scholarly journals Observational analyses of dramatic developments of a severe air pollution event in the Beijing area

2018 ◽  
Vol 18 (6) ◽  
pp. 3919-3935 ◽  
Author(s):  
Ju Li ◽  
Jielun Sun ◽  
Mingyu Zhou ◽  
Zhigang Cheng ◽  
Qingchun Li ◽  
...  
Keyword(s):  
Air Pollution ◽  
Turbulent Mixing ◽  
Rapid Development ◽  
Surface Wind ◽  
Aerosol Formation ◽  
Beijing Area ◽  
Pollution Event ◽  
Pollutant Transfer ◽  
Pm2.5 Concentration

Abstract. A rapid development of a severe air pollution event in Beijing, China, at the end of November 2015 was investigated with unprecedented observations collected during the field campaign of the Study of Urban Rainfall and Fog/Haze (SURF-15). Different from previous statistical analyses of air pollution events and their correlations with meteorological environmental conditions in the area, the role of turbulent mixing in the pollutant transfer was investigated in detail. The analyses indicate that the major pollution source associated with high particulate matter of diameter 2.5 µm (PM2.5) was from south of Beijing. Before the day of the dramatic PM2.5 increase, the nighttime downslope flow from the mountains to the west and north of Beijing reduced the surface PM2.5 concentration northwest of Beijing. The nighttime surface stable boundary layer (SBL) not only kept the relatively less-polluted air near the surface, it also shielded the rough surface from the pollutant transfer by southwesterly winds above the SBL, leading to the fast transport of pollutants over the Beijing area at night. As the daytime convective turbulent mixing developed in the morning, turbulent mixing transported the elevated polluted air downward even though the weak surface wind was from northeast, leading to the dramatic increase of the surface PM2.5 concentration in the urban area. As a result of both turbulent mixing and advection processes with possible aerosol growth from secondary aerosol formation under the low-wind and high-humidity conditions, the PM2.5 concentration reached over 700 µg m−3 in the Beijing area by the end of the day. Contributions of the two transporting processes to the PM2.5 oscillations prior to this dramatic event were also analyzed. The study demonstrates the important role of large-eddy convective turbulent mixing in vertical transfer of pollutants and the role of the SBL in not only decoupling vertical transport of trace gases and aerosols but also in accelerating horizontal transfer of pollutants above.

scholarly journals Observational Analyses of Dramatic Developments of A Severe Air Pollution Event in the Beijing Area

2017 ◽  
Author(s):  
Ju Li ◽  
Jielun Sun ◽  
Mingyu Zhou ◽  
Zhigang Cheng ◽  
Qingchun Li ◽  
...  
Keyword(s):  
Air Pollution ◽  
Turbulent Mixing ◽  
Rapid Development ◽  
Surface Wind ◽  
Pollution Source ◽  
Aerosol Formation ◽  
Beijing Area ◽  
Pollution Event ◽  
Beijing China ◽  
Pm2.5 Concentration

Abstract. A rapid development of a severe air pollution event at Beijing, China at the end of November 2015 was investigated with observations collected during the Study of Urban Rainfall and Fog/Haze (SURF-15). The analyses indicate that the major pollution source associated with particulate matter of diameter 2.5 μm (PM2.5) was from south of Beijing. On the night of 29 November, the surface stable boundary layer (SBL) was formed northwest of Beijing due to the northwesterly wind downslope of the mountains surrounding Beijing. This relatively cold and less polluted air also diluted the surface air northwest of Beijing while in the southeast of Beijing, the PM2.5 concentration increased continuously through the transport of the surface southwest flow. Around the midnight, the wind above the SBL switched from northerly to southwesterly and transported the heavy polluted air over Beijing. As the daytime convective turbulent mixing developed in the morning of 30 November, turbulent mixing transported the upper polluted air downward, leading to the dramatic increase of the PM2.5 concentration in the urban area. Meanwhile, the daytime weakly northeast-east surface wind led to the horizontal transport of the high PM2.5 air westwards towards Beijing, which further enhanced the PM2.5 increase at Beijing. As a result of both turbulent mixing and advection with possible aerosol growth from secondary aerosol formation under the low wind and high humidity conditions, the PM2.5 concentration reached over 700 μg m−3 at Beijing by the end of 30 November. Contributions of the two transporting processes to the PM2.5 oscillations prior to this dramatic event were also analyzed.

scholarly journals How Do Economic Growth, Urbanization, and Industrialization Affect Fine Particulate Matter Concentrations? An Assessment in Liaoning Province, China

2020 ◽  
Vol 17 (15) ◽  
pp. 5441
Author(s):  
Tuo Shi ◽  
Yuanman Hu ◽  
Miao Liu ◽  
Chunlin Li ◽  
Chuyi Zhang ◽  
...  
Keyword(s):  
Economic Growth ◽  
Air Pollution ◽  
Particulate Matter ◽  
Rapid Development ◽  
Fine Particulate Matter ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Liaoning Province ◽  
Fine Particulate ◽  
Pm2.5 Concentration

With China’s rapid development, urban air pollution problems occur frequently. As one of the principal components of haze, fine particulate matter (PM2.5) has potential negative health effects, causing widespread concern. However, the causal interactions and dynamic relationships between socioeconomic factors and ambient air pollution are still unclear, especially in specific regions. As an important industrial base in Northeast China, Liaoning Province is a representative mode of social and economic development. Panel data including PM2.5 concentration and three socio-economic indicators of Liaoning Province from 2000 to 2015 were built. The data were first-difference stationary and the variables were cointegrated. The Granger causality test was used as the main method to test the causality. In the results, in terms of the causal interactions, economic activities, industrialization and urbanization processes all showed positive long-term impacts on changes of PM2.5 concentration. Economic growth and industrialization also significantly affected the variations in PM2.5 concentration in the short term. In terms of the contributions, industrialization contributed the most to the variations of PM2.5 concentration in the sixteen years, followed by economic growth. Though Liaoning Province, an industry-oriented region, has shown characteristics of economic and industrial transformation, policy makers still need to explore more targeted policies to address the regional air pollution issue.

scholarly journals The Role of Meteorological Conditions and Pollution Control Strategies in Reducing Air Pollution in Beijing during APEC 2014 and Parade 2015

2017 ◽  
Author(s):  
Pengfei Liang ◽  
Tong Zhu ◽  
Yanhua Fang ◽  
Yingruo Li ◽  
Yiqun Han ◽  
...  
Keyword(s):  
Air Pollution ◽  
Pollution Control ◽  
Meteorological Parameters ◽  
Control Strategies ◽  
Meteorological Conditions ◽  
Air Pollutant ◽  
Pollutant Concentrations ◽  
Air Pollutant Concentrations ◽  
Pm2.5 Concentration

Abstract. To control severe air pollution in China, comprehensive pollution control strategies have been implemented throughout the country in recent years. To evaluate the effectiveness of these strategies, the influence of meteorological conditions on levels of air pollution needs to be determined. We therefore developed a generalized linear regression model (GLM) to establish the relationship between the concentrations of air pollutants and meteorological parameters. Using the intensive air pollution control strategies implemented during the Asia-Pacific Economic Cooperation Forum in 2014 (APEC 2014) and the Victory Parade for the Commemoration of the 70th Anniversary of the Chinese Anti-Japanese War and the World Anti-Fascist War in 2015 (Parade 2015) as examples, we estimated the role of meteorological conditions and pollution control strategies in reducing air pollution levels in Beijing. During the APEC (1 October to 31 December 2014) and Parade (1 August to 31 December 2015) sampling periods, atmospheric particulate matter of aerodynamic diameter ≤ 2.5 μm (PM2.5) samples were collected and gaseous pollutants (SO2, NO, NOx, and O3) were measured online at a site in Peking University (PKU). The concentrations of all pollutants except ozone decreased dramatically (by more than 20 %) during both events, compared with the levels during non-control periods. To determine the influence of meteorological conditions on the levels of air pollution, we first compared the air pollutant concentrations during days with stable meteorological conditions (i.e. when the daily average wind speed (WS) was less than 2.50 m s−1 and planetary boundary layer (PBL) height was lower than 290 m). We found that the average PM2.5 concentration during APEC decreased by 45.7 % compared with the period before APEC and by 44.4 % compared with the period after APEC. This difference was attributed to emission reduction efforts during APEC. However, there were few days with stable meteorological conditions during Parade. As such, we were unable to estimate the level of emission reduction efforts during this period. Finally, GLMs based only on meteorological parameters were built to predict air pollutant concentrations, which could explain more than 70 % of the variation in air pollutant concentration levels, after incorporating the nonlinear relationships between certain meteorological parameters and the concentrations of air pollutants. Evaluation of the GLM performance revealed that the GLM, even based only on meteorological parameters, could be satisfactory to estimate the contribution of meteorological conditions in reducing air pollution, and hence the contribution of control strategies in reducing air pollution. Using the GLM, we found that the meteorological conditions and pollution control strategies contributed 30 % and 28 % to the reduction of the PM2.5 concentration during APEC 2014, and 38 % and 25 % during Parade 2015. We also estimated the contribution of meteorological conditions and control strategies implemented during the two events in reducing the concentrations of gaseous pollutants and PM2.5 components with the GLMs, revealing the effective control of anthropogenic emissions.

scholarly journals Role of the boundary layer dynamics effects on an extreme air pollution event in Paris

2016 ◽  
Vol 141 ◽  
pp. 571-579 ◽  
Author(s):  
J.-C. Dupont ◽  
M. Haeffelin ◽  
J. Badosa ◽  
T. Elias ◽  
O. Favez ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Pollution Event ◽  
Boundary Layer Dynamics

PM2.5 Concentration Prediction for Air Pollution using Machine Learning Algorithms

2019 ◽  
Vol 28 (1) ◽  
pp. 349-354 ◽  
Author(s):  
Ahmed Samy Abd El Aziz Moursi ◽  
Marwa Shouman ◽  
Ezz El-din Hemdan ◽  
Nawal El-Fishawy
Keyword(s):  
Machine Learning ◽  
Air Pollution ◽  
Learning Algorithms ◽  
Machine Learning Algorithms ◽  
Concentration Prediction ◽  
Pm2.5 Concentration

scholarly journals Impacts of primary emissions and secondary aerosol formation on air pollution in an urban area of China during the COVID-19 lockdown

2021 ◽  
Vol 150 ◽  
pp. 106426
Author(s):  
Jie Tian ◽  
Qiyuan Wang ◽  
Yong Zhang ◽  
Mengyuan Yan ◽  
Huikun Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Urban Area ◽  
Aerosol Formation ◽  
Secondary Aerosol ◽  
Primary Emissions

scholarly journals X-change symposium: status and future of modern radiation oncology—from technology to biology

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Stefanie Corradini ◽  
Maximilian Niyazi ◽  
Dirk Verellen ◽  
Vincenzo Valentini ◽  
Seán Walsh ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Radiation Oncology ◽  
Trial Design ◽  
Rapid Development ◽  
Clinical Trial Design ◽  
Current Status ◽  
Treatment Modalities ◽  
Special Treatment ◽  
Image Guided Radiotherapy

AbstractFuture radiation oncology encompasses a broad spectrum of topics ranging from modern clinical trial design to treatment and imaging technology and biology. In more detail, the application of hybrid MRI devices in modern image-guided radiotherapy; the emerging field of radiomics; the role of molecular imaging using positron emission tomography and its integration into clinical routine; radiation biology with its future perspectives, the role of molecular signatures in prognostic modelling; as well as special treatment modalities such as brachytherapy or proton beam therapy are areas of rapid development. More clinically, radiation oncology will certainly find an important role in the management of oligometastasis. The treatment spectrum will also be widened by the rational integration of modern systemic targeted or immune therapies into multimodal treatment strategies. All these developments will require a concise rethinking of clinical trial design. This article reviews the current status and the potential developments in the field of radiation oncology as discussed by a panel of European and international experts sharing their vision during the “X-Change” symposium, held in July 2019 in Munich (Germany).

scholarly journals Pros and cons for the role of air pollution on COVID‐19 development

Allergy ◽  
2021 ◽  
Author(s):  
Isabella Annesi‐Maesano ◽  
Cara Nichole Maesano ◽  
Maria D’Amato ◽  
Gennaro D’Amato
Keyword(s):  
Air Pollution ◽  
Pros And Cons
Sign in / Sign up

Export Citation Format

Share Document