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Extreme precipitation events are likely occur more frequently and lead to casualties and socio-economic losses as global warming intensifies. Therefore, exploring the characteristics of extreme precipitation events is essential. Based on meteorological station data from the middle and lower reaches of the Yangtze River Basin (MLYRB) from 1970 to 2018, we analyzed the spatiotemporal distributions of 11 extreme precipitation indices and considered the correlation between altitude and large-scale atmospheric circulation with extreme precipitation. To this end, we employed Sen's trend analysis, rescaled range analysis, the Mann-Kendall test, and continuous wavelet transform. The results indicate that on this spatial scale, extreme precipitation indices in the northwestern region of the MLYRB have mainly decreased, but they have increased along the eastern coastal region. From the perspective of the entire region, Hurst values of extreme precipitation indices are >0.5. Areas with consistent increases are mainly concentrated in the central region, while those with consistent decreases are mainly scattered in the northern and southern regions. Abrupt change in extreme precipitation indices mostly occurred in the 1980s and 1990s. The periodic oscillations of most indices tend toward high time-frequency scales (2.3 years or less). Consecutive wet days increased with increasing altitude; other indices changed similarly with increasing altitude, first increasing then decreasing before increasing again. Additionally, we found significant resonance periods between the extreme precipitation indices and the atmospheric circulation index, however, there were obvious differences in time domains.
Shuqi Wu; Zhuowei Hu; Zhiheng Wang; Shisong Cao; Yang Yang; Xinyuan Qu; Wenji Zhao. Spatiotemporal variations in extreme precipitation on the middle and lower reaches of the Yangtze River Basin (1970–2018). Quaternary International 2021, 592, 80 -96.
AMA StyleShuqi Wu, Zhuowei Hu, Zhiheng Wang, Shisong Cao, Yang Yang, Xinyuan Qu, Wenji Zhao. Spatiotemporal variations in extreme precipitation on the middle and lower reaches of the Yangtze River Basin (1970–2018). Quaternary International. 2021; 592 ():80-96.
Chicago/Turabian StyleShuqi Wu; Zhuowei Hu; Zhiheng Wang; Shisong Cao; Yang Yang; Xinyuan Qu; Wenji Zhao. 2021. "Spatiotemporal variations in extreme precipitation on the middle and lower reaches of the Yangtze River Basin (1970–2018)." Quaternary International 592, no. : 80-96.
Emergency response mechanisms were activated throughout China during the COVID-19 outbreak. It is different from the temporary, partial, and limited pollution control measures taken to ensure the regional environmental quality during several important events such as the 2008 Beijing Olympic Games and the 2014 Asia-Pacific Economic Cooperation (APEC). During the COVID-19 epidemic period, extensive movement of people and almost all unnecessary industrial production (necessary industrial production refers to the production of food, epidemic prevention materials, etc.) have been severely restricted, so transportation and industrial production have been greatly reduced. This is a rare extreme emission reduction scenario that presents a unique opportunity for atmospheric research. In this study, based on hourly mass concentration data of NO2 and SO2 from atmospheric monitoring sites in the Beijing-Tianjin-Hebei (BTH) region during the COVID-19 epidemic period, the changes in transportation and industrial production in the region, data statistics, and spatial analysis were used to analyze the pollution changes and their causes. The results indicate that the NO2 and SO2 concentrations in the BTH region decreased significantly during the epidemic period. The spatial distribution pattern of NO2 pollution in the BTH region was “high in the southeast and low in the northwest,” and SO2 pollution in the BTH region was high in the southern and eastern parts of Hebei. The initiation of emergency response level 1 had an obvious effect on reducing NO2 and SO2 pollution in the region, while the impact of emergency response level 2 and below was limited. Compared with the single traffic control, the comprehensive control, similar to the emergency response, had a better effect on reducing NO2 pollution in the region. The control of major large cities in the region also had a certain effect on alleviating NO2 and SO2 pollution in the entire region. Moreover, for activities under short-term control, it is particularly important to guard against the “retaliatory growth” after the control is lifted. By reducing and controlling some polluting industries in industrial production, the degree of NO2 and SO2 pollution in the region can be effectively reduced. The manufacturing industry of chemical raw materials and the chemical products and non-metallic mineral products industry made a great contribution to the change in industrial source pollution emissions in the BTH region during the COVID-19 epidemic. Road traffic emissions remained an important source of NO2 emissions in the BTH region during this period. NO2 emission reduction can be effectively achieved by controlling road traffic and transportation.
Nanchi Shen; Xue Zhao; Lingjun Li; Bingfeng Zhou; Fuzhou Duan; Wenji Zhao. Spatial and temporal variation characteristics of atmospheric NO2 and SO2 in the Beijing-Tianjin-Hebei region before and after the COVID-19 outbreak. Air Quality, Atmosphere & Health 2021, 14, 1175 -1188.
AMA StyleNanchi Shen, Xue Zhao, Lingjun Li, Bingfeng Zhou, Fuzhou Duan, Wenji Zhao. Spatial and temporal variation characteristics of atmospheric NO2 and SO2 in the Beijing-Tianjin-Hebei region before and after the COVID-19 outbreak. Air Quality, Atmosphere & Health. 2021; 14 (8):1175-1188.
Chicago/Turabian StyleNanchi Shen; Xue Zhao; Lingjun Li; Bingfeng Zhou; Fuzhou Duan; Wenji Zhao. 2021. "Spatial and temporal variation characteristics of atmospheric NO2 and SO2 in the Beijing-Tianjin-Hebei region before and after the COVID-19 outbreak." Air Quality, Atmosphere & Health 14, no. 8: 1175-1188.
The efforts in controlling PM2.5 have made achievements in China, whereas O3 increased when PM2.5 reduced. We used Pearson correlation analysis, self-organizing map, and least squares method to analyze the spatiotemporal characteristics of PM2.5, SO2, CO, NO2, and O3 in Beijing from 2014 to 2019 under the atmospheric control measures. The influence of land surface temperature (LST) on pollution was also explored. PM2.5 was strongly correlated with CO and NO2 and moderately correlated with SO2. The four pollutants were negatively correlated with O3. The correlation strengthened in winter and changed significantly in summer. Notably, PM2.5 showed the most obvious decline and also exhibited seasonal variability, with higher levels in autumn and winter. Spatially, PM2.5 was higher in the south and lower in the north. PM2.5 levels were higher in urban zones. For gaseous pollutants, CO, SO2, and NO2 levels decreased with a small decrease in NO2, and their spatiotemporal characteristics showed consistency with PM2.5, whereas O3 showed the opposite trend. CO and SO2 in all districts declined, but NO2 and O3 increased in some areas. O3 pollution was higher in the ecological conservation development zone than in urban zones. Finally, only O3 was significantly correlated with LST in 2019.
Shuang Liu; Atul Gautam; Xingchuan Yang; Jing Tao; Xinyu Wang; Wenji Zhao. Analysis of improvement effect of PM2.5 and gaseous pollutants in Beijing based on self-organizing map network. Sustainable Cities and Society 2021, 70, 102827 .
AMA StyleShuang Liu, Atul Gautam, Xingchuan Yang, Jing Tao, Xinyu Wang, Wenji Zhao. Analysis of improvement effect of PM2.5 and gaseous pollutants in Beijing based on self-organizing map network. Sustainable Cities and Society. 2021; 70 ():102827.
Chicago/Turabian StyleShuang Liu; Atul Gautam; Xingchuan Yang; Jing Tao; Xinyu Wang; Wenji Zhao. 2021. "Analysis of improvement effect of PM2.5 and gaseous pollutants in Beijing based on self-organizing map network." Sustainable Cities and Society 70, no. : 102827.
The Beijing-Tianjin-Hebei (BTH) region is the largest industrial cluster in northern China and its most prominent air pollution zone. Industrial emissions of PM2.5, SO2, NOx and other pollutants have a significant impact on regional air quality. Monitoring industrial pollution emissions is of great significance for the prevention and control of air pollution. The VIIRS Nightfire products can detect thermal anomalies in heavy industrial sectors, thus providing a new means for monitoring industrial activities. In this study, the VIIRS 375 product was selected to study the spatial and temporal changes of the heavy industrial thermal anomalies through spatial analysis and mathematical statistics methods. Furthermore, it is the first time to use thermal anomaly radiative power (CTRP) to evaluate the spatiotemporal pattern of industrial pollution emissions and its impact on air quality in the BTH region. We observed that the spatial distribution of CTRP was unbalanced and that Tangshan-Tianjin and Handan-Xingtai- Shijiazhuang were found to be high-density pollution areas. The CTRP in Tangshan and Handan were higher than in other cities, accounting for 72.41% of their area. From 2012 to 2018, CTRP in this region decreased by 17.2% per year while in Langfang decreased by 72.9% per year. The CTRP also showed a significantly positive correlation with industrial energy consumption. Emissions of SO2, NO2, and PM2.5 were high in the area of intense distribution of thermal anomalies. When compared to the density of tropospheric NO2 and SO2 columns and the monitored concentrations of SO2 and PM2.5, CTRP was consistent with the trend of interannual variations and spatial distributions. The energy-saving and emissions reduction measures taken by the industrial sector in the BTH contributed significantly to improving regional air quality. Remote sensing-based monitoring can provide regional industrial energy consumption in real-time and reflect pollution emissions, providing a basis for industrial pollution emissions regulation and reduction policy.
Shuang Sun; Lingjun Li; Zhihong Wu; Atul Gautam; Jinxiang Li; Wenji Zhao. Variation of industrial air pollution emissions based on VIIRS thermal anomaly data. Atmospheric Research 2020, 244, 105021 .
AMA StyleShuang Sun, Lingjun Li, Zhihong Wu, Atul Gautam, Jinxiang Li, Wenji Zhao. Variation of industrial air pollution emissions based on VIIRS thermal anomaly data. Atmospheric Research. 2020; 244 ():105021.
Chicago/Turabian StyleShuang Sun; Lingjun Li; Zhihong Wu; Atul Gautam; Jinxiang Li; Wenji Zhao. 2020. "Variation of industrial air pollution emissions based on VIIRS thermal anomaly data." Atmospheric Research 244, no. : 105021.
Agricultural floods in the middle and lower reaches of the Yangtze River, known as the “land of fish and rice” in China, have increased both in areal coverage and frequency over the past 50 years, presenting a grave challenge to sustainable development and food security in the region. Studying the spatiotemporal variation characteristics of agricultural floods in this region is thus important for providing a scientific basis for regional flood control and disaster mitigation. We used variation trend analyses, Mann–Kendall tests, wavelet analyses, and center of gravity modeling to study spatiotemporal changes in agricultural floods in the study area, based on agricultural flood indicators. Changes in agricultural flood frequency showed an overall increasing trend. The frequency of floods changed abruptly in 1990, with the average frequency of floods per station increasing by 0.2086/year from 1991 through 2018, characterized by multiple time-scale changes. The time scale of 17 years had three low–high cycles, that of eight years had six, and that of four years had 13. Agricultural floods in the study area were concentrated in the southern Yangtze River and mainly occurred in northeastern Jiangxi Province and the southeastern Zhejiang Province. The area with high agricultural flood indices increased. Agricultural floods were closely related to the Yangtze River and the direction of the gravity center of agricultural floods was similar to that of the river. Affected by precipitation intensity and frequency, the gravity center fluctuated greatly and generally alternated from southwest to northeast.
Shuqi Wu; Shisong Cao; Zhiheng Wang; Xinyuan Qu; Shanfei Li; Wenji Zhao. Spatiotemporal Variations In Agricultural Flooding In Middle and Lower Reaches of Yangtze River From 1970 to 2018. Sustainability 2019, 11, 6613 .
AMA StyleShuqi Wu, Shisong Cao, Zhiheng Wang, Xinyuan Qu, Shanfei Li, Wenji Zhao. Spatiotemporal Variations In Agricultural Flooding In Middle and Lower Reaches of Yangtze River From 1970 to 2018. Sustainability. 2019; 11 (23):6613.
Chicago/Turabian StyleShuqi Wu; Shisong Cao; Zhiheng Wang; Xinyuan Qu; Shanfei Li; Wenji Zhao. 2019. "Spatiotemporal Variations In Agricultural Flooding In Middle and Lower Reaches of Yangtze River From 1970 to 2018." Sustainability 11, no. 23: 6613.
Air pollution, including particulate matter (PM2.5) pollution, is extremely harmful to the environment as well as human health. The Beijing–Tianjin–Hebei (BTH) Region has experienced heavy PM2.5 pollution within China. In this study, a six-year time series (January 2013–December 2018) of PM2.5 mass concentration data from 102 air quality monitoring stations were studied to understand the spatio-temporal variation characteristics of the BTH region. The average annual PM2.5 mass concentration in the BTH region decreased from 98.9 μg/m3 in 2013 to 64.9 μg/m3 in 2017. Therefore, China has achieved its Air Pollution Prevention and Control Plan goal of reducing the concentration of fine particulate matter in the BTH region by 25% by 2017. The PM2.5 pollution in BTH plain areas showed a more significant change than mountains areas, with the highest PM2.5 mass concentration in winter and the lowest in summer. The results of spatial autocorrelation and cluster analyses showed that the PM2.5 mass concentration in the BTH region from 2013–2018 showed a significant spatial agglomeration, and that spatial distribution characteristics were high in the south and low in the north. Changes in PM2.5 mass concentration in the BTH region were affected by both socio-economic factors and meteorological factors. Our results can provide a point of reference for making PM2.5 pollution control decisions.
Lili Wang; Qiulin Xiong; Gaofeng Wu; Atul Gautam; Jianfang Jiang; Shuang Liu; Wenji Zhao; Hongliang Guan. Spatio-Temporal Variation Characteristics of PM2.5 in the Beijing–Tianjin–Hebei Region, China, from 2013 to 2018. International Journal of Environmental Research and Public Health 2019, 16, 4276 .
AMA StyleLili Wang, Qiulin Xiong, Gaofeng Wu, Atul Gautam, Jianfang Jiang, Shuang Liu, Wenji Zhao, Hongliang Guan. Spatio-Temporal Variation Characteristics of PM2.5 in the Beijing–Tianjin–Hebei Region, China, from 2013 to 2018. International Journal of Environmental Research and Public Health. 2019; 16 (21):4276.
Chicago/Turabian StyleLili Wang; Qiulin Xiong; Gaofeng Wu; Atul Gautam; Jianfang Jiang; Shuang Liu; Wenji Zhao; Hongliang Guan. 2019. "Spatio-Temporal Variation Characteristics of PM2.5 in the Beijing–Tianjin–Hebei Region, China, from 2013 to 2018." International Journal of Environmental Research and Public Health 16, no. 21: 4276.
In order to assess the pollution levels and health risks of PM2.5-bound metals in Baoding City before and after the heating period, samples were collected in 2016 at Hebei University from September 25th to November 14th during the non-heating period, and November 15th to December 26th during the heating period, respectively. ICP-MS was applied to analyze seven heavy metals (Cr, Zn, Cu, Pb, Ni, Cd and Fe). The statistical analysis, enrichment factor (EF), pollution load index method, and Risk Assessment Method proposed by U.S. EPA were used to evaluate the non-carcinogenic risks of six of these heavy metals (Cr, Zn, Cu, Pb, Ni and Cd) and carcinogenic risks of three of these heavy metals (Cr, Ni and Cd). The results showed three main results. First, the average daily PM2.5 concentrations of the national air monitoring stations was 155.66 μg·m−3 which was 2.08 times as high as that of the second level criterion in China (75 μg·m−3) during the observation period. Compared with the non-heating period, all heavy metals concentrations increased during heating period. The growth rates of Pb and Ni were the highest and the lowest, which were 88.03 and 5.11 percent, respectively. Second, the results of enrichment factor indicated that the EF values of all heavy metals were higher during the heating period in comparison with during the non-heating period, but the degree of enrichment of all heavy metals remained unchanged. Not only those, Cr and Ni were minimally enriched and were affected by both human and natural factors, Pb, Cu and Zn were significantly enriched and were mainly affected by human factors, the enrichment of Cd was much higher than that of the other heavy metals, exhibiting extremely high enrichment, mainly due to human factors during the whole sampling period. The results of the pollution load index indicated that the proportions of the number of highly and very highly polluted PM2.5-bound metals were the highest during the heating period, while the proportion of moderately polluted PM2.5-bound metals was the highest during the non-heating period. The combined pollution degree of heavy metals was more serious during the heating period. Third, according to the health risk assessment model, we concluded that the non-carcinogenic and carcinogenic risks caused by inhalation exposure were the highest and by dermal exposure were the lowest for all kinds of people. The overall non-carcinogenic risk of heavy metals via inhalation and subsequent ingestion exposure caused significant harm to children during the non-heating and the heating periods, and the risk values were 2.64, 4.47, 1.20 and 1.47, respectively. Pb and Cr exhibited the biggest contributions to the non-carcinogenic risk. All the above non-carcinogenic risks exceeded the standard limits suggested by EPA (HI or HQ < 1). The carcinogenic risk via inhalation exposure to children, adult men and women were 2.10 × 10−4, 1.80 × 10−4, and 1.03 × 10−4 during the...
Yixuan Liu; Shanshan Li; Chunyuan Sun; Mengxi Qi; Xue Yu; Wenji Zhao; Xiaoxiu Li. Pollution Level and Health Risk Assessment of PM2.5-Bound Metals in Baoding City Before and After the Heating Period. International Journal of Environmental Research and Public Health 2018, 15, 2286 .
AMA StyleYixuan Liu, Shanshan Li, Chunyuan Sun, Mengxi Qi, Xue Yu, Wenji Zhao, Xiaoxiu Li. Pollution Level and Health Risk Assessment of PM2.5-Bound Metals in Baoding City Before and After the Heating Period. International Journal of Environmental Research and Public Health. 2018; 15 (10):2286.
Chicago/Turabian StyleYixuan Liu; Shanshan Li; Chunyuan Sun; Mengxi Qi; Xue Yu; Wenji Zhao; Xiaoxiu Li. 2018. "Pollution Level and Health Risk Assessment of PM2.5-Bound Metals in Baoding City Before and After the Heating Period." International Journal of Environmental Research and Public Health 15, no. 10: 2286.
Accurate island road centerlines are important to tourism planning, resource development, and other applications. However, high-resolution island imaging is highly detailed with complex features, which increases the difficulty of road centerline extraction. To address the problem, we propose a method based on a multiscale united feature, which can improve the extraction of road centerlines in high-resolution island images. First, a biological simulation saliency algorithm is used to determine the island extent. Then, the spectral, geometric, and texture features of roads in high-resolution images are fully utilized, and a multiscale united feature is generated by the effective combination of the features to enhance road characteristics. Road regions are extracted by the implementation of the united feature. Finally, with the advantage of reconstruction ability within strong noise, a tensor voting algorithm is applied to refine the road regions, and then, the road centerline is extracted. The following conclusions are obtained by comparing the proposed method with three state-of-the-art methods: For a study area in which roads present clear characteristics and are less covered, the proposed method exhibits better road centerline extraction performance, and its completeness, correct rate, and quality index are better than the methods to which it was compared; the same was true for a study area with complicated road distribution. The proposed method can be applied to road centerline extraction of high-resolution island images.
Ran Jing; Zhaoning Gong; Wending Zhu; Hongliang Guan; Wenji Zhao. Island Road Centerline Extraction Based on a Multiscale United Feature. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2018, 11, 3940 -3953.
AMA StyleRan Jing, Zhaoning Gong, Wending Zhu, Hongliang Guan, Wenji Zhao. Island Road Centerline Extraction Based on a Multiscale United Feature. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 2018; 11 (11):3940-3953.
Chicago/Turabian StyleRan Jing; Zhaoning Gong; Wending Zhu; Hongliang Guan; Wenji Zhao. 2018. "Island Road Centerline Extraction Based on a Multiscale United Feature." IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 11, no. 11: 3940-3953.
Beijing, which is the capital of China, suffers from severe Fine Particles (PM2.5) pollution during the heating season. In order to take measures to control the PM2.5 pollution and improve the atmospheric environmental quality, daily PM2.5 samples were collected at an urban site from 15 November to 31 December 2016, characteristics of PM2.5 chemical compositions and their effect on atmospheric visibility were analyzed. It was found that the daily average mass concentrations of PM2.5 ranged from 7.64 to 383.00 μg m−3, with an average concentration of 114.17 μg m−3. On average, the Organic Carbon (OC) and Elemental Carbon (EC) contributed 21.39% and 5.21% to PM2.5, respectively. Secondary inorganic ions (SNA: SO42− + NO3− + NH4+) dominated the Water-Soluble Inorganic Ions (WSIIs) and they accounted for 47.09% of PM2.5. The mass concentrations of NH4+, NO3− and SO42− during the highly polluted period were 8.08, 8.88 and 6.85 times greater, respectively, than during the clean period, which contributed most to the serious PM2.5 pollution through the secondary transformation of NO2, SO2 and NH3. During the highly polluted period, NH4NO3 contributed most to the reconstruction extinction coefficient (b′ext), accounting for 35.7%, followed by (NH4)2SO4 (34.44%) and Organic Matter (OM: 15.24%). The acidity of PM2.5 in Beijing was weakly acid. Acidity of PM2.5 and relatively high humidity could aggravate PM2.5 pollution and visibility impairment by promoting the generation of secondary aerosol. Local motor vehicles contributed the most to NO3−, OC, and visibility impairment in urban Beijing. Other sources of pollution in the area surrounding urban Beijing, including coal burning, agricultural sources, and industrial sources in the Hebei, Shandong, and Henan provinces, released large amounts of SO2, NH3, and NO2. These, which were transformed into SO42−, NH4+, and NO3− during the transmission process, respectively, and had a great impact on atmospheric visibility impairment.
Xing Li; Shanshan Li; Qiulin Xiong; Xingchuan Yang; Mengxi Qi; Wenji Zhao; Xinlong Wang. Characteristics of PM2.5 Chemical Compositions and Their Effect on Atmospheric Visibility in Urban Beijing, China during the Heating Season. International Journal of Environmental Research and Public Health 2018, 15, 1924 .
AMA StyleXing Li, Shanshan Li, Qiulin Xiong, Xingchuan Yang, Mengxi Qi, Wenji Zhao, Xinlong Wang. Characteristics of PM2.5 Chemical Compositions and Their Effect on Atmospheric Visibility in Urban Beijing, China during the Heating Season. International Journal of Environmental Research and Public Health. 2018; 15 (9):1924.
Chicago/Turabian StyleXing Li; Shanshan Li; Qiulin Xiong; Xingchuan Yang; Mengxi Qi; Wenji Zhao; Xinlong Wang. 2018. "Characteristics of PM2.5 Chemical Compositions and Their Effect on Atmospheric Visibility in Urban Beijing, China during the Heating Season." International Journal of Environmental Research and Public Health 15, no. 9: 1924.
PM2.5 samples from Beijing, Tianjin, and Langfang were simultaneously collected from 20 November 2016 to 25 December 2016, and the organic carbon (OC) and elemental carbon (EC) content in the samples were measured and analyzed. The pollution characteristics and sources of OC and EC in atmospheric PM2.5 for three adjacent cities were discussed. The average mass concentrations of OC in PM2.5 in Beijing, Tianjin, and Langfang were 27.93 ± 23.35 μg/m3, 25.27 ± 12.43 μg/m3, and 52.75 ± 37.97 μg/m3, respectively, and the mean mass concentrations of EC were 6.61 ± 5.13 μg/m3, 6.14 ± 2.84 μg/m3, and 12.06 ± 6.81 μg/m3, respectively. The average mass concentration of total carbon (TC) accounted for 30.5%, 24.8%, and 49% of the average mass concentration of PM2.5 in the atmosphere. The total carbonaceous matter (TCA) in Beijing, Tianjin, and Langfang was 51.29, 46.57, and 96.45 μg/m3, respectively. The TCA was the main component of PM2.5 in the region. The correlation between OC and EC in the three cities showed R2 values of 0.882, 0.633, and 0.784 for Beijing, Tianjin, and Langfang, respectively, indicating that the sources of urban carbonaceous aerosols had good consistency and stability. The OC/EC values of the three sampling points were 4.48 ± 1.45, 4.42 ± 1.77, and 4.22 ± 1.29, respectively, considerably greater than 2, indicating that the main sources of pollution were automobile exhaust, and the combustion of coal and biomass. The OC/EC minimum ratio method was used to estimate the secondary organic carbon (SOC) content in Beijing, Tianjin and Langfang. Their values were 10.73, 10.71, and 19.51, respectively, which accounted for 38%, 42%, and 37% of the average OC concentration in each city, respectively. The analysis of the eight carbon components showed that the main sources of pollutants in Beijing, Tianjin, and Langfang were exhaust emissions from gasoline vehicles, but the combustion of coal and biomass was relatively low. The pollution of road dust was more serious in Tianjin than in Beijing and Langfang. The contribution of biomass burning and coal-burning pollution sources to atmospheric carbon aerosols in Langfang was more prominent than that of Beijing and Tianjin.
Mengxi Qi; Lei Jiang; Yixuan Liu; Qiulin Xiong; Chunyuan Sun; Xing Li; Wenji Zhao; Xingchuan Yang. Analysis of the Characteristics and Sources of Carbonaceous Aerosols in PM2.5 in the Beijing, Tianjin, and Langfang Region, China. International Journal of Environmental Research and Public Health 2018, 15, 1483 .
AMA StyleMengxi Qi, Lei Jiang, Yixuan Liu, Qiulin Xiong, Chunyuan Sun, Xing Li, Wenji Zhao, Xingchuan Yang. Analysis of the Characteristics and Sources of Carbonaceous Aerosols in PM2.5 in the Beijing, Tianjin, and Langfang Region, China. International Journal of Environmental Research and Public Health. 2018; 15 (7):1483.
Chicago/Turabian StyleMengxi Qi; Lei Jiang; Yixuan Liu; Qiulin Xiong; Chunyuan Sun; Xing Li; Wenji Zhao; Xingchuan Yang. 2018. "Analysis of the Characteristics and Sources of Carbonaceous Aerosols in PM2.5 in the Beijing, Tianjin, and Langfang Region, China." International Journal of Environmental Research and Public Health 15, no. 7: 1483.
Urbanization and industrialization have spurred air pollution, making it a global problem. An understanding of the spatiotemporal characteristics of PM2.5 and PM10 concentrations (particulate matter with an aerodynamic diameter of less than 2.5 μm and 10 μm, respectively) is necessary to mitigate air pollution. We compared the characteristics of PM2.5 and PM10 concentrations and their trends of China, India, and the U.S. from 2014 to 2017. Particulate matter levels were lowest in the U.S., while China showed higher concentrations, and India showed the highest. Interestingly, significant declines in PM2.5 and PM10 concentrations were found in some of the most polluted regions in China as well as the U.S. No comparable decline was observed in India. A strong seasonal trend was observed in China and India, with the highest values occurring in winter and the lowest in summer. The opposite trend was noted for the U.S. PM2.5 was highly correlated with PM10 for both China and India, but the correlation was poor for the U.S. With regard to reducing particulate matter pollutant concentrations, developing countries can learn from the experiences of developed nations and benefit by establishing and implementing joint regional air pollution control programs.
Xingchuan Yang; Lei Jiang; Wenji Zhao; Qiulin Xiong; Wenhui Zhao; Xing Yan. Comparison of Ground-Based PM2.5 and PM10 Concentrations in China, India, and the U.S. International Journal of Environmental Research and Public Health 2018, 15, 1382 .
AMA StyleXingchuan Yang, Lei Jiang, Wenji Zhao, Qiulin Xiong, Wenhui Zhao, Xing Yan. Comparison of Ground-Based PM2.5 and PM10 Concentrations in China, India, and the U.S. International Journal of Environmental Research and Public Health. 2018; 15 (7):1382.
Chicago/Turabian StyleXingchuan Yang; Lei Jiang; Wenji Zhao; Qiulin Xiong; Wenhui Zhao; Xing Yan. 2018. "Comparison of Ground-Based PM2.5 and PM10 Concentrations in China, India, and the U.S." International Journal of Environmental Research and Public Health 15, no. 7: 1382.
Xing Yan; Wenzhong Shi; Zhanqing Li; Zhengqiang Li; Nana Luo; Wenji Zhao; Haofei Wang; Xue Yu. Satellite-based PM2.5 estimation using fine-mode aerosol optical thickness over China. Atmospheric Environment 2017, 170, 290 -302.
AMA StyleXing Yan, Wenzhong Shi, Zhanqing Li, Zhengqiang Li, Nana Luo, Wenji Zhao, Haofei Wang, Xue Yu. Satellite-based PM2.5 estimation using fine-mode aerosol optical thickness over China. Atmospheric Environment. 2017; 170 ():290-302.
Chicago/Turabian StyleXing Yan; Wenzhong Shi; Zhanqing Li; Zhengqiang Li; Nana Luo; Wenji Zhao; Haofei Wang; Xue Yu. 2017. "Satellite-based PM2.5 estimation using fine-mode aerosol optical thickness over China." Atmospheric Environment 170, no. : 290-302.
Ran Jing; Zhaoning Gong; Wenji Zhao; Ruiliang Pu; Lei Deng. Above-bottom biomass retrieval of aquatic plants with regression models and SfM data acquired by a UAV platform – A case study in Wild Duck Lake Wetland, Beijing, China. ISPRS Journal of Photogrammetry and Remote Sensing 2017, 134, 122 -134.
AMA StyleRan Jing, Zhaoning Gong, Wenji Zhao, Ruiliang Pu, Lei Deng. Above-bottom biomass retrieval of aquatic plants with regression models and SfM data acquired by a UAV platform – A case study in Wild Duck Lake Wetland, Beijing, China. ISPRS Journal of Photogrammetry and Remote Sensing. 2017; 134 ():122-134.
Chicago/Turabian StyleRan Jing; Zhaoning Gong; Wenji Zhao; Ruiliang Pu; Lei Deng. 2017. "Above-bottom biomass retrieval of aquatic plants with regression models and SfM data acquired by a UAV platform – A case study in Wild Duck Lake Wetland, Beijing, China." ISPRS Journal of Photogrammetry and Remote Sensing 134, no. : 122-134.
This study aims to investigate the concentration levels, pollution characteristics and the associated potential ecological risks of the heavy metals found in dust in the metropolitan area of Beijing, China during the winter. Dust samples were collected at 49 different spatial locations of Beijing’s metropolitan area from November 2013 to January 2014, in which the concentration levels of Cd, Cr, Pb, Cu, Zn, Ni, Co, V, Bi and Mo were measured by Elan DRC II type inductively coupled plasma mass spectrometry (ICP-MS). Test results showed that the concentrations of dust heavy metals Pb, Cr, Cu and Zn in the urban areas (147.1 mg·kg−1, 195.9 mg·kg−1, 239.2 mg·kg−1 and 713.2 mg·kg−1) were significantly higher than those in the suburbs (91.6 mg·kg−1, 125.1 mg·kg−1, 131.9 mg·kg−1 and 514.5 mg·kg−1). Enrichment factors and the geo-accumulation index were used to describe the pollution characteristics of dust heavy metals in urban and suburban areas. Results indicated that Zn and Cu were moderately polluting in both urban and suburban areas, Cd was severely polluting in urban areas and heavily polluting in the suburbs. Furthermore, potential ecological risk assessment revealed that the degrees of ecological harm of dust heavy metals were very strong in both urban and suburban areas, but especially in urban areas. The potential ecological risk of heavy metal Cd, whose single factor of ecological damage was extremely strong, accounted for about 90% of the total ecological risk.
Qiulin Xiong; Wenji Zhao; Jiayin Zhao; Wenhui Zhao; Lei Jiang. Concentration Levels, Pollution Characteristics and Potential Ecological Risk of Dust Heavy Metals in the Metropolitan Area of Beijing, China. International Journal of Environmental Research and Public Health 2017, 14, 1159 .
AMA StyleQiulin Xiong, Wenji Zhao, Jiayin Zhao, Wenhui Zhao, Lei Jiang. Concentration Levels, Pollution Characteristics and Potential Ecological Risk of Dust Heavy Metals in the Metropolitan Area of Beijing, China. International Journal of Environmental Research and Public Health. 2017; 14 (10):1159.
Chicago/Turabian StyleQiulin Xiong; Wenji Zhao; Jiayin Zhao; Wenhui Zhao; Lei Jiang. 2017. "Concentration Levels, Pollution Characteristics and Potential Ecological Risk of Dust Heavy Metals in the Metropolitan Area of Beijing, China." International Journal of Environmental Research and Public Health 14, no. 10: 1159.
With the fast development of the economy and expansion, a large number of people have concentrated in Beijing over the past few decades, leading to the result that Beijing has become home to one of the most complex mixtures of aerosol types in the world. The various aerosol types play different roles in the determination of global climate change, visibility, and human health. However, to the best of our knowledge, research has rarely analyzed the correlation between aerosol types and air quality index (AQI) in Beijing (urban and suburban) over a long-term series of observations. Therefore, in this study, we aim to identify and discuss the different aerosol types and AQI in Beijing from 2004 to 2015. The aerosol types are classified into six categories: dust, mixed, highly-absorbing, moderately-absorbing, slightly-absorbing, and scattering by a multiple clustering method with the fine mode fraction (FMF) and single scattering albedo (SSA) data of retrievals from the global Aerosol Robotic Network (AERONET) sun photometer sites. The AQI levels: are good (0–50); moderate (51–100); unhealthy for sensitive groups (101–150); unhealthy (151–200); very unhealthy (201–300); and hazardous (>300). The results show that a significant FMF variability occurred among different seasons in Beijing, with maximum values present in spring and minimum values in winter. The SSA values exhibit variation, with small fluctuations from season to season. In the case of BJ station, the scattering aerosols are more frequent in summer (39%) and less in winter (1%), while the coarse particles (dust) are more frequent in spring (18%) and less in autumn (6%). In contrast, the absorbing aerosols (especially slightly-absorbing) are more frequent in summer (35%) and winter (15%). However, the mixed aerosol types are more frequent in spring (38%) and less in summer (8%). There is a similar seasonal variation in XH. In the past 12 years, the slightly-absorbing aerosol type in Beijing has increased by approximately 14%, which is believed to be due to the rapid development of industrial cities. In addition, comparing the urban and suburban regions, the slightly-absorbing aerosol type is the dominant aerosol type in both areas. Furthermore, to identify the dominant aerosol types which lead to air pollution, a related analysis was carried out by analyzing different aerosol types and the relationship between aerosol types and AQI. The results indicate that the air pollution was strongly correlated to slightly-absorbing aerosols, in which the percentage of slightly-absorbing aerosols was about 49% during the hazardous days in 2013–2015, and the correlation between AQI and aerosol types is also strong (R2 = 0.76 and 0.97, in Beijing and Xianghe).
Yang Ou; Wenhui Zhao; Junqian Wang; Wenji Zhao; Bo Zhang. Characteristics of Aerosol Types in Beijing and the Associations with Air Pollution from 2004 to 2015. Remote Sensing 2017, 9, 898 .
AMA StyleYang Ou, Wenhui Zhao, Junqian Wang, Wenji Zhao, Bo Zhang. Characteristics of Aerosol Types in Beijing and the Associations with Air Pollution from 2004 to 2015. Remote Sensing. 2017; 9 (9):898.
Chicago/Turabian StyleYang Ou; Wenhui Zhao; Junqian Wang; Wenji Zhao; Bo Zhang. 2017. "Characteristics of Aerosol Types in Beijing and the Associations with Air Pollution from 2004 to 2015." Remote Sensing 9, no. 9: 898.
Road selection is a critical component of road network generalization that directly affects its accuracy. However, most conventional selection methods are based solely on either a linear or an areal representation mode, often resulting in low selection accuracy and biased structural selection. In this paper we propose an improved hybrid method combining the linear and areal representation modes to increase the accuracy of road selection. The proposed method offers two primary advantages. First, it improves the stroke generation algorithm in a linear representation mode by using an ordinary least square (OLS) model to consider overall information for the roads to be connected. Second, by taking advantage of the areal representation mode, the proposed method partitions road networks and calculates road density based on weighted Voronoi diagrams. Roads were selected using stroke importance and a density threshold. Finally, experiments were conducted comparing the proposed technique with conventional single representation methods. Results demonstrate the increased stroke generation accuracy and improved road selection achieved by this method.
Jianchen Zhang; Yanhui Wang; Wenji Zhao. An Improved Hybrid Method for Enhanced Road Feature Selection in Map Generalization. ISPRS International Journal of Geo-Information 2017, 6, 196 .
AMA StyleJianchen Zhang, Yanhui Wang, Wenji Zhao. An Improved Hybrid Method for Enhanced Road Feature Selection in Map Generalization. ISPRS International Journal of Geo-Information. 2017; 6 (7):196.
Chicago/Turabian StyleJianchen Zhang; Yanhui Wang; Wenji Zhao. 2017. "An Improved Hybrid Method for Enhanced Road Feature Selection in Map Generalization." ISPRS International Journal of Geo-Information 6, no. 7: 196.
Chinese urban agglomeration (UA) has gradually become a new world economic center and the strategic region of the “The Belt and Road Initiatives”. The spatial patterns and variations of ecology–production–living land (EPL) profoundly affect UA’s development and its ecological environment. Unfortunately, scientific understanding about the trajectories, patterns and drivers of EPL changes in Chinese urban agglomerations (UAs) since reform and opening up is still very limited. The aim of this paper was to monitor those characteristics during the last 35 years. Here, we proposed a new classification system of EPL, including ecology land (EL), industrial production land (IPL), agricultural production land (APL), urban living land (ULL) and rural living land (RLL) due to Chinese urban–rural dual structure. Then, we extracted EPL land from the Chinese LUCC product, which is the recently released remote sensing data product of high resolution spatial land use data in China at national level. Furthermore, we analyzed the spatial-temporal trajectories and driving factors of EPL for Chinese UAs during 1980–2015. The results showed that: (1) ULL and IPL in Chinese UAs were increased rapidly, while EL and APL were seriously decreased. (2) The growth patterns of ULL and IPL had shown a spatial heterogeneity. As to different regional UAs, the expansion rates of ULL and IPL ranked from high to low were as follows: eastern, central, western, and northeastern UAs. (3) National policies, population, and economy dominated the spatial-temporal changes of EPL in Chinese UAs. (4) The multi-planning integration in the structure of land use should be strengthened at UA-scale.
Shisong Cao; Deyong Hu; Wenji Zhao; You Mo; Shanshan Chen. Monitoring Spatial Patterns and Changes of Ecology, Production, and Living Land in Chinese Urban Agglomerations: 35 Years after Reform and Opening Up, Where, How and Why? Sustainability 2017, 9, 766 .
AMA StyleShisong Cao, Deyong Hu, Wenji Zhao, You Mo, Shanshan Chen. Monitoring Spatial Patterns and Changes of Ecology, Production, and Living Land in Chinese Urban Agglomerations: 35 Years after Reform and Opening Up, Where, How and Why? Sustainability. 2017; 9 (5):766.
Chicago/Turabian StyleShisong Cao; Deyong Hu; Wenji Zhao; You Mo; Shanshan Chen. 2017. "Monitoring Spatial Patterns and Changes of Ecology, Production, and Living Land in Chinese Urban Agglomerations: 35 Years after Reform and Opening Up, Where, How and Why?" Sustainability 9, no. 5: 766.
The fine-mode fraction (FMF) can be a useful tool to separate natural aerosols from man-made aerosols and to assist in estimating surface concentrations of particulate matter with a diameter < 2.5 μm. A LookUp Table-based Spectral Deconvolution Algorithm (LUT-SDA) was developed here for satellite-based applications using data such as MODerate resolution Imaging Spectroradiometer (MODIS) measurements. This method was validated against ground-based FMF retrievals from the Aerosol Robotic Network (AERONET). The LUT-SDA was then applied to two MODIS-retrieved aerosol optical thickness (AOT) products for the period of December 2013 to July 2015: the MODIS Collection 6 (C6) Dark Target (DT) AOT product and the simplified high-resolution MODIS Aerosol Retrieval Algorithm (SARA) AOT product. In comparison with the MODIS C6 FMF product in three study areas (Beijing, Hong Kong, and Osaka), FMFs estimated by the LUT-SDA agreed more closely with those retrieved from the AERONET with a very low bias. Eighty percent of the FMF values fell within the expected error range of ± 0.4. The root mean square error (RMSE) was 0.168 with few anomalous values, whereas the RMSE for the MODIS FMF was 0.340 with more anomalous values. The LUT-SDA FMF estimated using SARA AOT data conveys more detailed information on urban pollution than that from MODIS C6 DT AOT data. As a demonstration, the seasonally-averaged spatial distribution of the FMF in Beijing was obtained from the LUT-SDA applied to SARA AOT data and compared with that of the AERONET-retrieved FMF. Their seasonal trends agreed well.Department of Land Surveying and Geo-Informatic
Xing Yan; Zhanqing Li; Wenzhong Shi; Nana Luo; Taixia Wu; Wenji Zhao. An improved algorithm for retrieving the fine-mode fraction of aerosol optical thickness, part 1: Algorithm development. Remote Sensing of Environment 2017, 192, 87 -97.
AMA StyleXing Yan, Zhanqing Li, Wenzhong Shi, Nana Luo, Taixia Wu, Wenji Zhao. An improved algorithm for retrieving the fine-mode fraction of aerosol optical thickness, part 1: Algorithm development. Remote Sensing of Environment. 2017; 192 ():87-97.
Chicago/Turabian StyleXing Yan; Zhanqing Li; Wenzhong Shi; Nana Luo; Taixia Wu; Wenji Zhao. 2017. "An improved algorithm for retrieving the fine-mode fraction of aerosol optical thickness, part 1: Algorithm development." Remote Sensing of Environment 192, no. : 87-97.
As an essential component of the Earth-atmosphere system, aerosols have important impacts on the atmospheric environment and human health. Based on the data sourced from Landsat 8 satellite images, the goal of this paper is to retrieve aerosol optical depth (AOD) in the Beijing area by means of the MODIS Dark Target (DT) Method and the visible near-infrared (VNIR) atmospheric correction method (ACM), of which the accuracy is verified by observation data from AERONET. Furthermore, analysis was conducted to assess the effects of the two specific inversion methods on AOD values and AOD distribution characteristics in Beijing. The results indicate the following: 1) both the DT method and the VNIR method can be used successfully in the inversion of AOD in Beijing with Landsat 8 satellite data, while the DT method generates a slightly higher accuracy than that of the VNIR method, in which the root mean squared error (RMSE) values are 0.195 and 0.282, respectively; 2) AOD distribution in Beijing is presented with significant regional features, in which the areas with high AOD values were mainly concentrated in six districts (Dongcheng, Xicheng, Chaoyang, Fengtai, Haidian, and Shijingshan) and their surrounding areas. In addition, the AOD values are relatively low in the southwestern and northern regions of Beijing, which was mainly due to minor impacts of human activity and transportation.Department of Land Surveying and Geo-Informatic
Yang Ou; Fantao Chen; Wenji Zhao; Xing Yan; Qianzhong Zhang. Landsat 8-based inversion methods for aerosol optical depths in the Beijing area. Atmospheric Pollution Research 2017, 8, 267 -274.
AMA StyleYang Ou, Fantao Chen, Wenji Zhao, Xing Yan, Qianzhong Zhang. Landsat 8-based inversion methods for aerosol optical depths in the Beijing area. Atmospheric Pollution Research. 2017; 8 (2):267-274.
Chicago/Turabian StyleYang Ou; Fantao Chen; Wenji Zhao; Xing Yan; Qianzhong Zhang. 2017. "Landsat 8-based inversion methods for aerosol optical depths in the Beijing area." Atmospheric Pollution Research 8, no. 2: 267-274.
In order to acquire the pollution feature and regularities of distribution of metals in the topsoil within the sixth ring road in Beijing, a total of 46 soil samples were collected, and the concentrations of twelve elements (Nickel, Ni, Lithium, Li, Vanadium, V, Cobalt, Co, Barium, Ba, Strontium, Sr, Chrome, Cr, Molybdenum, Mo, Copper, Cu, Cadmium, Cd, Zinc, Zn, Lead, Pb) were analyzed. Geostatistics and multivariate statistics were conducted to identify spatial distribution characteristics and sources. In addition, the health risk of the analyzed heavy metals to humans (adult) was evaluated by an U.S. Environmental Protection Agency health risk assessment model. The results indicate that these metals have notable variation in spatial scale. The concentration of Cr was high in the west and low in the east, while that of Mo was high in the north and low in the south. High concentrations of Cu, Cd, Zn, and Pb were found in the central part of the city. The average enrichment degree of Cd is 5.94, reaching the standard of significant enrichment. The accumulation of Cr, Mo, Cu, Cd, Zn, and Pb is influenced by anthropogenic activity, including vehicle exhaustion, coal burning, and industrial processes. Health risk assessment shows that both non-carcinogenic and carcinogenic risks of selected heavy metals are within the safety standard and the rank of the carcinogenic risk of the four heavy metals is Cr > Co > Ni > Cd.
Chunyuan Sun; Wenji Zhao; Qianzhong Zhang; Xue Yu; Xiaoxia Zheng; Jiayin Zhao; Ming Lv. Spatial Distribution, Sources Apportionment and Health Risk of Metals in Topsoil in Beijing, China. International Journal of Environmental Research and Public Health 2016, 13, 727 .
AMA StyleChunyuan Sun, Wenji Zhao, Qianzhong Zhang, Xue Yu, Xiaoxia Zheng, Jiayin Zhao, Ming Lv. Spatial Distribution, Sources Apportionment and Health Risk of Metals in Topsoil in Beijing, China. International Journal of Environmental Research and Public Health. 2016; 13 (7):727.
Chicago/Turabian StyleChunyuan Sun; Wenji Zhao; Qianzhong Zhang; Xue Yu; Xiaoxia Zheng; Jiayin Zhao; Ming Lv. 2016. "Spatial Distribution, Sources Apportionment and Health Risk of Metals in Topsoil in Beijing, China." International Journal of Environmental Research and Public Health 13, no. 7: 727.