Dual-size nanofibers consisting of a random mixture of nano- and submicron-size nanofibers are promising structures for specific applications such as air filters because of their increased specific surface area and low pressure drop. Synthesis of dual-size nanofibers using one-step electrospinning was reported here for the first time. The formation of well-mixed nano- and submicron-size cellulose-polyvinylpyrrolidone nanofiber composites was accomplished utilizing the physical properties of TEMPO-oxidized cellulose nanofibers (i.e., high thixotropy and high magnitude of zeta potential) and tuning the charge of the polymer jet, which influences the formation and shape of Taylor cone, and Coulombic explosion. The dual-size nanofibers were then spun on the surface of a HEPA filter to obtain a multilayer air filter. Aerosol filtration measurements show that this multilayer air filter has an incredibly high performance, shown by the high quality factor (Qf), 0.117 Pa, which is 10 times the Qf of commercial HEPA filters.
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http://dx.doi.org/10.1021/acs.langmuir.7b01193 | DOI Listing |
Health Phys
January 2025
National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, 100088, China.
Inhalation of 131I is the main route for internal doses to nuclear medicine workers. This study aimed to establish a simple analysis method for determining 131I activity in carbon cartridges, explore the activity concentration of 131I in nuclear medicine departments, and evaluate the internal dose of workers. A total of 21 nuclear medicine departments in the hospital conducted air sampling using a high-volume air sampler equipped with carbon cartridges and glass fiber filters to collect gaseous 131I and aerosol 131I, respectively.
View Article and Find Full Text PDFEClinicalMedicine
January 2025
WEISS Centre, University College London, UK.
Background: The COVID-19 pandemic highlighted the need for improved infectious aerosol concentrations through interventions that reduce the transmission of airborne infections. The aims of this review were to map the existing literature on interventions used to improve infectious aerosol concentrations in hospitals and understand challenges in their implementation.
Methods: We reviewed peer-reviewed articles identified on three databases, MEDLINE, Web of Science, and the Cochrane Library from inception to July 2024.
J Expo Sci Environ Epidemiol
January 2025
Department of Environmental and Occupational Health, Joe C. Wen School of Population & Public Health, University of California, Irvine, CA, USA.
Background: Children living in communities with lower socioeconomic status and higher minority populations are often disproportionately exposed to particulate matter (PM) compared to children living in other communities.
Objective: We assessed whether adding HEPA filter air cleaners to classrooms with existing HVAC systems reduces indoor air pollution exposure.
Methods: From July 2022 to June 2023, using a block randomized crossover trial of 17 Los Angeles Unified School District elementary schools, classroom PM concentrations were monitored and compared for 99 classrooms with HEPA filter air cleaners and 87 classrooms with non-HEPA filter air cleaners.
Sci Total Environ
January 2025
Particle Pollution Research and Management Center, Incheon 21999, Republic of Korea; Department of Environmental Engineering, Inha University, Incheon 22212, Republic of Korea. Electronic address:
The current definition of primary particulate matter (PM) encompasses filterable PM (FPM) and condensable PM (CPM), which are evaluated using two distinct conventional measurement methods: cooling and dilution. While the cooling method exclusively considers the homogenous formation of CPM, the dilution method, closer to real-world conditions, neglects FPM characterization. To overcome this limitation, we propose a doubled-dilution system that enables the parallel characterization of both FPM and primary PM without diverting FPM from the CPM formation pathway.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, PR China.
Vehicle nitrogen oxides (NO) significantly increase nitrogen dioxide (NO) exposure in traffic-related environments. The NO/NO ratios are crucial for accurate NO modeling and are closely linked to public health concerns. In 2020, we used a mobile platform to follow test trucks (plume-chasing) that were installed with a portable emission measuring system (PEMS) on two restricted driving tracts.
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