Quality in Beijing, China

2016 ◽  
Author(s):  
Jiarui Wu ◽  
Guohui Li ◽  
Junji Cao ◽  
Naifang Bei ◽  
Yichen Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Control Strategies ◽  
Dominant Role ◽  
Fine Particulate Matter ◽  
Temporal Variations ◽  
Pollutant Emissions ◽  
Beijing China ◽  
Local Emissions ◽  
Factor Separation ◽  
Good Agreement

Abstract. In the present study, the WRF-CHEM model is used to evaluate the contributions of trans-boundary transport to the air quality in Beijing during a persistent air pollution episode from 5 to 14 July 2015 in Beijing-Tianjin-Hebei (BTH), China. Generally, the predicted temporal variations and spatial distributions of PM2.5 (fine particulate matter), O3 (ozone), and NO2 are in good agreement with observations in BTH. The WRF-CHEM model also reproduces reasonably well the temporal variations of aerosol species compared to measurements in Beijing. The factor separation approach is employed to evaluate the contributions of trans-boundary transport of emissions outside of Beijing to the PM2.5 and O3 levels in Beijing. On average, in the afternoon during the simulation episode, the pure local emissions contribute 22.4 % to the O3 level in Beijing, less than 36.6 % from pure emissions outside of Beijing. The O3 concentrations in Beijing are decreased by 5.1 % in the afternoon due to interactions of local emissions with those outside of Beijing. The pure emissions outside of Beijing play a dominant role in the PM2.5 level in Beijing, with a contribution of 61.5 %, much more than 13.7 % from pure Beijing local emissions. The emissions interactions enhance the PM2.5 concentrations in Beijing, with a contribution of 5.9 %. Therefore, the air quality in Beijing is primarily determined by the trans-boundary transport of emissions outside of Beijing during summertime, showing that the cooperation with neighboring provinces to mitigate pollutant emissions is a key for Beijing to improve air quality. Considering the uncertainties in the emission inventory and the meteorological field simulations, further studies need to be performed to improve the WRF-CHEM model simulations to reasonably evaluate trans-boundary transport contributions to the air quality in Beijing for supporting the design and implementation of emission control strategies.

scholarly journals Contributions of trans-boundary transport to summertime air quality in Beijing, China

2017 ◽  
Vol 17 (3) ◽  
pp. 2035-2051 ◽  
Author(s):  
Jiarui Wu ◽  
Guohui Li ◽  
Junji Cao ◽  
Naifang Bei ◽  
Yichen Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Dominant Role ◽  
Fine Particulate Matter ◽  
Temporal Variations ◽  
Pollutant Emissions ◽  
Fine Particulate ◽  
Beijing China ◽  
Local Emissions ◽  
Factor Separation ◽  
Good Agreement

Abstract. In the present study, the WRF-CHEM model is used to evaluate the contributions of trans-boundary transport to the air quality in Beijing during a persistent air pollution episode from 5 to 14 July 2015 in Beijing–Tianjin–Hebei (BTH), China. Generally, the predicted temporal variations and spatial distributions of PM2.5 (fine particulate matter), O3 (ozone), and NO2 are in good agreement with observations in BTH. The WRF-CHEM model also reproduces reasonably well the temporal variations of aerosol species compared to measurements in Beijing. The factor separation approach is employed to evaluate the contributions of trans-boundary transport of non-Beijing emissions to the PM2.5 and O3 levels in Beijing. On average, in the afternoon during the simulation episode, the local emissions contribute 22.4 % to the O3 level in Beijing, less than 36.6 % from non-Beijing emissions. The O3 concentrations in Beijing are decreased by 5.1 % in the afternoon due to interactions between local and non-Beijing emissions. The non-Beijing emissions play a dominant role in the PM2.5 level in Beijing, with a contribution of 61.5 %, much higher than 13.7 %, from Beijing local emissions. The emission interactions between local and non-Beijing emissions enhance the PM2.5 concentrations in Beijing, with a contribution of 5.9 %. Therefore, the air quality in Beijing is generally determined by the trans-boundary transport of non-Beijing emissions during summertime, showing that the cooperation with neighboring provinces to mitigate pollutant emissions is key for Beijing to improve air quality.

scholarly journals Contributions of residential coal combustion to the air quality in Beijing-Tianjin-Hebei (BTH), China: A case study

2018 ◽  
Author(s):  
Xia Li ◽  
Jiarui Wu ◽  
Miriam Elser ◽  
Junji Cao ◽  
Tian Feng ◽  
...  
Keyword(s):  
Air Quality ◽  
Coal Combustion ◽  
Fine Particulate Matter ◽  
Clean Energy ◽  
Temporal Variations ◽  
Haze Formation ◽  
Surrounding Areas ◽  
Residential Coal ◽  
Good Agreement

Abstract. In the present study, the WRF-CHEM model is used to evaluate contributions of the residential coal combustion (RCC) emission to the air quality in Beijing-Tianjin-Hebei (BTH) during persistent air pollution episodes from 9 to 25 January 2014. In general, the predicted temporal variations and spatial distributions of the air pollutants mass concentrations are in good agreement with observations at monitoring sites in BTH. The WRF-CHEM model also reasonably well reproduces the temporal variations of aerosol species compared with the AMS measurements in Beijing. The RCC emission plays an important role in the haze formation in BTH, contributing about 23.1 % of PM2.5 (fine particulate matter) and 42.6 % of SO2 during the simulation period on average. Organic aerosols dominate PM2.5 from the RCC emission, with a contribution of 42.8 %, followed by sulfate (17.1 %). The air quality in Beijing is remarkably improved when the RCC emission in BTH and its surrounding areas is excluded in simulations, with a 30 % decrease of PM2.5 concentrations. However, when only the RCC emission in Beijing is excluded, the Beijing's PM2.5 level is decreased by 18.0 % on average. Our results suggest that implementation of the residential coal replacement by clean energy sources in Beijing is beneficial to the Beijing's air quality, but is not expected to bring back the blue sky to Beijing. Should the residential coal replacement be carried out in BTH and its surrounding areas, the air quality in Beijing would be improved remarkably. Further studies need be conducted considering the uncertainties in the emission inventory and meteorological fields.

scholarly journals Chemical characteristics of inorganic ammonium salts in PM<sub>2.5</sub> in the atmosphere of Beijing (China)

2011 ◽  
Vol 11 (21) ◽  
pp. 10803-10822 ◽  
Author(s):  
A. Ianniello ◽  
F. Spataro ◽  
G. Esposito ◽  
I. Allegrini ◽  
M. Hu ◽  
...  
Keyword(s):  
Fine Particulate Matter ◽  
Early Morning ◽  
Temporal Variations ◽  
Diurnal Variations ◽  
Local Source ◽  
Particle Interactions ◽  
Atmospheric Conditions ◽  
Fine Particulate ◽  
Annular Denuder ◽  
Beijing China

Abstract. The atmospheric concentrations of gaseous HNO3, HCl and NH3 and their relative salts have been measured during two field campaigns in the winter and in the summer of 2007 at Beijing (China), as part of CAREBEIJING (Campaigns of Air Quality Research in Beijing and Surrounding Region). In this study, annular denuder technique used with integration times of 2 and 24h to collect inorganic and soluble PM2.5 without interferences from gas–particle and particle–particle interactions. The results were discussed from the standpoint of temporal and diurnal variations and meteorological effects. Fine particulate Cl−, NH4+ and SO42− exhibited distinct temporal variations, while fine particulate NO3− did not show much variation with respect to season. Daily mean concentrations of fine particulate NH4+ and SO42− were higher during summer (12.30 μg m−3 and 18.24 μg m−3, respectively) than during winter (6.51 μg m−3 and 7.50 μg m−3, respectively). Daily mean concentrations of fine particulate Cl− were higher during winter (2.94 μg m−3) than during summer (0.79 μg m−3), while fine particulate NO3− showed similar both in winter (8.38 μg m−3) and in summer (9.62 μg m−3) periods. The presence of large amounts of fine particulate NO3− even in summer are due to higher local and regional concentrations of NH3 in the atmosphere available to neutralize H2SO4 and HNO3, which is consistent with the observation that the measured particulate species were neutralized. The composition of fine particulate matter indicated the domination of (NH4)2SO4 during winter and summer periods. In addition, the high relative humidity conditions in summer period seemed to dissolve a significant fraction of HNO3 and NH3 enhancing fine particulate NO3− and NH4+ in the atmosphere. All measured particulate species showed diurnal similar patterns during the winter and summer periods with higher peaks in the early morning, especially in summer, when humid and stable atmospheric conditions occurred. These diurnal variations were affected by wind direction suggesting regional and local source influences. The fine particulate species were correlated with NOx and PM2.5, supporting the hypothesis that traffic may be also an important source of secondary particles.

Comparison of Modeled-to-Monitored PM2.5 Exposure Concentrations Resulting from Transportation Emissions in a Near-Road Community

2020 ◽  
Vol 2674 (12) ◽  
pp. 130-143
Author(s):  
Mayra Chavez ◽  
Wen-Whai Li
Keyword(s):  
Air Quality ◽  
Meteorological Data ◽  
Temporal Variations ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Spatial And Temporal Variations ◽  
Quality Data ◽  
Background Concentrations ◽  
Regional Background ◽  
Transportation Emissions

Residents living in near-road communities are exposed to traffic-related air pollutants, which can adversely affect their health. Near-road communities are expected to observe significant spatial and temporal variations in pollutant concentrations. Determining these variations in the surrounding areas can help raise awareness among government agencies of these underserved communities living near highways. This study conducted traffic and air quality measurements along with emission and dispersion modeling of the exposure to transportation emissions of a near-road urban community adjacent to the US 54 highway (US 54), with annual average daily traffic (AADT) of 107,237. The objectives of this study were (i) to develop spatial and temporal patterns of pollutant concentration variation and (ii) to apportion the differences in exposure concentrations to background concentrations and those that are contributed from major highways. It was observed that: (a) particulate matter (PM2.5) in near-road communities is dominated by the regional background concentrations which account for more than 85% of the pollution; and (b) only near-road receptors are affected by the traffic-related air pollutant emissions from major highways while spatial and temporal variations of PM2.5 concentrations in near-road communities are less influenced by local traffic, subsiding rapidly to negligible concentrations at 300 m from the road. Modeled PM2.5 concentrations were compared with monitored data. For better air quality impact assessments, higher quality data such as time-specific traffic volume and fleet information as well as site-specific meteorological data could help yield more accurate concentration predictions. Modeled-to-monitored comparison shows that air quality in near-road communities is dominated by regional background concentrations.

Optimal Control Strategies for Air Quality Standards and Regulatory Policy

1972 ◽  
Vol 4 (2) ◽  
pp. 183-192 ◽  
Author(s):  
W L Gorr ◽  
S -Å Gustafson ◽  
K O Kortanek
Keyword(s):  
Air Quality ◽  
Control Strategies ◽  
Regulatory Policy ◽  
Quality Standards ◽  
Pollutant Emissions ◽  
Damage Functions ◽  
Air Quality Standards ◽  
Damage Costs ◽  
Accurate Picture ◽  
Grid Points

The setting of air quality standards for classes of air pollution in a region is one approach to the protection of public health and welfare by defining limits on levels of pollution in the air. We present methods to determine regional emission regulations that are (1) feasible in the sense that they lead to compliance with air quality standards and (2) optimal in the sense that the total economic impact due to implementation is minimized. Under goal (1) we set forth a procedure more sophisticated than heuristic procedures such as those guaranteeing compliance on a fixed rectangular set of grid receptor points in a region. We discuss various modifications responding to issues of regulatory policy, thereby obtaining a more accurate picture of the total impact of implementation of control strategies. We also indicate how damage functions may be incorporated, where now the standard (or the set of multiple standards) is a variable to be determined, together with emission rate reductions, so as to minimize the joint sum of individual control costs for the region and the total of damage costs, while keeping pollutant emissions below standards (to be determined) at all point coordinates in the region. In this way control strategies and emission standards may be derived jointly in a framework that automatically balances decrements of damage due to improved air quality with increased control costs associated with tighter standards. Furthermore the model determines the location of the maximum concentration intensities, which may not necessarily be on grid points, and hence indicates where to place sampling stations in order to guarantee compliance at all coordinates in the region over the prescribed period of time.

scholarly journals Roadside Air Quality Forecasting in Shanghai with a Novel Sequence-to-Sequence Model

2020 ◽  
Vol 17 (24) ◽  
pp. 9471
Author(s):  
Dongsheng Wang ◽  
Hong-Wei Wang ◽  
Chao Li ◽  
Kai-Fa Lu ◽  
Zhong-Ren Peng ◽  
...  
Keyword(s):  
Air Quality ◽  
Air Pollutants ◽  
Traffic Management ◽  
Fine Particulate Matter ◽  
Temporal Variations ◽  
Learning Ability ◽  
Observation Data ◽  
Deterministic Models ◽  
Co Concentrations ◽  
Air Quality Forecasting

The establishment of an effective roadside air quality forecasting model provides important information for proper traffic management to mitigate severe pollution, and for alerting resident’s outdoor plans to minimize exposure. Current deterministic models rely on numerical simulation and the tuning of parameters, and empirical models present powerful learning ability but have not fully considered the temporal periodicity of air pollutants. In order to take the periodicity of pollutants into empirical air quality forecasting models, this study evaluates the temporal variations of air pollutants and develops a novel sequence to sequence model with weekly periodicity to forecast air quality. Two-year observation data from Shanghai roadside air quality monitoring stations are employed to support analyzing and modeling. The results conclude that the fine particulate matter (PM2.5) and carbon monoxide (CO) concentrations show obvious daily and weekly variations, and the temporal patterns are nearly consistent with the periodicity of traffic flow in Shanghai. Compared with PM2.5, the CO concentrations are more affected by traffic variation. The proposed model outperforms the baseline model in terms of accuracy, and presents a higher linear consistency in PM2.5 prediction and lower errors in CO prediction. This study could assist environmental researchers to further improve the technologies for urban air quality forecasting, and serve as tools for supporting policymakers to implement related traffic management and emission control policies.

scholarly journals Analysis of SO2 Pollution Changes of Beijing-Tianjin-Hebei Region over China Based on OMI Observations from 2006 to 2017

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Zhifang Wang ◽  
Fengjie Zheng ◽  
Wenhao Zhang ◽  
Shutao Wang
Keyword(s):  
Air Quality ◽  
Control Strategies ◽  
Temporal Trends ◽  
Temporal Variations ◽  
Control Measures ◽  
Atmospheric Environment ◽  
Asia Pacific ◽  
Local Policy ◽  
The Government

Sulfur dioxide (SO2) in the planetary boundary layer (PBL) as a kind of gaseous pollutant has a strong effect regarding atmospheric environment, air quality, and climate change. As one of the most polluted regions in China, air quality in Beijing-Tianjin-Hebei (BTH) region has attracted more attention. This paper aims to study the characteristics of SO2 distribution and variation over BTH. Spatial and temporal variations for a long term (2006–2017) over BTH derived from OMI PBL SO2 products were discussed. The temporal trends confirm that the SO2 loading falls from average 0.88 DU to 0.16 DU in the past 12 years. Two ascending fluctuations in 2007 and 2011 appeared to be closely related to the economic stimulus of each five-year plan (FYP). The spatial analysis indicates an imbalanced spatial distribution pattern, with higher SO2 level in the southern BTH and lower in the northern. This is a result of both natural and human factors. Meanwhile, the SO2 concentration demonstrates a decreasing trend with 14.92%, 28.57%, and 27.43% compared with 2006, during the events of 2008 Olympic Games, 2014 Asia-Pacific Economic Cooperation (APEC) summit, and 2015 Military Parade, respectively. The improvement indicates that the direct effect is attributed to a series of long-term and short-term control measures, which have been implemented by the government. The findings of this study are desirable to assist local policy makers in the BTH for drawing up control strategies regarding the mitigation of environmental pollution in the future.

scholarly journals Aerosol transport pathways and source attribution in China during the COVID-19 outbreak

2021 ◽  
Author(s):  
Lili Ren ◽  
Yang Yang ◽  
Hailong Wang ◽  
Pinya Wang ◽  
Lei Chen ◽  
...  
Keyword(s):  
Air Quality ◽  
North China Plain ◽  
North China ◽  
Control Strategies ◽  
Eastern China ◽  
Lower Troposphere ◽  
Aerosol Transport ◽  
Anthropogenic Aerosol ◽  
Transport Pathways ◽  
Local Emissions

Abstract. Due to the coronavirus disease 2019 (COVID-19) pandemic, human activities and industrial productions were strictly restricted during January–March 2020 in China. Despite the fact that anthropogenic aerosol emissions largely decreased, haze events still occurred. Characterization of aerosol transport pathways and attribution of aerosol sources from specific regions are beneficial to the air quality and pandemic control strategies. This study establishes source-receptor relationships in various regions of China during the COVID-19 outbreak based on the Community Atmosphere Model version 5 with Explicit Aerosol Source Tagging (CAM5-EAST). Our analysis shows that PM2.5 burden over the North China Plain between January 30 and February 19 is largely contributed by local emissions (40–66 %). For other regions in China, PM2.5 burden is largely contributed from non-local sources. During the polluted days of COVID-19 outbreak, local emissions within North China Plain and Eastern China, respectively, contribute 66 % and 87 % to the increase in surface PM2.5 concentrations. This is associated with the anomalous mid-tropospheric high pressure at the location of climatological East Asia trough and the consequently weakened winds in the lower troposphere, leading to the local aerosol accumulation. The emissions outside China, especially from South and Southeast Asia, contribute over 50 % to the increase in PM2.5 concentration in Southwestern China through transboundary transport during the polluted day. As the reduction in emissions in the near future, aerosols from long-range transport together with unfavorable meteorological conditions are increasingly important to regional air quality and need to be taken into account in clean air plans.

scholarly journals Chemical characteristics of inorganic ammonium salts in PM<sub>2.5</sub> in the atmosphere of Beijing (China)

2011 ◽  
Vol 11 (6) ◽  
pp. 17127-17176 ◽  
Author(s):  
A. Ianniello ◽  
F. Spataro ◽  
G. Esposito ◽  
I. Allegrini ◽  
M. Hu ◽  
...  
Keyword(s):  
Fine Particulate Matter ◽  
Early Morning ◽  
Temporal Variations ◽  
Diurnal Variations ◽  
Local Source ◽  
Particle Interactions ◽  
Atmospheric Conditions ◽  
Fine Particulate ◽  
Annular Denuder ◽  
Beijing China

Abstract. The atmospheric concentrations of gaseous HNO3, HCl and NH3 and their relative salts have been measured during two field campaigns in the winter and in the summer of 2007 at Beijing (China), as part of CAREBEIJING (Campaigns of Air Quality Research in Beijing and Surrounding Region). In this study, annular denuder technique was used with integration times of 2 and 24 h to collect inorganic and soluble PM2.5 without interferences from gas-particle and particle-particle interactions. The results were discussed from the standpoint of temporal and diurnal variations and meteorological effects. Fine particulate Cl−, NH4+ and SO42− exhibited distinct temporal variations, while fine particulate NO3− did not show much variation with respect to season. Daily mean concentrations of fine particulate NH4+ and SO42− were higher during summer (12.30 μg m−3 and 18.24 μg m−3, respectively) than during winter (6.51 μg m−3 and 7.50 μg m−3, respectively). Instead, daily mean concentrations of fine particulate Cl− were higher during winter (2.94 μg m−3) than during summer (0.79 μg m−3), while fine particulate NO3− showed similar variations both in winter (8.38 μg m−3) and in summer (9.62 μg m−3) periods. However, the presence of large amounts of fine particulate NO3− even in summer are due to higher local and regional concentrations of NH3 in the atmosphere available to neutralize H2SO4 and HNO3, which is consistent with the observation that the measured particulate species were neutralized. Indeed, the composition of fine particulate matter indicated the domination of (NH4)2SO4 during winter and summer periods. In addition, the high relative humidity conditions in summer period seemed to dissolve a significant fraction of HNO3 and NH3 enhancing fine particulate NO3− and NH4+ in the atmosphere. All measured particulate species showed diurnal similar patterns during the winter and summer periods with higher peaks in the early morning, especially in summer, when humid and stable atmospheric conditions occurred. These diurnal variations were affected nearly by wind direction suggesting regional and local source influences. Indeed, the fine particulate species were also correlated with NOx and PM2.5, supporting the hypothesis that the traffic may be also an important source of secondary particles.

scholarly journals Differential Effects of the COVID-19 Lockdown and Regional Fire on the Air Quality of Medellín, Colombia

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1137
Author(s):  
Juan J. Henao ◽  
Angela M. Rendón ◽  
K. Santiago Hernández ◽  
Paola A. Giraldo-Ramirez ◽  
Vanessa Robledo ◽  
...  
Keyword(s):  
Air Quality ◽  
Fine Particulate Matter ◽  
Decision Makers ◽  
Regression Methods ◽  
Pollution Levels ◽  
Range Transport ◽  
Fire Activity ◽  
Local Emissions

Governments’ responses to the COVID-19 pandemic provide a unique opportunity to study the effects of restricted socioeconomic activity on air quality. Here, we study the changes in air pollution levels during the lockdown in Medellín and its metropolitan area, Colombia, for periods with and without enhanced regional fire activity, considering the effects of meteorology using random forest and multiple linear regression methods. The lockdown measures, which reduced mean traffic volume by 70% compared to 2016–2019, resulted in reductions for PM2.5 (50–63%), PM10 (59–64%), NO (75–76%), NO2 (43–47%), and CO (40–47%), while O3 concentration increased by 19–22%. In contrast, when fire activity was high, the effects of the lockdown on air quality were shadowed by the long-range transport of biomass burning emissions, increasing fine particulate matter and ozone. This study shows that healthier levels are achievable through significant efforts from decision-makers and society. The results highlight the need to develop integral measures that do not only consider reductions in the local emissions from transportation and industry, but also the role of fire activity in the region, as well as the difficulties of achieving reductions in ozone from measures that are effective at reducing primary pollutants.

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