ognizant Communication Corporation

TECHNOLOGY
A Journal of Science Serving Legislative, Regulatory, and Judicial Systems
Human Advancement · Environmental Protection  · Industrial Development
 

ABSTRACTS
Volume 9, Number 4

Technology, Vol. 9, pp. 173-185
1072-9240/04 $20.00 + 00.
Copyright © 2004 Cognizant Communication Corp.
Printed in the USA. All rights reserved.

The Development of Low Volatile Organic Compound Emission House: A Case Study

Hai Guo, Frank Murray, and Shun-Cheng Lee

Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong

An aim in developing a low volatile organic compound (VOC) emission house is to reduce the level of VOCs in domestic housing. In this article, a case study for the reduction of exposure to VOCs from a newly constructed residential house is presented. Our study indicates that VOCs are present in paints, adhesives, consumer products, carpets, and certain wood-based products. These VOCs are commonly found in indoor environments. A reduction of VOC exposure, by improved building design and material selection, would benefit the residents. The total VOC (TVOC) concentrations measured in the low VOC emission house range from nondetectable to 43 mg/m3. These values are much lower than the published values (0.48-31.7 mg/m3) for new houses in Scandinavian countries and in the US. The low TVOC concentrations obtained in this study probably result from the high ventilation rates in this low VOC emission house and the use of low VOC emission materials. This study summarizes that there are three ways to improve indoor air quality (IAQ). The most effective strategy for controlling IAQ is pollution prevention and the next most important is the design of ventilation rates to handle uncontrollable sources. Air cleaning is the third means of pollution control widely applied to VOCs generated by indoor sources.

Key words: Volatile organic compound; Emission; Indoor air quality; Modeling; Environmental chamber; Pollution prevention strategy; Ventilation; Ageing

Address correspondence to Hai Guo, Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Tel: (852) 27666017; Fax: (852) 23346389; E-mail: ceguohai@polyu.edu.hk




Technology, Vol. 9, pp. 187-194
1072-9240/04 $20.00 + 00.
Copyright © 2004 Cognizant Communication Corp.
Printed in the USA. All rights reserved.

Examination of Backfill Materials for High-Level Waste Repository

D. S. McKinney, M.-S. Yim, and D. Hesterberg

North Carolina State University, Raleigh, NC 27695

A popular material of choice for a backfill in a high-level waste (HLW) repository is bentonite. However, a concern has been expressed for the use of bentonite as backfill at the Yucca Mountain HLW repository due to the unsaturated nature of the site and the associated high-temperature conditions. In this article, the thermal and sorption properties of various minerals that might be used as backfill at Yucca Mountain were investigated. The minerals examined include bentonite, kaolinite, zeolite, apatite, calcite, and silica. Simulated thermal stability tests were performed on these materials to observe their individual dehydration properties. Batch sorption tests were conducted to examine the minerals' capacities to retard the migration of Sr2+, Am3+, Ra2+, TcO4-, and I- by using nonradioactive surrogate tracers. Results indicated that silica, calcite, and kaolinite could provide good thermal properties for the Yucca Mountain backfill. Results of sorption studies showed zeolite, calcite, and apatite as good cation sorbers. No mineral was found to be a good anion sorber. A combination of these minerals (silica, kaolinite, calcite, apatite, and zeolite) is desirable to provide an effective backfill. More investigation is needed to add a good anion sorber.

Key words: Waste repository; Backfill material; Temperature conditions; Sorption properties

Address correspondence to M.-S. Yim, North Carolina State University, Raleigh, NC 27695. Tel: (919) 515-1466; Fax: (919) 515-5115; E-mail: yim@ncsu.edu




Technology, Vol. 9, pp. 195-207
1072-9240/04 $20.00 + 00.
Copyright © 2004 Cognizant Communication Corp.
Printed in the USA. All rights reserved.

Importance of Waste Form-Specific Leach Modeling in Low-Level Waste Source Term Analysis

Man-Sung Yim1 and Sol-Il Su2

1North Carolina State University, Raleigh, NC 27695-7909
2Institute of Nuclear Energy Research, P.O. Box 3-14, Lung-tan, Taiwan 32500

The purpose of this study was to examine the importance of waste form-specific leach modeling in low-level radioactive waste (LLW) source term analysis. The tasks performed include: 1) detailed characterization of radionuclide inventory distributions in LLW to identify major waste forms and their leach characteristics, 2) development of a new source term computer model to support waste form-specific analysis, and 3) quantifying uncertainty due to the use of alternative modeling approaches for the major waste forms. The analyses were performed for 14C, 129I, 99Tc, 36Cl, 226Ra, 238U, and 239Pu. Results indicated that detailed waste form-specific modeling was not critical in reducing uncertainty in LLW source term analysis. Investigation of parameter uncertainty for the Kd values of nuclides, water infiltration rate, and the inventory in the surface-contaminated waste remains important to better characterize the uncertainty in LLW source term analysis.

Key words: Low-level waste; Leach modeling; Waste forms; Waste form-specific analysis

Address correspondence to M.-S. Yim, North Carolina State University, Raleigh, NC 27695. Tel: (919) 515-1466; Fax: (919) 515-5115; E-mail: yim@ncsu.edu




Technology, Vol. 9, pp. 209-218
1072-9240/04 $20.00 + 00.
Copyright © 2004 Cognizant Communication Corp.
Printed in the USA. All rights reserved.

An Epidemiological Study on Sick Building Syndrome in Winter in Shanghai

Chen Jigang, Xiang Cuiqin, Zhang Yunying, Zhang Minhua, Shen Hong, and Zhang Shengnian

Shanghai Institute of Preventive Medicine, 1380 Zhongshan Road West, Shanghai 200336, China

Sick building syndrome (SBS) was investigated in a population of 841 office employees who were working in 27 office buildings completed since 1986 in Shanghai. The work included evaluation of room conditions; environmental analyses; and assessment of subjects including application of a symptom questionnaire, medical examinations, and neurobehavioral evaluation system testing (NEST). The results showed an increased rate of several important symptoms of more than 25%, the rates of eye and throat irritate signs were more than 30%, and the average personal symptom index and five personal symptom index were 2.91 and 1.69, respectively. The results indicated the reported symptom rates could not be supported from the medical examinations and NEST. And sex differences in positive eye irritation signs were in conflict with those of eye symptom reporting, which was also opposite to the results of the previous study. It suggested that more attention should be paid to the objective signs in an epidemiological study of SBS. The results demonstrated that some general conditions of offices, such as smoking/nonsmoking, indoor planting, and decorating date, could affect the presentations of SBS.

Key words: Sick building syndrome; Symptom reporting; Medical examination; Neurobehavioral evaluation system testing

Address correspondence to Chen Jigang, Shanghai Institute of Preventive Medicine, 1380 Zhongshan Road West, Shanghai 200336, China.