Papers by Keyword: Nitrogen Dioxide

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Authors: Nurul Izma Mohammed, Nurfadhilah Othman, Khairul Bariyah Baharuddin
Abstract: Complaints on poor air quality in an enclosed car park have been raised up among the public, which might cause serious health effects to the drivers, passengers, and labours who are working at the premises. Improper design of mechanical ventilation systems in a car park would result in a poor indoor environment. The exhaust emission of motor vehicle contains a variety of potentially harmful substances encompassing carbon monoxide, nitrogen oxides, sulphur dioxide, hydrocarbons, and fine particulates. In Kuala Lumpur, there is a great demand but a short supply of lands and building spaces. Thus, a large multi-storey underground car parks is a common solution for both, the government and developers. Although the health effects of the motor vehicle emissions and ambient air pollution are already known, but due to the nature of enclosed multi-storey car parks, these health risks are predicted to be intensified. Thus, it is crucial to investigate and evaluate the status of the air pollution in the enclosed car parks with emphasis on sulphur dioxide (SO2) and nitrogen dioxides (NO2). Samples were collected in one of the famous shopping malls in Kuala Lumpur using a GrayWolf Advanced Sense Direct Sense; Toxic Gas Test Meters from 8 am until 5 pm on weekdays and weekends. The results demonstrate that the concentrations of SO2 and NO2 on weekends is higher than weekdays. Besides, the concentrations for both weekdays and weekends have exceeded the standard limit set by the Malaysian Ambient Air Quality Guideline (MAAQG).
Authors: Z. Ling, Colin Leach, Robert Freer
Authors: Yutaka Adachi, Isao Sakaguchi, Haruki Ryouken, Naoki Ohashi, Hajime Haneda, Tadashi Takenaka
Authors: S. Novikov, Yu.N. Makarov, Heikki Helava, S. Lebedev, Andrey Lebedev, Valeri Davydov
Abstract: Graphene films were grown on SiC substrates by annealing in vacuum or in Ar flow. Gas sensors based on graphene films were made and tested on response to nitrogen dioxide. Graphene film is used in the sensor. The graphene film grown by annealing in Ar flow shows superior sensitivity compared to that annealed in vacuum. Both sensors exhibit good potential for environmental research and monitoring
Authors: Xiao Li Bai, Guang Na Zhang, Duo Wang, Shao Fen Guo, Xian Gui Zhu
Abstract: The daily pollutant variations of PM2.5, PM10, SO2 and NO2 are useful for environment protection and advices for human health. Two years data from three different time period before Spring Festival (SF), after SF and after Lantern Festival (LF) in Shenyang city of year 2013 and 2014 was analyzed. Results showed that concentrations of PM2.5, PM10, SO2 and NO2 were higher in 2014 than those in 2013, especially for SO2 and NO2; Among the three periods, concentrations of four air pollutants followed the sequence of after LF > before SF > after SF and road traffic emissions are more contributive than firework combustion during the festival celebration. We conclude that air pollution in Shenyang City is worsening and more influenced by vehicular pollution.
Authors: J. Brunet, A. Pauly, M. Dubois, C. Varenne, K. Guerin, A. Ndiaye
Abstract: A new hybrid material performed by the immobilization of indigo particles on nanocarbonaceous matrix has been developed, characterized and implemented with chemoresistors. If phthalocyanine-based chemoresistors provide a high sensitivity, a low threshold of detection and a partial selectivity towards oxidizing pollutants, indigo/nanocarbons hybrid material acts as a selective ozone filter from air sample and so strongly enhances the sensor selectivity towards nitrogen dioxide. The functionalization, highlighted by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis, occurs in a non-covalent way and proceeds through pi-stacking interactions. With filtering yields higher than 99.5% for ozone and less than 5% for nitrogen dioxide, indigo adsorbed onto multi-wall carbon nanotubes has been identified as the most selective filtering material while exhibiting a much greater durability than indigo or nanotubes separately. Associated to phthalocyanine-based gas sensor, the sustainable, selective and real-time monitoring of NO2 in ppb range has been successfully achieved.
Authors: Tatiana Myasoedova, G.E. Yalovega, V.V. Petrov, O.V. Zabluda, V.A. Shmatko, A.O. Funik
Abstract: SiOxCuOy thin films were prepared by the deposition on to the Si/SiO2 substrates from the alcoholic solutions employing the sol-gel technique. The various analytic techniques were applied to characterize structure and properties of the films under study . The both X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies showed the presence CuO as well as CuO2 phases and formation of a dual-oxide CuSiO3 with the average crystallites sizes of 35-50 nm. The conductance of the films was rather sensitive to the presence of 1-20 ppm NO2 concentration at the operating temperatures in the range of 20–200 C.
Authors: Rawat Jaisutti, Juagwon Theerasak, Onanong Chamlek, Tanakorn Osotchan
Abstract: Copper Phthalocyanine (CuPc) thin films have a potential to use as nitrogen dioxide (NO2) gas sensor therefore the study of property modification of CuPc thin film by NO2 gas can lead to a better understanding the sensor operation. CuPc thin films were prepared by thermal vacuum deposition on glass substrate and aluminum interdigitated electrodes. The film characteristics were investigated with and without NO2 gas. These characteristics indicated that the resistance of CuPc film decrease as the NO2 concentration increases. In order to achieve high efficient of sensing properties, the post-deposition film was also annealed. The surface modifications were investigated with different exposed time of NO2 gas. Their properties modifications before and after annealing were investigated on the film morphology and crystalline structure. The surface morphology of the film was examined by atomic force microscopy while the crystalline structure of the film was determined by x-ray diffraction. The electrical measurements of CuPc film exposed to NO2 gas were studied in order to investigate property modification of the CuPc film.
Authors: Zhao Long Huang, Shao Ping Feng, Su Yan Yin, Li Zen Hui, Ying He, Yan Jiang
Abstract: The conditions of oxidation of nitrite by manganese dioxide in the solution was studied, with sodium nitrite was used as the sample, respectively. Experiment results showed that the stronger oxidation to nitrite in strong acid, but nitrous acid is instable, escaping NO2 out from the solution. When pH=3.5, the oxidation rate of nitrite with manganese dioxide was better. The concentration of nitrite tended forward to be stable after 30min. After reaction, the oxidizing power of manganese dioxide which was treated by dilute sulfuric acid wasn't enhanced. The manganese dioxide treated by acid reacted with fresh nitrite solution and the effect wasn't good. The process of oxidation could be go on and the concentration of nitrite would decrease obviously when fresh manganese dioxide used to react the same original nitrite. Maybe some active sites exist at the surface of manganese dioxide. When the reaction equilibrium was reached, the active point at the surface of manganese dioxide would probably have disappeared. The property of oxidation of manganese dioxide to nitrite could be used in treat NO2 and nitrite. Combining the two methods which absorption of NO2 by base and oxidation of NO2 or nitrite by manganese dioxide, NO2 would be treated completely and treatment cost would be lower.
Authors: Tao Meng, Zhen Zhen Huang, Xiao Qian Qian, Peng Lai Zhu, Ya Chao Yu
Abstract: The photo-catalytic efficiency and durability of nano-TiO2 photo-catalytic cementitious materials for oxidizing nitrogen dioxide were investigated under simulated sunlight irradiation. The experimental results showed that the photo-catalytic efficiency increased with increase of the content of nano-TiO2. When 15wt% nano-TiO2 was added, the photo-catalytic efficiency was equal to 223% of that of standard cement. When activated carbon was used as the carrier of nano-TiO2, the photo-catalytic efficiency of cementitious nano-TiO2 could be enhanced markedly. For example, the photo-catalytic efficiency could reach to 85.7%, which was as much as 359% of that of standard cement when the contents of activated carbon and nano-TiO2 were both 10wt%. Compared with nano-TiO2 powder, the photo-catalysis durability of cementitious nano-TiO2 supported by activated carbon could be improved clearly for that activated carbon could absorb nitrogen dioxide effectively, which was favored to the photo-oxidation of nano-TiO2 on nitrogen dioxide.
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