SHIC-funded UMN project highlights aerosol technologies

A project designed to help prevent the spread of infectious bioaerosols capable of causing epidemics of swine disease with significant economic consequences is underway. Funded by the Swine Health Information Center (SHIC) and led by staff at the University of Minnesota (UMN), work on Goal 1 began in October 2021 and provided the first information. This part of the project identifies existing and emerging aerosol technologies and procedures, and then examines them to assess their ability to contain bioaerosols in the face of outbreaks in pigs.

As part of the literature review conducted during the first objective, the researchers identified more than 80 references on different technologies. Those identified so far include fibrous filtration, ionization, bipolar ionization, type C ultraviolet light, type A ultraviolet light, electrostatic precipitation, microwaves, photoelectrochemical oxidation, plasmas non-thermal and air filters covered with materials with antimicrobial properties. Documentary research is carried out primarily through the Web of Science, PubMed, Google Scholar and Scopus databases. The researchers plan to finalize the review of the public database technologies by February.

Experts from the UMN College of Veterinary Medicine and the College of Science and Engineering were brought together to conduct an in-depth literature search on known technologies to remove airborne particles. Individuals have also been identified who have experience in managing outbreaks in the pig and poultry industries, managing outbreaks from a regulatory perspective, as well as others with experience in managing outbreaks. epidemics of human and animal diseases. An additional group that will assist in the selection and evaluation of technologies and measures for their application to pigs has also been identified with plans to continue the progress of the project in early 2022.

The distribution of references and a description of the most common technologies are as follows:

• Fibrous filtration (11 references): Filtration is the most well established and widely applied approach for biocontainment. Its method of action is to indiscriminately remove particles from air currents. There is a balance between particle size depending on the removal efficiency of a filter, which should be as high as possible, and the pressure drop across the filter for a given flow rate, which is directly related to costs. of the operation of the filter. In addition, the filter load increases the pressure drop but also the efficiency, and must be taken into account in the application of the filter.
• Ultraviolet Light Technologies (16 references): UV-C light at 254 nanometers (nm) is an established pathway to inactivating pathogens in aerosols and on surfaces, as nucleic acid molecules readily absorb them. photons close to this wavelength. UV-C (and potentially UV-A) sources can be incorporated into conduits to directly inactivate pathogens in aerosols, in conjunction with filters to inactivate collected pathogens, and in upper chamber bulbs to inactivate pathogens. larger spaces. However, these generally cannot operate continuously, as UV-C can be mutagenic or carcinogenic at sufficiently high exposure levels.
• Electrostatic Precipitation (10 references): Commonly used in the combustion industry, electrostatic precipitation is a process in which particles are unipolarly ionized by interaction with ions in the gas phase, and the ionized particles are exposed to fields continuous electrics, which leads to their deposition. Electrostatic precipitators (ESPs) are competitive technologies with filters, capable of achieving similar to better collection efficiencies with minimal pressure drops. They still require periodic cleaning of the particles from the deposition electrodes, and their performance changes over time as the particles settle.
• Other Ionization, Catalysis and Disinfection Technologies: In addition to the established technologies previously discussed, there are more recently developed ionization schemes (16 references), photocatalytic approaches (nine references) and disinfection technologies (13 references). ) which are still in the developmental stage. These should be 1) tested for efficacy at scales relevant to agricultural biocontainment and 2) tested for animal safety.

This work will be complementary to the additional objectives of the project which will be addressed in 2022.

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