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Han M.,Tianjin Academy of Environmental science | Han M.,State Environmental Protection Key Laboratory of Odor Pollution Control | Lu X.,Tianjin Academy of Environmental science | Zhao C.,Peking University | And 3 more authors.
Advances in Atmospheric Sciences | Year: 2015

Tianjin is the third largest megacity and the fastest growth area in China, and consequently faces the problems of surface ozone and haze episodes. This study measures and characterizes volatile organic compounds (VOCs), which are ozone precursors, to identify their possible sources and evaluate their contribution to ozone formation in urban and suburban Tianjin, China during the HaChi (Haze in China) summer campaign in 2009. A total of 107 species of ambient VOCs were detected, and the average concentrations of VOCs at urban and suburban sites were 92 and 174 ppbv, respectively. Of those, 51 species of VOCs were extracted to analyze the possible VOC sources using positive matrix factorization. The identified sources of VOCs were significantly related to vehicular activities, which specifically contributed 60% to urban and 42% to suburban VOCs loadings in Tianjin. Industrial emission was the second most prominent source of ambient VOCs in both urban and suburban areas, although the contribution of industry in the suburban area (36%) was much higher than that at the urban area (16%). We conclude that controlling vehicle emissions should be a top priority for VOC reduction, and that fast industrialization and urbanization causes air pollution to be more complex due to the combined emission of VOCs from industry and daily life, especially in suburban areas. © 2015, Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.

Feng W.,Tianjin University | Zou K.-H.,State Environmental Protection Key Laboratory of Odor Pollution Control | Zhai Z.-X.,State Environmental Protection Key Laboratory of Odor Pollution Control
Wuji Cailiao Xuebao/Journal of Inorganic Materials | Year: 2010

The TiO2 nanocrystal particles were prepared by low-temperature method. Firstly, hydrolysis of reactants was promoted with microwave radiation aid, then crystallization could be facilitated through the process of the second microwave radiation or aging in water bath. The characterization results show that the shape of TiO2 nanocrystal is sphere or short column, which are all in pure anatase phase. The kinetic studies indicate that the anatase TiO2 growth can be described as the twice order kinetic equation and the apparent activity energy is 59.47 kJ/mol with two-step microwave radiation, while the kinetic equation is conformed to the third order and the apparent activity energy is 19.44 kJ/mol with ageing process. The above comparison proves that the nanocrystal TiO2 would grow faster in short time with the two-step microwave radiation at low temperature.

Feng W.,Tianjin University | Wang Y.,Tianjin University | Zou K.,State Environmental Protection Key Laboratory of Odor Pollution Control | Jin W.,Tianjin University | Zhai Z.,State Environmental Protection Key Laboratory of Odor Pollution Control
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2010

Assisted with the two-step microwave radiation, the nano-crystal TiO2 photocatalyst was prepared with low temperature (473 K) treatment. The characterization results showed the crystalline TiO2 photocatalyst synthesized by this method had even particle size, single crystal phase, and high specific surface area. More importantly, it had high photo-catalyst activity.

Li C.,Tianjin Academy of Environmental science | Li C.,State Environmental Protection Key Laboratory of Odor Pollution Control | Liu W.,Hebei University of Technology | Zhao J.,Tianjin Academy of Environmental science | And 4 more authors.
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2010

The aim of this work was to establish a Dynamic Dilution Olfactometer, basement of research was national standard GB/T14675-93 and European standard En13725, core process of gas pipeline was flow-mixing of the odor and the pure gas by many MFCs, and compiled automation control software based on the LabVIEW programming language, realized functions of automatic control test schedule and determination of odor. The results show that on the calibration experiment to the dynamic olfactometer by the different concentration CO tracing gas, instrumental instability average Id of all dilution step is 0.92%, instrumental accuracy average Ad is 7.2%, meet to and smaller than European standard Id5% and Ad20%.

Li W.-F.,Tianjin Academy of Environmental Protection Science | Li W.-F.,State Environmental Protection Key Laboratory of Odor Pollution Control | Li C.-J.,Tianjin Academy of Environmental Protection Science | Li C.-J.,State Environmental Protection Key Laboratory of Odor Pollution Control | And 8 more authors.
Research of Environmental Sciences | Year: 2014

Odor pollution is one of the environmental issues that produces the most intense complaints from urban residents in China. Investigation into the odor pollution and gaseous pollutants in the urban ambient air of Tianjin City was carried out. Using the grid method, 40 total monitoring sites covering various functional zones were uniformly allocated in the central urban area and a typical industrial area. In total, 1300 air samples were collected using intensive field sampling methods in each season. The chemical composition and olfactory concentrations in the air samples were respectively analyzed by GC-MS and triangle odor bag method. Ammonia was separately determined by spectrophotometry. The results showed that: 1) Odor concentration values ranged from 0 to 90, and were equally matched between the urban and industrial areas. In summer, the highest percentage (42%) of odor concentrations were less than 10. The odor pollution was more serious in spring and autumn as compared with the other two seasons. In spring and autumn, the percentage of values with odor concentration over 20 was more than 85% and 70%, respectively. 2) Ammonia was the odorant with the highest detection rate. The average values of ρ(NH3) in summer, autumn and spring were 0.070, 0.058 and 0.060 mg/m3, respectively. The average value of ρ(NH3) in the residential and the mixed areas were the highest among all types of functional zones. 3) The distribution of H2S varied with seasons, with the highest detection rate in autumn. ρ(H2S) was in the range of 0.0064-0.2200 mg/m3, with the highest value in the industrial area. The average concentrations in the urban and industrial areas were 0.0140 and 0.0230 mg/m3 respectively. The typical gaseous pollutants were selected by comprehensive and quantitative evaluation of multiple parameters such as environmental concentration, olfactory threshold and detectable rate. Ten volatile substances were identified as ammonia, carbon bisulfide, benzene, toluene, 1, 3-dimethylbenzene, ethylbenzene, 1, 2, 4-trimethylbenzene, alcohol, acetone and isoprene. A multiple linear regression equation between odor sensory concentrations and the selected ten substances was set up, and showed good statistical significance and correlation (P<0.05, R=0.78). This result indicates that these gaseous compounds were the most important substances influencing odor pollution in the urban ambient air. The survey results may provide reference for the establishment of an odor environmental standard.

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