I was reading through my email this morning and saw an article from ChainStoreAge.com making the case for running the AC to help slow the spread of COVID-19 in stores. The publication is a newletter for the retail industry and usually has some interesting articles. Upon reading it, I would agree with the conclusion, but they failed to mention a very important part of the equation. Namely, that all filters are not created equally. If you have a mesh filter that you can see though, a great deal of dust, pollen, and smaller things like germs and viruses can sail right through it. The article quotes ASHRAE which is the respected leader in indoor air quality standards and testing but does not go on to cite the proper filter types required to achieve the result of reduced spread of disease. The standards for filtration that ASHRAE has established are known as MERV (Minimum Efficiency Rating Value). The higher the MERV number, the better the filtration. The reality is that no filter can stop all viruses, but the more particulate that they remove from the air the more viruses are removed as well.
Another possible technology to assist in removing bacteria and viruses from HVAC sysems is UV light treatment of the return air. The efficacy of the light is different for different types of pathogens, but it does provide extra benefit per the EPA. The main takeaway for you to get from all of this technical stuff is that your AC can help reduce illness, but only if you use high MERV filters and change them often. Stay safe and I hope the info above helps you to make better decisions aboutyour businesses indoor air quality.