The right defense starts with understanding your actual airborne pathogen dynamics 

Droplets that aerosolize and stay suspended in air for hours and travel significantly beyond six feet. ​

Delta Validation by Arise Diagnostics 

"The evidence suggests that mitigation airborne transmission should be at the forefront of our disease-control strategies for COVID-19" - Joseph Allen, Director of Healthy Buildings Program at Harvard TH Chan School of Public Health

In response to the airborne transmission risk, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) published a position document on infectious aerosols, stating the role of building operations and HVAC systems in infection control:
​“Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled. Changes in building operations, including the operation of heating, ventilating, and air conditioning systems, can reduce airborne exposures.”5