Résumé
In this paper we report two applications of a subcategory of air cleaning devices based on soft ionization that do not cause molecular fragmentation. A system that includes two unipolar ionizing modules has been used to simultaneously produce positive and negative ions in the air. In one set of experiments a large chamber (28 m3) was used to study the effect of ions on reducing PM1.0 particles produced by a research grade calibrated cigarette. The data presented in this paper were obtained using a carbon-brush-based bipolar ionizer and a MERV 10 filter with electret media in a recirculating HVAC system. Significant improvement in removal rate of fine and ultrafine particles was achieved when using the bipolar ionizer in conjunction with the MERV 10 filter. The second set of experiments were conducted using a 36 m3 chamber, following BSL-3 standards, to study the effect of ions on aerosolized SARS-CoV-2. Results of these investigations reveal the inactivation rate of SARS-CoV-2 are enhanced when ions are introduced in the air;inactivation rates were increased by more than 60%and 90%for ion densities of 10,000/cc and 18,000/cc. IEEE
Résumé
The COVID-19 pandemic has highlighted the importance of indoor air quality (IAQ) since SARS-CoV-2 may be transmitted through virus-laden aerosols in poorly ventilated spaces. Multiple air cleaning technologies have been developed to mitigate airborne transmission risk and improve IAQ. In-duct bipolar ionization technology is an air cleaning technology that can generate ions for inactivating airborne pathogens and increasing particle deposition and removal while without significant byproducts generated. Many commercial in-duct ionization systems have been developed but their practical performance on pollutant removal and potential formation of byproducts have not been investigated comprehensively. The results in this study showed that the in-duct bipolar ionization technology can significantly improve the particle removal efficiency of the regular filter, while no significant ozone and ion were released to the indoor air. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.
Résumé
Ozone is a highly effective and broad-spectrum non-residual gas disinfectant.The global COVID-19 pandemic has significantly affected public safety and health, and low concentrations of ozone can inactivate the novel coronavirus.The negative ion generator is a safe and efficient method to generate ozone.Through corona discharge on the needle plate, an ion current can be formed between the needle-plate electrodes and a certain concentration of ozone can be released.In the research on the relationship between the electrode-to-plate distance and ozone release in the negative ion generator, different experimental observations show contradictory results, making the theoretical explanation very difficult and complicated.As the needle-to-plate electrode distance increases, the continuous exponential decreasing trend of ozone emission rate changes to a non-continuous step-wised decreasing pattern, which is defined as the Quantum Ozone Emission Effect (QOEE).The QOEE was observed in all negative ion generators when the plate material was aluminium, stainless steel, yellow brass, or copper.The observed quantum ozone emission effect in negative ion generators may be related to the gas ionization potential of the oxygen molecule and to the electron avalanche theory.The quantum effect of ozone emission is a manifestation of the quantum behavior of the microscopic electron world in the macroscopic world.The ozone emission quantum effect provides a novel technical method for measuring the microscopic properties and corona discharge characteristics of materials. © 2022, Editorial Department of Journal of Xidian University. All right reserved.
Résumé
Ionization spectra of substances are extensively used in their label free detection. Here we demonstrate the possibility of using plasma ionization to detect airborne and saliva SARS-COV-2 viruses through their emission spectra. It consists of an ionization chamber monitored by a fiber-optic UV-VIS spectrometer. The technique is completely label-free and can be programmed in real-time to detect different viral particles through their ionization emission spectra. Its average sensitivity for detecting deoxyribonucleic acid (DNA) bases in water is 20%/g in 1 mL of water. Its selectivity for DNA bases is through their relative emission peaks for adenine at 439.5 nm, cytosine at 440, thymine at 440.5, and guanine at 421.5 nm. The emission spectra of different electrode materials were also obtained to account for their contributions to the emission spectra of analytes. Gold electrodes were used owing to their resistance to corrosion and very low reaction with ionized species. The technique has the potential to be used in the point-of-care diagnostic and testing applications. IEEE