Chlorine dioxide has become a widely used disinfectant during the COVID-19 pandemic. Even at very low concentrations, it is a fast-acting broad-spectrum surface

****!!!!****!!!!**** [Might UV light be shined in an area after a fumigation to help decrease the concentration of chlorine dioxide (generally in combination with aeration)? Perhaps even when performing airborne applications of chlorine dioxide at very low levels, a substantial amount of UV light be shined at various intervals to significantly reduce or eliminate existing ClO2 in air to provide confidence that concentration is not being inadvertantly built up beyond desired and safe concentration levels??? ]

****!!!!****!!!!**** "Room Shocker 30 Day Time-Release will inhibit the growth and or prevent any new bacteria, mold, mildew, fungus, spoors and any dangers pathogens from developing while maintaining the air quality at toxic free optimum level delivering a clean and odor free environment. Unlike our Quick-Release products the Time-Release products allow you to stay safely and comfortably in the room while the product is working."

{Nanomist} The present invention is an improved method for decontamination of a space and an integrated device that completes the decontamination cycle extremely fast while still being compact, lightweight, simple to operate and easy to move as a single unit. The method of the present invention delivers less biocide than is used in prior art methods at a very high rate of flux, allows the biocide to reside in the space being decontaminated to achieve a predetermined kill level, and then aerates the space. Because a nominal amount of biocide is used, there is less biocide to remove from the space than in prior art methods thereby reducing the time required for aeration and shortening the downtime for safe entry of the facility.

****!!!!**** "Although the ClO2 decontamination process utilizes a commercially-available ClO2 generation technology (i.e., Selectrocide® micro-reactors) the fumigant application method is in early stages of development and requires further testing and optimization"

****!!!!****!!!! {Abstract} "At extremely low concentrations (about 30 parts per billion), chlorine dioxide (ClO2) gas can inactivate airborne microbes and prevent respiratory disease. It has no toxic effect on animals at this level. However, the temperature dependence of the gas analyzer was found. Therefore, ***data correction is required for each temperature at which gas concentration is measured***. A theoretical analysis of the gas concentrations predicted by the rate of ClO2 gas released from the ClO2 generator was also performed."

****!!!!****!!!!**** "Decontamination of Category A Viruses on Porous Surfaces and Sensitive Equipment: ...The prototype will ultimately be evaluated in accordance with an EPA-approved protocol entitled “Efficacy of a Disinfectant Applied to a Room Via a Fogger or Misting Device” against a panel of organisms. The results will be submitted to the EPA to register the technology as a room disinfection device and claim “hospital and broad-spectrum” and “virucide” efficacy." "METSS is currently conducting a Phase II SBIR project for the EPA to develop a safe, robust, rapid, and effective chlorine dioxide (ClO2) gas dispersion system to be used for on-site room decontamination in hospital and non-hospital settings. This technology will meet the demands of the health care market to decontaminate porous materials and sensitive equipment in rooms or vehicles used for patient care or transport. This need was evident during the care and treatment of Ebola patients in the United States several years ago. At that time, it was clear that many facilities did not have the means to properly disinfect large items, like furniture, on-site; therefore, the items required transport off-site for proper treatment and disposal; a process that has inherent safety risks and associated costs. The ability to decontaminate a room containing porous materials and sensitive equipment on-site and in a non-destructive manner would be invaluable to the health care industry and meet a critical need for low-cost, simple solutions to decontaminate non-medical spaces as well. Based on feedback from potential end-users and results of development testing conducted during the first year of the project, a functional prototype is currently being designed, constructed, and tested. The prototype will ultimately be evaluated in accordance with an EPA-approved protocol entitled “Efficacy of a Disinfectant Applied to a Room Via a Fogger or Misting Device” against a panel of organisms. The results will be submitted to the EPA to register the technology as a room disinfection device and claim “hospital and broad-spectrum” and “virucide” efficacy."

****!!!!****!!!!**** "Gas chlorine dioxide has broad application prospects in the field of space disinfection, but the immaturity of its concentration online detection technology has greatly limited its promotion and application. "" USing LED as the light source, this paper designed a simplified single-wavelength dual-optical path differential absorption concentration detection probe, developed a gas chlorine dioxide concentration sensor that can detect the concentration range of 0~9 mg/L online, and takes a variety of measures to avoid photodegradation of gas chlorine dioxide during the detection process, and improve the life and stability of the sensor." "accuracy of the gas chlorine dioxide concentration sensor designed in this paper is better than that of 2% F.S., which can meet the needs of concentration detection for the spatial disinfection of chlorine dioxide."

****!!!!****!!!!**** "library reading room, when the concentration of gas chlorine dioxide is 0.3mg/m3, the sterilization time is 60min, and the sterilization time period is 20:00~21:00, the sterilization rate of gas chlorine dioxide reaches 99.23%... people can work and live normally, and it is harmless to the human body" "hospital wards, when the concentration of gas chlorine dioxide is 0.3mg/m3, the sterilization time is 60min, and the sterilization time period is 20:00~21:00, the sterilization rate reaches 99.63%"

"There are three main preventive measures for airborne infectious diseases, one is to find and eliminate the source of infectious diseases; The second is to use vaccines or increase immunity to resist the invasion of infectious diseases; The third is to block or eliminate the transmission route of infectious diseases. Since severe acute respiratory syndrome (Severe Acute Respiratory Syndrome) related pathogenesis and vaccines have not yet made breakthrough progress, the main way to prevent the spread of this malignant infectious disease is to block its effective transmission route, and air sterilization is one of the more effective means."

****!!!!****!!!!**** (2020). [It seems that light source was solely sunlight through glass window] "The illuminance was adjusted by opening or closing the curtain in the office"

"supplying chlorine dioxide gas into a space where floating virus can be present by a gas concentration which allows the animal to live or stay, but deactivates the virus."

"The emergent human coronavirus SARS-CoV-2 and its high infectivity rate has highlighted the strong need for new disinfection systems. Evidence has proven that airborne transmission is an important route of spreading for this virus."

****!!!!**** "We demonstrated here that ClO[2] gas is easily generated by mixing 3.35% sodium chlorite solution (Purogene) and 85% phosphoric acid at a 10:1 volume ratio..." "Under high-humidity (approximately 80% relative humidity), colony formation of both Staphylococcus aureus and Escherichia coli was completely inhibited by ClO2 gas exposure at 1.0 ml/m3 sodium chlorite solution (mean maximal concentration of 3.0 ppm). Exposure at 4.0 ml/m3 sodium chlorite solution (mean maximal concentration of 10.6 ppm) achieved complete inactivation of Bacillus atrophaeus spores. In contrast, without humidification, the efficacy of ClO2 gas was apparently attenuated, suggesting that the atmospheric moisture is indispensable. Delicate electronic devices (computer, camera, etc.) operated normally, even after being subjected to more than 20 times of fumigation."

****!!!!****!!!!*** "One of Raytec's patents covers the use of dry-media chlorine dioxide in air filtration systems. These systems use a multi-stage oxidizing process, which allows for the decontamination of air and the discharge of clean air without residual chemicals. Raytec has built and tested several of these filters,which can be used as a continuous treatment process in buildings, homes, malls, airplanes and any other environments where indoor air quality is of concern." "The main application for Raytec's tea bag technology is as a wash to sanitize produce and other products suspected to be contaminated with bacteria of any kind."

****!!!!****!!!*** "A single ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 65% and 30%, respectively. By contrast, a twice-daily ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 74% and 38%, respectively. The statistical analysis results showed that the residual bacterial concentration level was determined primarily by the number of individuals present in the cafeteria, the temperature, and the ClO2 concentration, whereas the residual fungal concentration level was determined mainly by the temperature, the total number of suspended particles, and the ClO2 concentration."

****!!!!****!!!!*** {Original paper at https://www.jstage.jst.go.jp/article/yakushi/127/4/127_4_773/_pdf} "The efficacy of chlorine dioxide (ClO2) gas at very low concentrations for hyphal growth of Alternaria alternata related to fungal allergy was evaluated... ClO2 gas (average 0.075 ppm, 0.21mg/l) inhibited hyphal growth of the fungus, but not germination of fungal spores. The hyphal length was more than 1780mm under air conditions(control)and 49±17mm unde rClO2 gas conditions for 72 h. According to the international chemical safety card, threshold limit values for ClO2 gas are 0.1 ppm as an 8-h time-weight average and 0.3 ppm as a 15 min short-term exposure limit. From these data, we propose that treatment with ClO2 gas at very low concentrations in space is a useful tool for the growth inhibition of fungi in the fields of food, medicine,etc. without adverse eŠects"

"Sanitary and hygienic studies were carried out to assess the real danger of finely dispersed chlorine dioxide aerosols when processing air in rooms for personnel of medical organizations. High concentrations of chlorine dioxide are retained in the air during exposure and removed after ventilation. Evaluation of the safety of the use of three "sachets", which, upon activation, emit chlorine dioxide in the form of vapor, was carried out on white rats, taking into account various toxicity indicators. Recommended for use in the adult population."

***** {Calculation methods for air concentrations of gas in ppm"the OSHA PEL in mg/m3 is absolutely fixed and not subject to corrections for temperature and pressure." "This constraint implies that volume concentration of gases in parts per million (ppm) must be with reference to some defined temperature and pressure; these are NTP (25 °C and 760 mm Hg) in the OSHA PEL limit."

*** {Includes excellent basic info on chlorine dioxide}

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"Computational fluid dynamics (CFD) computed results are presented with streamlines and vector plots to observe the flow conditions inside the package. "

Concentration of a pollution in a limited space as a room depends on the amount of polluted material spread in the room, supply of fresh air, outlets positions and construction, principles used for supply and outlet from the space

When measuring gases like carbon dioxide, oxygen, or methane, the term concentration is used to describe the amount of gas by volume in the air. The 2 most common units of measurement are parts-per

*****!!!!****!!!!*** {Provides excellent definitions of ppm in air vs. liquid, etc} [Helpful note: Molecular weight of Chlorine Dioxide is 67.45] The unit of gas concentration is converted into another unit.

******!!!!!******** "Organic films are probably common on atmospheric aerosol particles and that they may occur under certain circumstances on fog droplets, cloud droplets, and snowflakes. If present, they will increase the lifetimes of aerosol particles, fog droplets, and cloud droplets, both by inhibiting water vapor evaporation and by reducing the efficiency with which these atmospheric components are scavenged. The presence of the films will not cause a significant reduction of solar radiation within the aqueous solution. It appears likely, however, that the transport of gaseous molecules into and out of the aqueous solution will be impeded by factors of several hundred or more when organic films are present. Since incorporated gas molecules provide much of the oxidizing potential of atmospheric water droplets, the organic films will play a major role in droplet chemistry by strongly inhibiting solution oxidation."

****!!!!****!!! "The efficacy of chlorine dioxide (ClO(2)) gas at very low concentrations for hyphal growth of Alternaria alternata related to fungal allergy was evaluated using a fungus detector. The fungus detector is a plastic sheet with a drop of spore-suspending medium, and it makes possible clear observations of hyphal growth with a light microscope. ClO(2) gas (average 0.075 ppm, 0.21 microg/l) inhibited hyphal growth of the fungus, but not germination of fungal spores. The hyphal length was more than 1780 mum under air conditions (control) and 49+/-17 microm under ClO(2) gas conditions for 72 h. According to the international chemical safety card, threshold limit values for ClO(2) gas are 0.1 ppm as an 8-h time-weight average and 0.3 ppm as a 15 min short-term exposure limit. From these data, we propose that treatment with ClO(2) gas at very low concentrations in space is a useful tool for the growth inhibition of fungi in the fields of food, medicine, etc. without adverse effects."

*********** (2020) {Use of low levels of chlorine dioxide in air as disinfectant in hospital laundry and dishwashing rooms}