COUNTERFOG® has been proposed as a rapid decontamination and disinfection technology that uses dynamic submicrometric-disinfecting fog cones. When projected onto surfaces, they create a micrometre-thick film of disinfectant minimizing the use of liquids and the impact on environment. The extremely thin film is intended to be enough to cover and kill microorganisms and simultaneously thin enough to evaporate in a few minutes-depending on the environmental conditions. In the present work, experimental tests were carried out to verify this hypothesis. These include a physical characterization of the fog in the cone, a measurement of the liquid flow projected on surfaces as well as disinfection tests with a series of microorganisms. In addition to these results, operational recommendations are derived to ensure disinfection reliability.

The COVID-19 pandemic highlighted the dangers of airborne pathogen transmission. SARS-CoV-2 is known to be transmitted through aerosols; however, little is known about the dynamics of these aerosols in real environments, the conditions, and the minimum viral load required for infection. Efficiently measuring and capturing pathogens present in the air would help to understand the infection process. Air samplers usually take several hours to obtain an air sample. In this work a fast (1–2 min) method for capturing bioaerosols into a liquid medium has been tested in hospital rooms with COVID-19 patients. This fast sampling allows detecting transient levels of aerosols in the air. SARS-CoV-2 RNA is detected in aerosols from several hospital rooms at different levels. Interestingly, there are sudden boosts of the SARS-CoV-2 load in the air, suggesting that SARS-CoV-2 could be released abundantly at certain moments. These results show that the distribution of SARS-CoV-2-containing aerosols is not homogeneous in the hospital room. This technology is a fast and effective tool for capturing airborne matter in a very short time, which allows for fast decision-making any kind of hazard in the air is detected. It is also useful for a better understanding of aerosols dynamics.