Development of respirator design for children using bamboo-based activated carbon filter and bipolar ionization

This paper proposes a respirator for children integrated with bamboo-based activated carbon filters and bipolar ionization as the sterilizer to increase protection from Covid-19 and other pathogens. The respirator, named as Bion-Kids, was designed based on the children's head-and-face anthropometry from direct measurement. The duration of sterilization process is controlled based on the activities, which are classified using the Recurrent Neural Network (RNN) model with dataset acquired from the accelerometer. Manufacturing process of the main body prototype comprises heat bending and 3D printing. The bamboo-based activated carbon filter was synthesized by applying heat and pressure at the strewed activated carbon particles on the N95 filter. Observation using scanning electron microscope showed the ability of the bamboo-based activated carbon filter to adsorb and trap the particles. Result of the qualitative fit test and questionnaire survey indicated that Bion-Kids is suitable and comfortable for the children's face. The result of filtration and bipolar ionization sterilization system analysis have also met the ISO14698 standard by not showing any infiltration of microorganisms on the blood agar media. This device may become an early-stage personal protective equipment against the transmission of Covid-19 and other pathogens. © 2022 THE AUTHORS

Large-scale evaluation of microorganism inactivation by bipolar ionization and photocatalytic devices.

The COVID-19 pandemic has raised awareness in the spread of disease via airborne transmission. As a result, there has been increasing interest in technologies that claim to reduce concentrations of airborne pathogens in indoor environments. The efficacy of many of these emerging technologies is not fully understood, and the testing that has been done is often conducted at a small scale and not representative of applied settings. There is currently no standard test method for evaluating air treatment technologies, making it difficult to compare results across studies or technology types. Here, a consistent testing approach in an operational-scale test chamber with a mock recirculating heating, ventilation, and air conditioning (HVAC) system was used to evaluate the efficacy of bipolar ionization and photocatalytic devices against the non-enveloped bacteriophage MS2 in the air and on surfaces. Statistically significant differences between replicate sets of technology tests and control tests (without technologies active) are apparent after 1 h, ranging to a maximum of 0.88 log10 reduction for the bipolar ionization tests and 1.8 log10 reduction for the photocatalytic device tests. It should be noted that ozone concentrations were elevated above background concentrations in the test chamber during the photocatalytic device testing. No significant differences were observed between control and technology tests in terms of the amount of MS2 deposited or inactivated on surfaces during testing. A standardized, large-scale testing approach, with replicate testing and time-matched control conditions, is necessary for contextualizing laboratory efficacy results, translating them to real-world conditions, and for facilitating technology comparisons.

Development of respirator design for children using bamboo-based activated carbon filter and bipolar ionization

This paper proposes a respirator for children integrated with bamboo-based activated carbon filters and bipolar ionization as the sterilizer to increase protection from Covid-19 and other pathogens. The respirator, named as Bion-Kids, was designed based on the children's head-and-face anthropometry from direct measurement. The duration of sterilization process is controlled based on the activities, which are classified using the Recurrent Neural Network (RNN) model with dataset acquired from the accelerometer. Manufacturing process of the main body prototype comprises heat bending and 3D printing. The bamboo-based activated carbon filter was synthesized by applying heat and pressure at the strewed activated carbon particles on the N95 filter. Observation using scanning electron microscope showed the ability of the bamboo-based activated carbon filter to adsorb and trap the particles. Result of the qualitative fit test and questionnaire survey indicated that Bion-Kids is suitable and comfortable for the children's face. The result of filtration and bipolar ionization sterilization system analysis have also met the ISO14698 standard by not showing any infiltration of microorganisms on the blood agar media. This device may become an early-stage personal protective equipment against the transmission of Covid-19 and other pathogens.

Evaluation of a bipolar ionization device in inactivation of antimicrobial-resistant bacteria, yeast, Aspergillus spp. and human coronavirus.

BACKGROUND: The efficacy of bipolar ionization in the healthcare setting has yet to be proven. A major limitation of studies sponsored by industry has been the assessment of efficiency within test chambers in which ozone levels are not adequately controlled. AIM: To assess the effectiveness of bipolar ionization against antimicrobial-resistant bacteria, fungi and human coronavirus within a controlled test chamber designed to mitigate the effect of ozone. METHODS: Bacteria- and fungi-inoculated gauze pads, and human coronavirus 229E-inoculated stainless steel plates were placed within the vicinity of the AIO-2 bipolar ionizer and left at room temperature (2 h for coronavirus and 4 h for bacteria and fungi). FINDINGS: Four hours of exposure to bipolar ionization showed a 1.23-4.76 log reduction, corresponding to a 94.2->99.9% colony-forming units/gauze reduction, in Clostridioides difficile, Klebsiella pneumoniae carbapenemase-producing K. pneumoniae, meticillin-resistant Staphylococcus aureus and multi-drug-resistant S. aureus. A 1.2 log 50% tissue culture infectious dose reduction in human coronavirus was observed after 2 h. CONCLUSION: The assessment of bipolar ionization systems merits further investigation as an infection control measure.

Unintended Consequences of Air Cleaning Chemistry.

Amplified interest in maintaining clean indoor air associated with the airborne transmission risks of SARS-CoV-2 have led to an expansion in the market for commercially available air cleaning systems. While the optimal way to mitigate indoor air pollutants or contaminants is to control (remove) the source, air cleaners are a tool for use when absolute source control is not possible. Interventions for indoor air quality management include physical removal of pollutants through ventilation or collection on filters and sorbent materials, along with chemically reactive processes that transform pollutants or seek to deactivate biological entities. This perspective intends to highlight the perhaps unintended consequences of various air cleaning approaches via indoor air chemistry. Introduction of new chemical agents or reactive processes can initiate complex chemistry that results in the release of reactive intermediates and/or byproducts into the indoor environment. Since air cleaning systems are often continuously running to maximize their effectiveness and most people spend a vast majority of their time indoors, human exposure to both primary and secondary products from air cleaners may represent significant exposure risk. This Perspective highlights the need for further study of chemically reactive air cleaning and disinfection methods before broader adoption.