Tang G.,CAS Institute of Atmospheric Physics |
Wang Y.,CAS Institute of Atmospheric Physics |
Li X.,CAS Institute of Atmospheric Physics |
Ji D.,CAS Institute of Atmospheric Physics |
And 2 more authors.
Atmospheric Chemistry and Physics | Year: 2012
The Project of Atmospheric Combined Pollution Monitoring over Beijing and its Surrounding Areas, was an intensive field campaign conducted over Northern China between June 2009 and August 2011 to provide a comprehensive record of ozone (O 3) and nitrogen oxides (NO x) and contribute to an in-depth understanding of air pollution in Northern China and its driving forces. In this campaign, 25 stations in an air-quality monitoring network provided regional-scale spatial coverage. In this study, we analyzed the data on O3 and NO x levels obtained at 22 sites (out of 25 sites due to data availability) over Northern China between 1 September 2009 and 31 August 2010. Our goal was to investigate the O 3 spatial-temporal variations and control strategy in this area. Significant diurnal and seasonal variations were noted, with the highest concentrations typically found at around 03:00 p.m. (local time) and in June. The lowest concentrations were generally found during early morning hours (around 06:00 a.m.) and in December. Compared with July and August, June has increased photochemical production due to decreased cloud cover coupled with reduced O3 loss due to less dry deposition, inducing an O 3 peak appearing in June. The averaged O 3 concentrations were lower in the plains area compared with the mountainous area due to the titration effects of high NO x emissions in urban areas. When the characteristics of O 3 pollution in different regions were distinguished by factor analysis, we found high levels of O 3 that exceeded China's National Standard throughout the plains, especially over Beijing and the surrounding areas. An integrated analysis with emissions data, meteorological data, and topography over Northern China found that the meteorological conditions were the main factors that dominated the spatial variations of O 3, with the presence of abundant emissions of precursors in this area. The smog production algorithm and space-based HCH O/NO 2 column ratio were used to show the O 3-NO x-VOC s sensitivity and examine the control strategy of O 3 over Northern China. The results show that summer O 3 production in the plains and northern mountainous areas was sensitive to VOC s and NOx, respectively. The presented results are intended to provide guidance for redefining government strategies to control the photochemical formation of air pollutants over Northern China and are relevant for developing urban agglomerations worldwide. © Author(s) 2012. CC Attribution 3.0 License.
Chen L.,Tianjin Normal University |
Han T.-T.,Nankai University |
Li T.,Nankai University |
Ji Y.-Q.,Nankai University |
And 2 more authors.
Huanjing Kexue/Environmental Science | Year: 2012
Due to the lack of a prediction model for current wind erosion in China and the slow development for such models, this study aims to predict the wind erosion of soil and the dust emission and develop a prediction model for wind erosion in Tianjin by investigating the structure, parameter systems and the relationships among the parameter systems of the prediction models for wind erosion in typical areas, using the U.S. wind erosion prediction system (WEPS) as reference. Based on the remote sensing technique and the test data, a parameter system was established for the prediction model of wind erosion and dust emission, and a model was developed that was suitable for the prediction of wind erosion and dust emission in Tianjin. Tianjin was divided into 11080 blocks with a resolution of 1×1 km2, among which 7778 dust emitting blocks were selected. The parameters of the blocks were localized, including longitude, latitude, elevation and direction, etc.. The database files of blocks were localized, including wind file, climate file, soil file and management file. The weps.run file was edited. Based on Microsoft Visualstudio 2008, secondary development was done using C++ language, and the dust fluxes of 7778 blocks were estimated, including creep and saltation fluxes, suspension fluxes and PM10 fluxes. Based on the parameters of wind tunnel experiments in Inner Mongolia, the soil measurement data and climate data in suburbs of Tianjin, the wind erosion module, wind erosion fluxes, dust emission release modulus and dust release fluxes were calculated for the four seasons and the whole year in suburbs of Tianjin. In 2009, the total creep and saltation fluxes, suspension fluxes and PM10 fluxes in the suburbs of Tianjin were 2.54×106 t, 1.25×107 t and 9.04×105 t, respectively, among which, the parts pointing to the central district were 5.61×105 t, 2.89×106 t and 2.03×105 t, respectively.
Li P.-H.,Nankai University |
Han B.,Nankai University |
Huo J.,Nankai University |
Lu B.,Nankai University |
And 6 more authors.
Aerosol and Air Quality Research | Year: 2012
Organic and elemental carbon (OC and EC) were measured in PM 2.5 and PM 10 at urban and suburban sites in Tianjin, China, from September 2009 to February 2010. Average PM 2.5 and PM 10 mass levels were 124 and 243 μg/m 3, respectively, with 53% of the PM 10 mass present as PM 2.5. The average OC and EC concentrations in PM 2.5 were 14.5 and 4.3 μg/m 3, respectively, while those in PM 10 were 33 and 6.1 μg/m 3, respectively. Relation of OC and EC to the trace elements As, Zn, K and Pb and principal component analysis indicated that multiple sources contributed to the OC and EC. Secondary organic carbon was found to constitute 46% and 66% of the total organic carbon in PM 2.5 and PM 10, respectively, in autumn and 41% and 56%, respectively in winter. © Taiwan Association for Aerosol Research.
Li T.,Appraisal Center for Environment and Engineering |
Wang H.,Tianjin Academy of Social science |
Deng B.,Tianjin Environmental Monitoring Center |
Ren W.,Oxford Brookes University |
Xu H.,Nankai University
Environmental Impact Assessment Review | Year: 2016
Strategic Environmental Assessment (SEA) has been seen as a preventive and participatory environmental management tool designed to integrate environmental protection into the decision-making process. However, the debate about SEA performance and effectiveness has increased in recent decades. Two main challenges exist in relation to this issue. The first is identifying the key influencing factors that affect SEA effectiveness, and the second is analyzing the relationship between SEA and these influencing factors. In this study, influencing factors were investigated through questionnaire surveys in the Chinese context, and then a Structural Equation Model (SEM) was developed and tested to identify potential links and causal relationships among factors. The associations between the independent factors were divided into direct and indirect causal associations. The results indicate that the decision-making process and policy context directly affect SEA implementation, while information and data sharing, public participation, expertise and SEA institutions are indirectly related with SEA. The results also suggest that a lack of cooperation between different sectors is an obstacle to the implementation of SEA. These findings could potentially contribute to the future management and implementation of SEA or enhance existing knowledge of SEA. The results show that the proposed model has a degree of feasibility and applicability. © 2016 Elsevier Inc.
Gao N.,Tianjin University |
Du Z.-H.,Tianjin University |
Tang M.,Tianjin Environmental Monitoring Center |
Yang J.-W.,Tianjin University |
And 2 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2010
The system performance of tunable diode laser absorption spectroscopy (TDLAS) is affected by the modulation parameters such as modulation index, modulation frequency, scanning amplitude and scanning frequency. There is a lack of definite parameters selection basis in practical measurement. Aiming at this problem, the influence of modulation parameters on second harmonic signals was observed by experiment based on a certain theory in the present paper, and the basis and method of modulation parameters optimization for various system functions and demands were summarized by analyzing the signal characteristic including amplitude, signal to noise ratio, symmetry and peak width. For the system of concentration or temperature detection the amplitude and signal to noise ratio will be taken into prior consideration which require optimum modulation index, lower modulation frequency and lower scanning frequency. In condition of pressure detection deduced by lineshape the signal symmetry and peak width are more important to ascertain the modulation parameters according to practical demands. Scanning amplitude will be adjusted to obtain complete signal waveforms, then scanning frequency can be adjusted according to system speed and accuracy requirement. The result of the experiment provided a definite basis for conforming the working state of such system.
Tang J.,Nankai University |
Bai X.,Nankai University |
Zhang W.,Tianjin Environmental Monitoring Center
Soil and Sediment Contamination | Year: 2011
Cadmium (Cd) pollution in the suburbs of Tianjin, China, was monitored over a period of several years. During this period, 193 soil, 120 vegetable, and 71 rice samples from four suburban districts were analyzed. The Cd content of the soil samples was considerably higher than the background level. Some soil samples from the Dongli and Xiqing districts were even in the S5 (Heavy) and S6 (Severe) pollution levels, with a maximum concentration of 5.20 mg kg -1. The Cd contents of vegetable and rice samples were found to be in the F3 (Intermediate) and F4 (Heavy) pollution levels. Vegetables showed differing abilities to accumulate Cd and can be ranked in the following order: leaf vegetables > rootstalk vegetables > fruit vegetables. The average Cd level in different vegetables ranged from 0.0064 to 0.132 mg kg -1, and a positive relationship (p < 0.05) was found between soil and plant Cd contents. Chinese cabbage and celery were more likely to pose risks to human health, as shown by their higher hazardous quotient (HQ) values. The soil Cd pollution in Tianjin seemed primarily to be caused by wastewater irrigation and the application of sewage sludge to farmlands. Other possible sources include the use of phosphate fertilizer and atmospheric deposition. © Taylor & Francis Group, LLC.
Xiao Z.-M.,Tianjin Environmental Monitoring Center |
Bi X.-H.,Nankai University |
Feng Y.-C.,Nankai University |
Zhu T.,Nankai University |
And 3 more authors.
Research of Environmental Sciences | Year: 2014
Variation characteristics of particle size, chemical composition and pollution source of the ambient particulate matter of Tianjin City in 1985, 2001 and 2011 were analyzed. The results showed that mass ratios of fine particulate matters to PM10 were gradually increasing, from less than 0.51 in 1985 to 0.57 in 2011. Chemical compositions of PM10 significantly changed, evolved from single crustal elements to multiple crustal elements including carbonaceous matters and secondary particles. The dominant components of PM10 were Si, Al, Mg, Ca for 1985, were TC, Si, SO4 2-, Al, Ca for 2001 and were TC, Si, SO4 2-, NO3 -, Ca for 2011, respectively. The change of different chemical compositions has taken on in different styles. The proportion of Si in PM10 decreased sharply first then remained slightly stable, from 28.7% for 1985 to 7.6% for 2011, the percentage of carbon component in PM10 decreased slightly, from 24.9% in 2001 to 17.9% in 2011, while the concentration percentage of secondary particles (SO4 2- and NO3 -) in PM10 remarkably increased from 10.2% in 2001 to 18.3% in 2011.The contribution of soot dust to PM10 decreased from 45% in 1985 to 22% in 2011, while the contribution of open sources, secondary particles and motor vehicle exhausts apparently increased from 29%, 6% and 3% in 1985 to 35%, 16% and 16% in 2011, respectively. Contribution of main sources to ambient particulate matter became more. The type of particle pollution has been changed from soot pollution to mix pollution to complex pollution.
Liu B.,Nankai University |
Liang D.,Nankai University |
Yang J.,Nankai University |
Dai Q.,Nankai University |
And 6 more authors.
Environmental Pollution | Year: 2016
From November 2014 to October 2015, the concentrations of volatile organic compounds (VOCs), O3 and NOx were simultaneously monitored by using online instruments at the air monitoring station belonged to Tianjin Environmental Protection Bureau (TEPB). The results indicated that VOCs concentrations were higher in autumn and lower in spring, while O3 concentrations were higher in summer, and lower in winter. The diurnal variations of VOCs and NOx (NO2 plus NO) showed opposite tendency comparing to that of O3. The concentrations of alkanes were higher (the average of 18.2 ppbv) than that of aromatics (5.3 ppbv) and alkenes (5.2 ppbv), however, the alkenes and aromatics made larger contributions to ozone because of their high reactivity. Tianjin belonged to the VOC-limited region during most of seasons (except summer) according to the VOC/NOx ratios (the 8:1 threshold). The automobile exhaust, industrial emission, liquefied petroleum gas/natural gas (LPG/NG), combustion, gasoline evaporation, internal combustion engine emission and solvent usage were identified as major sources of VOCs by Positive Matrix Factorization (PMF) model in Tianjin, and the contributions to VOCs for the entire year were 23.1%, 19.9%, 18.6%, 10.6%, 8.7%, 5.4% and 4.7%, respectively. The conditional probability function (CPF) analysis indicated that the contributing directions of automobile exhaust and industrial emission were mainly affected by source distributions, and that of other sources might be mainly affected by wind direction. The backward trajectory analysis indicated that the trajectory of air mass originated from Mongolia, which reflected the features of large-scale and long-distance air transport, and that of beginning in Jiangsu, Shandong and Tianjin, which showed the features of small-scale and short-distance. Tianjin, Beijing, Hebei and Northwest of Shandong were identified as major potential source-areas of VOCs by using potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models. © 2016 Elsevier Ltd
PubMed | Nankai University and Tianjin Environmental Monitoring Center
Type: | Journal: Environmental pollution (Barking, Essex : 1987) | Year: 2016
Wang J.,Tianjin Environmental Monitoring Center |
Wang X.,Tianjin Environmental Monitoring Center |
Geng Z.,Tianjin Environmental Monitoring Center |
Zhao Y.,Tianjin Environmental Monitoring Center |
Wang B.,Tianjin Environmental Monitoring Center
Chinese Journal of Environmental Engineering | Year: 2016
Monitoring of the heavy metals in seawater is the focus of ocean monitoring. To avoid the interference and matrix effect induced by high salt concentrations, collision cell inductively coupled plasma mass spectrometry (ORS-ICP-MS) with a standard addition method is highly recommended for determination of heavy metals. This method can efficiently eliminate the matrix effect and interference, and its limits of detection for Cr, Ni, Cu, Zn, Cd and Pb range from 0.04 to 0.13 μg/L. Recoveries of the added standards are in the range from 90% to 118%, and the precision is 1.2% to 4.8%. Operation of this method is simple and feasible for routine laboratory analysis. © 2016, Science Press. All right reserved.