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The increasing emissions of industrial production and transportation have resulted in serious atmospheric heavy-metal pollution, posing threats to the health of urban residents. In this paper, the bryophyte is recommended to monitor the pollution, which features wide distribution, low cost, and being able to get intuitive results. Thus, a kind of moss (Sphagnum palustre) bag was applied to monitoring the concentrations of atmospheric heavy metal (incl. Cd, Cr, Cu, Pb and Zn) in Guangzhou City, and accordingly the pollution degree and health risks were evaluated. The results obtained from the monitoring showed that in comparison with the pre-exposure to the atmospheric heavy metal pollution, the post-exposure geometric mean values of concentrations of Cd, Cu, Pb and Zn contained in the mosses were 1.2, 2.3, 1.4 and 2.3 times higher than, respectively, however Cr concentration decreased slightly (0.9 times); and in general, the geometric mean values of concentrations of Cd, Cu, Pb and Zn were comparatively high in industrial areas, while in commercial areas, the concentrations of Cu, Pb and Zn were found to be higher than the scenic and residential areas. Principal component analysis (PCA) and cluster analysis (CA) revealed that industrial activities and traffic emission were the main sources of atmospheric heavy metal contamination of Guangzhou City. Following the heavy metal pollution status-quo investigation with moss, four functional areas were assessed using the contamination factor, which indicated that in the monitoring sites showing heavy metals (Cu, Pb, Zn) pollution was high/very-high, the emissions mainly came from coal combustion, industrial metal production and processing activities, while those showing moderate (Cu, Zn) pollution, the pollutants came from traffic sources, and the monitoring sites where heavy metal contamination level was low, were utterly distant from industrial emission sources and traffic pollution sources. In conclusion, the moss bag (Sphagnum palustre) is rather adaptive to monitoring atmospheric heavy metal contamination in urban areas. [ABSTRACT FROM AUTHOR]

As urbanization continues, construction-related dust has emerged as a significant contributor to urban air pollution. A comprehensive evaluation of the environmental impact of construction dust necessitates an understanding of the pollution discharge from an urban perspective. Consequently, this paper proposes a construction dust emission inventory construction method from the urban perspective, which combines remote sensing image interpretation and the emission factor method. On this basis, a particulate matter emission inventory of construction dust sources in Guangzhou in 2020 is established, and the emission characteristics of the study area are analyzed using a 2kmx2km grid distribution. The findings of this research provide a crucial data foundation for high-resolution pollutant diffusion simulations and environmental impact assessments. They also offer a macro perspective for observing construction pollution, which can be utilized by the government to monitor and control pollution from an urban perspective. [ABSTRACT FROM AUTHOR]

[Objective] The pile-beam-arch (PBA) method, one among many metro construction techniques, is gradually gaining public favor owing to its unique advantages. These include superb structural stability and a remarkable effect on controlling surface settlement. At the same time, the side pile structure, a key mechanical component of the station, plays an important role in the success or failure of the projects involving PBA method. Most current research mainly focuses on the construction optimization and control countermeasures associated with the PBA method. However, there is a noticeable lack of studies focused on the mechanical behavior of side piles during construction and the principles governing side pile-soil interaction. [Methods] This paper focuses on a subway station project in the Guangzhou area, for which a simplified station model test method using the PBA method has been designed. Concurrently, this test method and numerical simulation have been employed to further investigate the evolution of the construction mechanics behavior of the side pile structure in different excavation processes of the station constructed using the PBA method. The primary focus of this study includes a comparative investigation into the soil pressure behind the piles and the internal force and deformation characteristics of the side piles under various spacing parameters. [Results] The results of this study are the following: 1) Under different pile spacing, stress concentration is most notable at the completion stage of the arch and the excavation stage of the first soil layer. As pile spacings increase, the stress concentration area behind the pile gradually shifts away from the pile position, with the stress peak decreasing correspondingly. 2) The bending moment of the side pile structure gradually increases throughout the construction process. The maximum section of the bending moment gradually migrates downward to the middle of the pile body, resulting in a "bow" distribution feature where the value is larger in the middle and smaller at both ends. Conversely, the axial force of the side pile structure remains relatively stable, presenting a "zigzag" pattern from the start to the end of the excavation. The maximum axial force appears at the junction between the side pile and the embedded stratum. 3) The peak value of the side pile's internal force increases with the pile spacings, and the pile spacings' influence on the side pile structure's axial force is more significant than its impact on the bending moment. As construction progresses, the lateral deformation of the pile body changes from initial "forward" deformation outside the station to final "bulging" deformation inside the station. The peak displacement of the pile body increases significantly with the pile spacing. 4) The stress and deformation of the side piles change most notably in the stage of excavation of the first soil layer. During actual construction, more attention should be paid to this stage, and appropriate lateral lining measures should be taken when necessary to maintain the stability of the station structure. [Conclusions] Through this experiment, the whole process of designing, making, operation testing, and data monitoring of the side pile structure in a metro station using the PBA method is demonstrated for students during the model test. This approach facilitates students' understanding of the mechanics and deformation evolution characteristics of a metro station constructed with the PBA method. [ABSTRACT FROM AUTHOR]

In view of the complex operation requirements of Guangzhou Metro Line 18 and Line 22, such as long sections and Y-type routing, this paper proposes corresponding fast and slow train operation solutions, and conducts data simulation through simulation tests to form a signal system solution under fast and slow train operation modes, providing effective technical support for signal system design of similar projects. [ABSTRACT FROM AUTHOR]

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Objective To study EBV infection in nasopharyngeal carcinoma screening population in Guangzhou and analyze the influencing factors. Methods The data of individuals (aged 20 years and above) having EBV antibody of VCA-IgA and NA1-IgA test in Guangzhou Cadre and Talent Health Management Center were collected. Current status of EBV infection was studied and its influencing factors were analyzed by logistic regression analysis. Results A total of 55 311 subjects were screened, including 35 429 males (64.05%) and 19,882 females (35.95%).The overall EBV infection rate was 8.00%. There was no significant differences in the infection rate between different sex groups (P > 0.05). The infection rate of EBV increased with age, with infection rate of 7.07% in individuals aged 20 ~ 39 years, 7.86% in those aged 40 ~ 59 years, 10.11 % in those of 60 ~ 79 years old, and 10.99% in those aged 5 80 years, showing statistical significance (χ² = 85.487, P < 0.01). Logistic regression analysis showed that EBV infection risk increased significantly with advancing age. The odds of EBV infection in individuals aged 40 ~ 59 years were 10.6% higher compared to those aged 20 ~ 39 years (OR = 1.106, 95% CI: 1.028 ~ 1.190). The odds of EBV infection in individuals aged 60 ~ 79 years were 42.2% higher compared to those aged 20 ~ 39 years (OR = 1.422, 95% CI: 1.288 ~ 1.569). Furthermore, the odds of EBV infection in individuals aged 5 80 years were 53.1% higher compared to those aged 20 ~ 39 years (OR = 1.531, 95% CI: 1.230 ~ 1.906). A prior diagnosis of hypertension significantly increased the odds of EBV infection (OR = 1.105, 95% C7: 1.003 ~ 1.218). However, diabetes history exerted no influence on the outcome of EBV infection (P > 0.05). Conclusions The overall infection rate of EBV in Guangzhou is 8.00%. Advanced age and hypertension history are the risk factors of EBV. The screening and prevention and control of EBV susceptible people should be strengthened. [ABSTRACT FROM AUTHOR]