Performance of in-duct bipolar ionization devices on pollutant removal and potential byproduct formation in indoor environments

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.

Quantum ozone emission effect in needle-to-plate negative ion generators

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.