A new method is presented for calculating a building-specific subslab to indoor air attenuation factor for use in assessing subsurface vapor intrusion to indoor air. The technique includes (1) subslab gas extraction with flow and vacuum measurements and mathematical modeling to characterize the bulk average vertical gas conductivity of the floor slab, (2) monitoring of the ambient pressure gradient across the floor slab with a micromanometer, (3) calculating the volumetric flow of soil gas into the building ( Q), and (4) dividing Q by the building ventilation rate ( Q) to calculate a building-specific attenuation factor. Sample calculations using order statistics from 121 individual tests are comparable to the U.S. Environmental Protection Agency empirical attenuation factors for residential buildings and the U.S. Navy empirical attenuation factors for commercial/industrial buildings. A case study of a commercial building shows encouraging agreement between the attenuation factors calculated via this method and via conventional subslab and indoor air sampling.
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http://dx.doi.org/10.1021/acs.est.8b01106 | DOI Listing |
Sci Rep
January 2025
Innovation Institute for Sustainable Maritime Architecture Research and Technology, Qingdao University of Technology, Qingdao, 266033, People's Republic of China.
During the hot summer months, the significant temperature disparity between outdoor and indoor air-conditioned spaces can lead to thermal discomfort and pose a potential health risk. Transition areas such as corridors and elevator lobbies, serving as intermediary zones connecting indoors and outdoors, have been found effective in mitigating this thermal discomfort. In this study, three different temperatures (25 °C-case 1, 27 °C-case 2, and 29 °C-case 3) were employed to investigate the dynamic physiological regulation and thermal perception response of individuals when transitioning from an outdoor environment into an indoor neutral room through a transition space.
View Article and Find Full Text PDFBMJ Open
January 2025
School of Nursing, Haramaya University College of Health and Medical Sciences, Harar, Ethiopia.
Introduction: Although evidence exists on the impact of microbiota on pregnancy outcomes in many high-resource settings, there is a lack of research in many low-resource settings like Ethiopia. This study aims to fill this gap by studying the gut and vaginal microbiota changes throughout pregnancy and assess how these changes relate to pregnancy outcomes among a cohort of pregnant women in eastern Ethiopia.
Methods And Analysis: Vaginal and stool samples will be collected using DNA/RNA Shield Collection kits three times starting at 12-22 weeks, 28-36 weeks and at birth (within 7 days).
Environ Pollut
January 2025
State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan province, China. Electronic address:
Dental operations inherently involve a high risk of airborne cross-infection among medical staff and patients due to the exposure of respiratory secretions, which contain pathogenic microorganisms and typically spread in the form of aerosols. In order to contribute to the understanding of aerosol dynamics during dental operation and efficiently mitigate their dispersion and deposition through appropriate ventilation, 3D numerical simulations and full-scale experimental measurements were performed in this study. The indoor airflow distribution and dynamic aerosol behaviors observed under three optimized ventilation schemes (Scenario I-III) were compared with those observed under the current ventilation system.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America.
The SARS-CoV-2 virus caused the COVID-19 pandemic and brought major challenges to public health. It is transmitted via aerosols, droplets, and fomites. Among these, viral transmission through fomites is not well understood although it remains a very important transmission route.
View Article and Find Full Text PDFJ Occup Environ Hyg
January 2025
R.E.M. Risk Consultants, Dallas, Texas.
In a two-story retail mall in the Southeastern United States, employees within Store A (located on the second level) began to feel headaches and general unease and discussed the symptoms among themselves. Approximately 1.5 hr later, an employee called 9-1-1.
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