scholarly journals Elevated dust layers inhibit dissipation of heavy anthropogenic surface air pollution

2020 ◽  
Author(s):  
Zhuang Wang ◽  
Cheng Liu ◽  
Zhouqing Xie ◽  
Qihou Hu ◽  
Meinrat O. Andreae ◽  
...  
Keyword(s):  
Air Quality ◽  
North China ◽  
Spherical Particles ◽  
Trace Gas ◽  
Anthropogenic Aerosols ◽  
Haze Pollution ◽  
Multi Wavelength ◽  
Upper Level ◽  
Winter Time

Abstract. Persistent winter–time heavy haze incidents caused by anthropogenic aerosols have repeatedly shrouded North China in recent years, while natural dust from west and northwest of China also frequently affects air quality in this region. Through continuous observation by a multi–wavelength Raman lidar, here we found that aerosols in North China are typically characterized by a pronounced vertical stratification, where scattering non–spherical particles (dust or mixtures of dust and anthropogenic aerosols) dominated above the planetary boundary layer (PBL), and absorbing spherical particles (anthropogenic aerosols) prevailed within the PBL. This stratification is governed by meteorological conditions that strong northwesterly winds usually prevailed in the lower free troposphere, and southerly winds are dominated in the PBL, producing persistent and intense haze pollution. With the accumulation of elevated dust, the proportion of aerosol and trace gas at the surface in the whole column increased. Model results show that, besides directly deteriorating air quality, the key role of the elevated dust is to depress the development of PBL and weaken the turbulence exchange, mostly by lower–level cooling and upper–level heating, and it is more obvious during dissipation stage, thus inhibiting the dissipation of heavy surface anthropogenic aerosols. The interactions of natural dust and anthropogenic aerosols under the unique topography of North China increases the surface anthropogenic aerosols and precursor gases, which may be one of the reasons why haze pollution in North China is heavier than that in other heavily polluted areas in China.

scholarly journals Elevated dust layers inhibit dissipation of heavy anthropogenic surface air pollution

2020 ◽  
Vol 20 (23) ◽  
pp. 14917-14932
Author(s):  
Zhuang Wang ◽  
Cheng Liu ◽  
Zhouqing Xie ◽  
Qihou Hu ◽  
Meinrat O. Andreae ◽  
...  
Keyword(s):  
Air Quality ◽  
North China ◽  
Spherical Particles ◽  
Trace Gas ◽  
Nonspherical Particles ◽  
Anthropogenic Aerosols ◽  
Haze Pollution ◽  
Multi Wavelength ◽  
Upper Level

Abstract. Persistent wintertime heavy haze incidents caused by anthropogenic aerosols have repeatedly shrouded North China in recent years, while natural dust from the west and northwest of China also frequently affects air quality in this region. Through continuous observation by a multi-wavelength Raman lidar, here we found that wintertime aerosols in North China are typically characterized by a pronounced vertical stratification, where scattering nonspherical particles (dust or mixtures of dust and anthropogenic aerosols) dominated above the planetary boundary layer (PBL), and absorbing spherical particles (anthropogenic aerosols) prevailed within the PBL. This stratification is governed by meteorological conditions that strong northwesterly winds usually prevailed in the lower free troposphere, and southerly winds dominated in the PBL, producing persistent and intense haze pollution. With the increased contribution of elevated dust to the upper aerosols, the proportion of aerosol and trace gas at the surface in the whole column increased. Model results show that, besides directly deteriorating air quality, the key role of the elevated dust is to depress the development of PBL and weaken the turbulent exchange, mostly by lower level cooling and upper level heating, and it is more obvious during the dissipation stage, thus inhibiting the dissipation of heavy surface anthropogenic aerosols. The interactions of natural dust and anthropogenic aerosols under the unique topography of North China increase the surface anthropogenic aerosols and precursor gases, which may be one of the reasons why haze pollution in North China is heavier than that in other heavily polluted areas in China.

scholarly journals Role of Large-Scale Circulation and Terrain in Causing Extreme Heat in Western North China

2016 ◽  
Vol 29 (7) ◽  
pp. 2511-2527 ◽  
Author(s):  
Ruidan Chen ◽  
Riyu Lu
Keyword(s):  
Large Scale ◽  
North China ◽  
Surface Air Temperature ◽  
Extreme Heat ◽  
Large Scale Circulation ◽  
Air Temperatures ◽  
Higher Temperature ◽  
Upper Level ◽  
Topographic Relief

Abstract Previous studies have suggested that, because of its particular location on the southeastern lee side of mountains, extreme heat (EH) over western north China (WNC) is affected by the foehn phenomenon. In this study, the EH days during summer over this region are categorized into foehn-favorable EH and no-foehn EH, according to whether there are anomalous northwesterlies over mountains, and composite analyses are performed on them. The analyzed results indicate that the no-foehn EH is characterized by an anticyclonic anomaly and a large-scale higher surface air temperature, while the foehn-favorable EH is featured by a cyclonic anomaly to the northeast and a localized higher temperature. Associated with the cyclonic anomaly, northwesterlies prevail over the mountain surface and provide a favorable environment for the occurrence of the foehn effect over WNC, which is located on the southeastern lee side of mountains. That is, both cyclonic and anticyclonic anomalies can induce EH over WNC (i.e., foehn-favorable EH and no-foehn EH, respectively). Further investigation indicates that large-scale cyclonic and anticyclonic anomalies tend to favor local descent and ascent anomalies over the lee side, respectively, through interaction with the particular terrain. Therefore, large-scale circulations and local terrain-induced winds play an offsetting role in affecting the surface air temperatures over WNC, and EH occurs when anomalous large-scale anticyclone or terrain-induced descent dominate. This study implies that attention should be paid to not only the upper-level/large-scale circulations but also to their impact on lower-level/local winds for temperature variability over the places with great topographic relief worldwide.

scholarly journals Air Quality And Health Benefits of Increasing Carbon Mitigation Tech-Innovation In China

2021 ◽  
Author(s):  
Shunlin Jin ◽  
Weidong Wang ◽  
Dragana Ostic ◽  
Caijing Zhang ◽  
Na Lu ◽  
...  
Keyword(s):  
Air Quality ◽  
Industrial Structure ◽  
Health Benefits ◽  
Low Carbon ◽  
Carbon Mitigation ◽  
Short Term ◽  
Stirpat Model ◽  
Haze Pollution ◽  
Patent Applications

Abstract Most studies on the short-term local benefits of carbon mitigation technologies on air quality improvement and health focus on specific technologies such as biofuels or Carbon sequestration technologies, while ignoring the overall role of the growing scale of low-carbon technologies, and the relevant empirical studies are particularly lacking. Based on STIRPAT model and EKC hypothesis, this paper takes 30 provinces of China from 2004 to 2016 as research samples, measures the carbon mitigation tech-innovation(CMTI) with Y02 low carbon patent applications, and constructs a econometric model to empirically analyze the effect of carbon mitigation tech-innovation in response to climate change on the inhibition of haze pollution. It draws on relevant studies to quantify air quality and health benefits of carbon mitigation tech-innovation. Research shows that a 1% increase in the number of low-carbon patent applications can reduce haze pollution by 0.066%. According to this estimate, to 2029,China's carbon mitigation tech-innovation could reduce PM2.5 concentration to 15µg/m3 preventing 5.597million premature deaths. The research further found that carbon mitigation tech-innovation can also indirectly inhibit haze pollution by triggering more systematic economic structure changes such as energy and industrial structure. Additionally, the study found that the role of grey tech-innovation(GT) related to improving the efficiency of fossil energy is stronger than that of clean technology(CT) related to the use of renewable energy. This suggests that for a large economy such as China, where coal is still the dominant source of energy consumption, the short-term local benefits of improving air quality and health through the use of grey tech-innovation to improve energy and industrial structure are still important to balance the cost of carbon mitigation.

scholarly journals An unexpected large continental source of reactive bromine and chlorine with significant impact on wintertime air quality

2020 ◽  
Author(s):  
Xiang Peng ◽  
Weihao Wang ◽  
Men Xia ◽  
Hui Chen ◽  
A R Ravishankara ◽  
...  
Keyword(s):  
Air Quality ◽  
Atmospheric Chemistry ◽  
North China ◽  
Primary Source ◽  
Ozone Production ◽  
Bromine Chloride ◽  
Halogen Atoms ◽  
Continental Source ◽  
Cl Atoms

Abstract Halogen atoms affect the budget of ozone and the fate of pollutants such as hydrocarbons and mercury. Yet their sources and significances in polluted continental regions are poorly understood. Here we report the observation of unprecedented levels (averaging to 60 parts per trillion) of bromine chloride (BrCl) at a mid-latitude site in North China during winter. Widespread coal burning in rural households and a photo-assisted process were the primary source of BrCl and other bromine gases. BrCl contributed about 55% of both bromine (Br) and chlorine (Cl) atoms. The halogen atoms increased the abundance of ‘conventional’ tropospheric oxidants (OH, HO2, and RO2) by 26–73%, and enhanced oxidation of hydrocarbon by nearly a factor of two and the net ozone production by 55%. Our study reveals the significant role of reactive halogen in winter atmospheric chemistry and the deterioration of air quality in continental regions where uncontrolled coal combustion is prevalent.

scholarly journals INVESTIGATING ALOFT AEROSOLS OVER CENTRAL-EASTERN CHINA USING CALIPSO MEASUREMENTS

2018 ◽  
Vol XLII-3/W5 ◽  
pp. 83-88
Author(s):  
J. Zou ◽  
K. Qin ◽  
J. Xu ◽  
X. Han
Keyword(s):  
North China ◽  
Rapid Development ◽  
Eastern China ◽  
Yangtze River Delta ◽  
Anthropogenic Source ◽  
Anthropogenic Aerosols ◽  
The North ◽  
Haze Pollution ◽  
Central Eastern ◽  
The Yrd

<p><strong>Abstract.</strong> The rapid development of China in the last decade has brought about serious environmental problems, among which the air quality has attracted much attention. Especially in the winter, haze events with PM<sub>2.5</sub> as the primary pollutant frequently occur, which has a huge strike on people's health. Such cumulative anthropogenic aerosols at surface over haze pollution regions could be lifted upwards by vertical turbulent mixing forming elevated haze layers that subsequent transport to distant regions. This paper attempts to analyze layer top altitude, ratio of anthropogenic source and optical properties by counting events occurring in aloft aerosols layer. CALIPSO satellite instruments are used for statistical analysis by screening layer data over central-eastern China from 2007 to 2016. In the most economically active and polluted areas of China, the North China Plain (NCP) and the Yangtze River Delta (YRD) are compared to analyze trend variations over ten years. Results shows that the frequency of occurrence of aloft layer in South China are higher than in North China, indicating that heat has a strong lifting effect on the planetary boundary layer (PBL). Further, the NCP has a unique high frequency value at 2.5<span class="thinspace"></span>km, while the YRD has two peaks, 3.5<span class="thinspace"></span>km and 2 km respectively. Moreover, in the past five years in the NCP (2011&amp;ndash;2016) and YRD (2012&amp;ndash;2016) regions, the anthropogenic source of pollutants dominated by smoke showed a downward trend year by year. In addition, monthly proportion of smoke and polluted dust are analyzed in NCP and YRD winter. Finally, the volume depolarization ratio is almost distributed within 0.2, indicating that the shape of the particles is irregular. The particulate color ratio has a sharp peak near 0.4&amp;ndash;0.7 suggesting that smaller particles dominate the size distribution during the winter months.</p>

Observations for the Role of Flux rope Eruption in a Geoeffective Solar Flare

2014 ◽  
Vol 4 (2) ◽  
pp. 555-564
Author(s):  
A.M Aslam
Keyword(s):  
Solar Flare ◽  
Flux Rope ◽  
Magnetic Configuration ◽  
Solar Dynamics Observatory ◽  
Multi Wavelength ◽  
Solar Dynamics ◽  
Halo Coronal Mass Ejection ◽  
Mass Ejection ◽  
The Waves

On September 24, 2011 a solar flare of M 7.1 class was released from the Sun. The flare was observed by most of the space and ground based observatories in various wavebands. We have carried out a study of this flare to understand its causes on Sun and impact on earth. The flare was released from NOAA active region AR 11302 at 12:33 UT. Although the region had already produced many M class flares and one X- class flare before this flare, the magnetic configuration was not relaxed and still continued to evolve as seen from HMI observations. From the Solar Dynamics Observatory (SDO) multi-wavelength (131 Ã…, 171 Ã…, 304 Ã… and 1600Ã…) observations we identified that a rapidly rising flux rope triggered the flare although HMI observations revealed that magnetic configuration did not undergo a much pronounced change. The flare was associated with a halo Coronal Mass Ejection (CME) as recorded by LASCO/SOHO Observations. The flare associated CME was effective in causing an intense geomagnetic storm with minimum Dst index -103 nT. A radio burst of type II was also recorded by the WAVES/WIND. In the present study attempt is made to study the nature of coupling between solar transients and geospace.

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

scholarly journals From Black to Blue Skies: Civil Society Perceptions of Air Pollution in Shanghai

2021 ◽  
pp. 1-22
Author(s):  
Amanda K. Winter ◽  
Huong Le ◽  
Simon Roberts
Keyword(s):  
Air Pollution ◽  
Civil Society ◽  
Air Quality ◽  
Qualitative Case Study ◽  
Field Research ◽  
Ecological Civilization ◽  
Civil Society Participation ◽  
Quality Indexes

Abstract This paper explores the perception and politics of air pollution in Shanghai. We present a qualitative case study based on a literature review of relevant policies and research on civil society and air pollution, in dialogue with air quality indexes and field research data. We engage with the concept of China's authoritarian environmentalism and the political context of ecological civilization. We find that discussions about air pollution are often placed in a frame that is both locally temporal (environment) and internationally developmentalist (economy). We raise questions from an example of three applications with different presentations of air quality index measures for the same time and place. This example and frame highlight the central role and connection between technology, data and evidence, and pollution visibility in the case of the perception of air pollution. Our findings then point to two gaps in authoritarian environmentalism research, revealing a need to better understand (1) the role of technology within this governance context, and (2) the tensions created from this non-participatory approach with ecological civilization, which calls for civil society participation.

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