scholarly journals Ozone affected by a succession of four landfall typhoons in the Yangtze River Delta, China: major processes and health impacts

2020 ◽  
Author(s):  
Chenchao Zhan ◽  
Min Xie ◽  
Chongwu Huang ◽  
Tijian Wang ◽  
Jane Liu ◽  
...  
Keyword(s):  
Yangtze River ◽  
Mainland China ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Vertical Diffusion ◽  
The Yrd ◽  
The Impact ◽  
The Yangtze River Delta ◽  
Pollution Episodes

Abstract. Landfall typhoon can significantly affect O3 in the Yangtze River Delta (YRD) region. In this study, we investigate a unique case characterized by two multiday regional O3 pollution episodes related to four successive landfall typhoons in the summer of 2018 in the YRD. The results show that O3 pollution episodes mainly occurred during the period from the end of typhoon and the arrival of the next typhoon. The moment that typhoon reached the 24-h warning line and the last moment of typhoon activity in the mainland China can be roughly regarded as time nodes. Meanwhile, the variations of O3 was related to the track, duration and landing intensity of the typhoons. The impact of typhoon on O3 was like a wave superimposed on the background of high O3 concentration in the YRD in summer. When typhoon was near the 24-h warning line before it landed the coast line of the YRD, the prevailing wind originally from the ocean changed to from the inland, and transported lots of precursors from the polluted areas to the YRD. With typhoon, the low temperature, strong upward airflows, more precipitation and wild wind prevented high O3 episodes. After typhoon, the air below the 700 hPa atmospheric layer was warm and dry, which was conductive to the formation of O3 from the abundance of precursors. It is note-worthy that O3 is mainly generated in the middle of boundary layer (~ 1000 m), and then transported to the surface by downward airflows or turbulences. Moreover, O3 can be accumulated and trapped on the ground due to the poor diffusion conditions because the vertical diffusion and horizontal diffusion were suppressed by downward airflows and light wind, respectively. The premature mortalities attributed to O3 exposure in the YRD during the study period is 194.0, more than the casualties caused directly by the typhoons. This work enhances our understanding of how landfall typhoons affect O3 in the YRD, which can be helpful to forecast the O3 pollution synthetically impacted by the subtropical high and typhoon.

scholarly journals Ozone affected by a succession of four landfall typhoons in the Yangtze River Delta, China: major processes and health impacts

2020 ◽  
Vol 20 (22) ◽  
pp. 13781-13799
Author(s):  
Chenchao Zhan ◽  
Min Xie ◽  
Chongwu Huang ◽  
Jane Liu ◽  
Tijian Wang ◽  
...  
Keyword(s):  
Yangtze River ◽  
Yangtze River Delta ◽  
Photochemical Reactions ◽  
River Delta ◽  
The Yangtze River ◽  
High Concentration ◽  
The Yrd ◽  
The Impact ◽  
The Yangtze River Delta ◽  
Pollution Episodes

Abstract. Landfall typhoons can significantly affect O3 in the Yangtze River Delta (YRD) region. In this study, we investigate a unique case characterized by two multiday regional O3 pollution episodes related to four successive landfall typhoons in the summer of 2018 in the YRD. The results show that O3 pollution episodes mainly occurred during the period from the end of a typhoon to the arrival of the next typhoon. The time when a typhoon reached the 24 h warning line and the time when the typhoon dies away in mainland China can be roughly regarded as time nodes. Meanwhile, the variations of O3 were related to the track, duration and landing intensity of the typhoons. The impact of typhoons on O3 was like a wave superimposed on the background of high O3 concentration in the YRD in summer. When a typhoon was near the 24 h warning line before it landed on the coastline of the YRD, the prevailing wind originally from the ocean changed to be from inland, and it transported lots of precursors from the polluted areas to the YRD. Under influences of the typhoon, the low temperature, strong upward airflows, more precipitation and wild wind hindered occurrences of high O3 episodes. After the passing of the typhoon, the air below the 700 hPa atmospheric layer was warm and dry, and the downward airflows resumed. The low troposphere was filed with high concentration of O3 due to O3-rich air transported from the low stratosphere and strong photochemical reactions. It is noteworthy that O3 was mainly generated in the middle of the boundary layer (∼ 1000 m) instead of at the surface. High O3 levels remained in the residual layer at night, and would be transported to the surface by downward airflows or turbulence by the second day. Moreover, O3 can be accumulated and trapped on the ground due to the poor diffusion conditions because the vertical diffusion and horizontal diffusion were suppressed by downward airflows and light wind, respectively. The premature deaths attributed to O3 exposure in the YRD during the study period were 194.0, more than the casualties caused directly by the typhoons. This work has enhanced our understanding of how landfall typhoons affect O3 in the YRD and thus can be useful in forecasting O3 pollution in regions strongly influenced by typhoon activities.

scholarly journals Column and Surface Aerosol Optical Properties and Their Association with Meteorology in the Yangtze River Delta

2019 ◽  
Vol 8 (4) ◽  
pp. 8255-8259
Keyword(s):  
Optical Properties ◽  
Yangtze River ◽  
Negative Relationship ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Negative Effect ◽  
The Yrd ◽  
The Impact ◽  
The Yangtze River Delta

Aerosols played an important role in climate change during recent years in China. Many kinds of researches in different areas in China, particularly over the Yangtze River Delta (YRD) region in East China is measured during the period from January 2013 to December 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) derived aerosol optical depth (AOD), particulate matter concentrations (PM2.5) and surface black carbon (BCS) was used in this study. Nanjing, Hangzhou, Shanghai, and Ningbo have been selected in this research as they are the major cities of the YRD region that represents different environments. Variation of AOD550, Ångström exponent (AE470-660) and PM2.5 are mainly discussed, and meanwhile, the relationship that exists between them and with the meteorology is also discussed in this work. Apart from this, the impact of visibility and water vapor are also considered to examine the influence on optical properties. The data and analysis indicate that urban cities have a higher value of AOD than rural background cities. High AOD was noticed in summer than in other seasons. AOD usually has a negative relationship with AE, except in summer. Similarly, the PM2.5 has a negative relationship with AOD, whereas, BCS has a positive correlation with AOD. Further, it was observed that the rise in temperature resulted in high AOD concentration. The visibility has negative effect on AOD, whereas, AQI follows similar pattern as that of visibility.

scholarly journals Investigating Ecosystem Service Trade-Offs/Synergies and Their Influencing Factors in the Yangtze River Delta Region, China

Land ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 106
Author(s):  
Jie Zhao ◽  
Cheng Li
Keyword(s):  
Influencing Factors ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Trade Off ◽  
Trade Offs ◽  
The Yrd ◽  
The Impact ◽  
The Yangtze River Delta

A comprehensive understanding of the ecosystem services (ESs) trade-off/synergy relationships has become increasingly important for ecological management and sustainable development. This study employed the Yangtze River Delta (YRD) region in China as the study area and investigated the spatiotemporal changes in three ESs, namely, carbon storage (CS), water purification (WP), and habitat quality (HQ). A trade-off/synergy degree (TSD) indicator was developed that allowed for the quantification of the trade-off/synergy intensity, and the spatial pattern of the TSD between ESs in the YRD region to be analyzed. Furthermore, a geographically weighted regression (GWR) model was used to analyze the relationship between the influencing factors and trade-offs/synergies. The results revealed that CS, WP, and HQ decreased by 0.28%, 2.49%, and 3.38%, respectively, from 2005 to 2015. The TSD indicator showed that the trade-off/synergy relationships and their magnitudes were spatially heterogeneous throughout the YRD region. The coefficients of the natural and socioeconomic factors obtained from the GWR indicated that their impacts on the trade-offs/synergies vary spatiotemporally. The impact factors had both positive and negative effects on the trade-offs/synergies. The findings of this study could improve the understanding of the spatiotemporal dynamics of trade-offs/synergies and their spatially heterogeneous correlations with related factors.

scholarly journals The influence of spatiality on shipping emissions, air quality and potential human exposure in the Yangtze River Delta/Shanghai, China

2019 ◽  
Vol 19 (9) ◽  
pp. 6167-6183 ◽  
Author(s):  
Junlan Feng ◽  
Yan Zhang ◽  
Shanshan Li ◽  
Jingbo Mao ◽  
Allison P. Patton ◽  
...  
Keyword(s):  
Air Quality ◽  
Yangtze River ◽  
Human Exposure ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Inland Water ◽  
The Yrd ◽  
The Impact ◽  
The Yangtze River Delta

Abstract. The Yangtze River Delta (YRD) and the megacity of Shanghai are host to one of the busiest port clusters in the world; the region also suffers from high levels of air pollution. The goal of this study was to estimate the contributions of shipping to regional emissions, air quality, and population exposure and to characterize the importance of the geographic spatiality of shipping lanes and different types of ship-related sources for the baseline year of 2015, which was prior to the implementation of China's Domestic Emission Control Areas (DECAs) in 2016. The WRF-CMAQ model, which combines the Weather Research and Forecasting model (WRF) and the Community Multi-scale Air Quality (CMAQ) model, was used to simulate the influence of coastal and inland-water shipping, port emissions and ship-related cargo transport on air quality and on the population-weighted concentrations (which is a measure of human exposure). Our results showed that the impact of shipping on air quality in the YRD was primarily attributable to shipping emissions within 12 NM (nautical miles) of shore, but emissions coming from the coastal area between 24 and 96 NM still contributed substantially to ship-related PM2.5 concentrations in the YRD. The overall contribution of ships to the PM2.5 concentration in the YRD could reach 4.62 µg m−3 in summer when monsoon winds transport shipping emissions onshore. In Shanghai city, inland-water going ships were major contributors (40 %–80 %) to the shipping impact on urban air quality. Given the proximity of inland-water ships to the urban populations of Shanghai, the emissions of inland-water ships contributed more to population-weighted concentrations. These research results provide scientific evidence to inform policies for controlling future shipping emissions; in particular, in the YRD region, expanding the boundary of 12 NM from shore in China's current DECA policy to around 100 NM from shore would include most of shipping emissions affecting air pollutant exposure, and stricter fuel standards could be considered for the ships on inland rivers and other waterways close to residential regions.

scholarly journals Spatial Association of Urbanization in the Yangtze River Delta, China

2020 ◽  
Vol 17 (19) ◽  
pp. 7276
Author(s):  
Wei Zhao ◽  
Xuan Liu ◽  
Qingxin Deng ◽  
Dongyang Li ◽  
Jianing Xu ◽  
...  
Keyword(s):  
Spatial Correlation ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Driving Mechanism ◽  
The Yangtze River ◽  
Spatial Integration ◽  
The Yrd ◽  
The Impact ◽  
The Yangtze River Delta

China is urbanizing rapidly, but current research into the spatiotemporal characteristics of urbanization often ignores the spatial and evolutionary associations of cities. Using the theory of spatial polarization and diffusion, together with a systematic analysis method, this study examined the spatial development process of urbanization in the Yangtze River Delta (YRD) region of China during 1995–2015. Results showed clear patterns in the scale and hierarchy of regional urbanization. Shanghai ranked first as the regional growth pole, while Nanjing, Hangzhou, and Suzhou ranked second. The spatial linkage index of urbanization showed that 10 cities (including Shanghai, Suzhou, and Hangzhou) constituted the densest spatial linkage network. The diffused area often became spatially polarized before the polarization then weakened as a new diffusion stage developed. The study also revealed that the spatial correlation urbanization differences in the YRD generally decreased. The polarization index revealed increasing spatial integration and correlation of urbanization in the YRD. This study proved that each city had a different spatial role in relation to other cities during different stages of development. Investigation of the driving mechanism of regional urbanization indicated that industrial modernization and relocation within the region provided the main endogenous driving force for the formation of spatial polarization or diffusion. Our research provides important scientific support for regional development planning. Furthermore, our analysis of the impact of spatial correlation within cities or a region could provide an important reference in relation to the regional environment and public health.

scholarly journals Policies towards Migrants in the Yangtze River Delta Urban Region, China: Does Local Hukou Still Matter after the Hukou Reform?

2020 ◽  
Vol 12 (24) ◽  
pp. 10448
Author(s):  
Qian Zhang ◽  
Joris Hoekstra
Keyword(s):  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Urban Region ◽  
The Yangtze River ◽  
Access Policy ◽  
Hukou Reform ◽  
Access Policies ◽  
The Impact ◽  
The Yangtze River Delta

The 2014 hukou reform introduced by the Chinese central government was a turning point in China’s policies towards migration. Different from the previous hukou policies, which were largely exclusionary, the reformed policy encouraged migrants to permanently settle in their destination cities and make use of the public services available there. However, the actual results and consequences of this policy seem to vary between cities. This is due to the fact that Chinese municipal governments still have their own discretionary power when it comes to defining the criteria for accessing a local hukou. This raises the question of what the real impact of the hukou policy reform has been. This paper attempts to answer this question. It starts with a hukou access policy analysis of 20 different cities in the Yangtze River delta urban region. This analysis shows that the strictness of the local hukou access policy is related to city specific factors such as economic strength, share of migrant population, and population size. In the second part of the paper, we examine the impact of local hukou access policies on the intentions of migrants. Based on two logistic regression models, we find that the stricter the local hukou access policy is, the more willing migrants are to convert their current hukou into a local hukou. Furthermore, we observed that the settlement intention of migrants has a V-shaped rather than a linear relation with the strictness of local hukou access policies. Cities with relatively loose and cities with relatively strict hukou access policies are more desired as permanent settlement location than cities with moderately strict hukou access policies.

scholarly journals Integrating Sustainability Assessment into Decoupling Analysis: A Focus on the Yangtze River Delta Urban Agglomerations

2020 ◽  
Vol 12 (19) ◽  
pp. 7872
Author(s):  
Yijia Huang ◽  
Jiaqi Zhang ◽  
Jinqun Wu
Keyword(s):  
Environmental Sustainability ◽  
Yangtze River ◽  
Sustainability Assessment ◽  
Yangtze River Delta ◽  
River Delta ◽  
The Yangtze River ◽  
Urban Agglomerations ◽  
Decoupling Analysis ◽  
The Yrd ◽  
The Yangtze River Delta

Rapid urbanization has led to a growing number of environmental challenges in large parts of China, where the Yangtze River Delta (YRD) urban agglomerations serve as a typical example. To evaluate the relationship between environmental sustainability gaps and urbanization in 26 cities of the YRD, this study revisited the environmental sustainability assessment (ESA) by combining the metrics of environmental footprints and planetary boundaries at the city level, and then integrated the footprint-boundary ESA framework into decoupling analysis. The results demonstrated considerable spatiotemporal heterogeneity in the environmental sustainability of water use, land use, carbon emissions, nitrogen emissions, phosphorus emissions and PM2.5 emissions across the YRD cities during the study period 2007–2017. Decoupling analysis revealed a positive sign that more than half of the 26 cities had achieved the decoupling of each category of environmental sustainability gaps from urbanization since 2014, especially for nitrogen and phosphorus emissions. On the basis of ESA and decoupling analysis, all the cities were categorized into six patterns, for which the optimal pathways towards sustainable development were discussed in depth. Our study will assist policy makers in formulating more tangible and differentiated policies to achieve decoupling between environmental sustainability gaps and urbanization.

scholarly journals Integrated studies of a regional ozone pollution synthetically affected by subtropical high and typhoon system in the Yangtze River Delta region, China

2016 ◽  
Author(s):  
Lei Shu ◽  
Min Xie ◽  
Tijian Wang ◽  
Pulong Chen ◽  
Yong Han ◽  
...  
Keyword(s):  
Yangtze River ◽  
Western Pacific Subtropical High ◽  
Yangtze River Delta ◽  
River Delta ◽  
Western Pacific ◽  
Subtropical High ◽  
The Yangtze River ◽  
Observational Analysis ◽  
The Yrd ◽  
The Yangtze River Delta

Abstract. Severe high ozone (O3) episodes usually have close relations to synoptic systems. A regional continuous O3 pollution episode is detected over the Yangtze River Delta (YRD) region in China during August 7–12, 2013, in which the O3 concentrations in more than half of the cities exceeding the national air quality standard. The maximum hourly concentration of O3 reaches 167.1 ppb. By means of the observational analysis and the WRF/CMAQ numerical simulation, the characteristics and the essential impact factors of the typical regional O3 pollution is integratedly investigated. The observational analysis shows that the atmospheric subsidence dominated by Western Pacific subtropical high plays a crucial role in the formation of high-level O3. The favorable weather conditions, such as extremely high temperature, low relative humidity and weak wind speed, caused by the abnormal strong subtropical high are responsible for the trapping and the chemical production of O3 in the boundary layer. In addition, when the YRD cities at the front of Typhoon Utor, the periphery circulation of typhoon system can enhance the downward airflows and cause worse air pollution. But when the typhoon system weakens the subtropical high, the prevailing southeasterly surface wind leads to the mitigation of the O3 pollution. The Integrated Process Rate (IPR) analysis incorporated in CMAQ is applied to further illustrate the combined influence of subtropical high and typhoon system in this O3 episode. The results show that the vertical diffusion (VDIF) and the gas-phase chemistry (CHEM) are two major contributors to O3 formation. During the episode, the contributions of VDIF and CHEM to O3 maintain the high values over 10 ppb/h in Shanghai, Hangzhou, and Nanjing. On August 10–11, the cities close to the sea are apparently affected by the typhoon system, with the contribution of VDIF increasing to 28.45 ppb/h in Shanghai and 19.76 ppb/h in Hangzhou. When the YRD region is under the control of the typhoon system, the contribution values of all individual processes decrease to a low level in all cities. These results provide an insight for the O3 pollution synthetically impacted by the Western Pacific subtropical high and the tropical cyclone system.

Sign in / Sign up

Export Citation Format

Share Document