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Assessment regarding Intaglio Area Trueness associated with Interim Tooth Capped teeth Fabricated using SLA Animations Stamping, DLP 3 dimensional Stamping, as well as Mincing Technology.
To investigate the vertical distribution of atmospheric formaldehyde in the Pearl River Delta (PRD) urban area, simultaneous measurements were performed at three heights on Canton Tower for the first time. Carbonyls including formaldehyde were sampled with 2,4-dinitrophenylhydrazin (DNPH) at noon for 32 days in autumn of 2018, and then analyzed using high-performance liquid chromatography (HPLC). QX77 in vitro Average mass concentrations of formaldehyde at ground level, 118 m, and 488 m sites at Canton Tower were (5.10±1.93), (6.61±2.84), and (5.33±2.55) μg·m-3, respectively. The measured formaldehyde was positively correlated with atmospheric oxidant O x at the three sites (R 0.65-0.75), indicating that photochemical formation is an important source for urban formaldehyde in PRD. Three different profiles were found for formaldehyde vertical distribution during the measurements. The most frequently observed one showed a higher value at 118 m while lower ones at ground level and 488 m, occurring when the boundary layer is in moderate convection state with high photochemical reactivity. The 118 m layer may be also influenced by transported high-chimney emissions from industries in suburban areas. Vertical columns of formaldehyde were also calculated according to its vertical profile. The average value was (11.23±4.80)×1015 molecules·cm-2, 19% lower than that from satellite retrieval, while in the same magnitude as values reported in reference papers.A passive air sampler was used to monitor the concentration and contamination profile of 18 polychlorinated biphenyls (PCBs) in the atmosphere over the urban and industrial area of Gaolan, a city in northwest China, during the non-heating and heating seasons of 2018, and the sources, pollutant transport, and the health risks of PCB exposure were analyzed and assessed using principle component analysis, trajectory modeling, and inhalation exposure modeling. The atmospheric concentration in the study area ranged from 110.2 to 429.9 pg·m-3, and the highest average concentration was found at the industrial estate. Tetra-PCBs and penta-PCBs were the dominant homologue groups, and the percentage of tetra-PCBs increased in the heating season. Combustion and industrial thermal processes, PCB-containing electrical equipment, and the combined source of volatilization from paint, combustion, and industrial thermal processes were considered to be the main sources, and the source of combustion and industrial thermal processes contributed the largest proportion of PCBs at 40.8%. Largely, the emission of UP-PCBs would significantly influence PCB pollution in the study area. Trajectory analysis results illustrated that PCBs emitted from sources in the study area would be transmitted to Lanzhou City atmospherically; local pollution would be the main source of PCBs contamination in the study area during the non-heating season, while the atmospheric input of PCBs transmitted from the northwest region would be another source during the heating season. Health risk analysis showed that the non-cancer risk of PCBs exposure was low in all age groups; however, lifetime cancer risks exceeded 10-6. PCBs emitted from combustion and industrial thermal processes sources would have a strong impact on resident exposure to PCBs, and adverse health effects would be caused due to long-term inhalation exposure of the inhabitants to PCBs contamination in the study area.Architectural decoration is an important anthropogenic emission source of VOCs in China, and there are few studies on the emission of VOCs from architectural adhesives. In this study, the VOCs content level and emission factors of various architectural adhesives were measured and then, a VOC emission inventory of architectural adhesives in China from 2013 to 2017 was established by a top-down emission factor method. Results showed that the comprehensive VOCs emission factor of architectural adhesives was 97.0 kg·t-1, of which 543 kg·t-1 was from solvent-based architectural adhesives, 45 kg·t-1 was from water-based architectural adhesives, and 63 kg·t-1 was from bulk architectural adhesives. The VOCs emissions from architectural adhesives were 165 kt, 181 kt, 188 kt, 201 kt, and 219 kt from 2013 to 2017 in China. The contribution of VOCs emission of various disparate architectural adhesives was 25.5%, 23.6%, and 50.9% for water-based, bulk, and solvent-based types, respectively. Shandong, Jiangsu, Zhejiang, Sichuan, Guangdong, Henan, Yunnan, and Fujian provinces contributed significant amounts, with a total emission of 120 kt in 2017, accounting for nearly 55% of the total VOCs emission for architectural adhesives.Based on data from industrial activities and environmental surveys in the six districts of Xiamen, the emission inventory of industrially sourced volatile organic compounds (VOCs) from eight industries in the six districts of Xiamen was calculated for 2019 by applying the emission factor analysis method. The spatial distribution pattern of VOC emission intensity in the six districts of Xiamen was analyzed. VOCs treatment technologies applied in the industries in the VOCs emission inventory were analyzed and countermeasures for improving VOC control were proposed based on the survey of the industries. The results showed that the total VOCs production and VOCs emission from industrial sources in Xiamen was 16027.88 t and 5514.58 t in 2019, respectively. Among them, the VOCs emission from Haicang, Tong'an, Xiang'an, and Jimei districts outside Xiamen Island were 1648.35, 2111.13, 667.52, and 750.48 t, respectively. Fewer VOC emissions from Xiamen Island were observed, which included 292.42 and 44.68 t from Huli and Siming districts, respectively. Except for the Huli District, the spatial distribution of emissions showed a spatial characteristic that the VOCs emission intensities outside Xiamen Island are higher than that of Xiamen Island. Among the eight industries in Xiamen, VOCs emissions were mainly from coating, printing, chemical, and rubber industries, which accounted for 51.21%, 20.18%, 13.63%, and 10.67%, respectively, of the total emissions. The analytic results of the VOCs waste gas disposal technique in Xiamen indicate that, from the perspective of source control, enterprises can effectively control the generation and emission of the VOCs at the source by using low (zero) raw materials. For the terminal disposal procedure, the actual disposal efficiency of UV photolysis/photocatalysis, low-temperature plasma, and biological methods are all lower than 80%, and that of the combined technique of adsorption and catalytic combustion, and the combustion method are both higher than 90%.
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