Air Quality Statement from Mechanical Engineering Firm
Properly engineered, designed, installed and operated HVAC systems in and of themselves do not contribute to or stop the spread of air-borne diseases. Especially COVID-19.
The primary exposure of air-borne diseases is via the droplets of moisture that are expelled from an infected individual while talking, sneezing and/or coughing. These droplets are relatively large. They drop to the floor fast. That is how the 6' social distancing was developed. The wearing of masks reduces the distance these droplets can travel.
Discussion has been made with regard to better filtration in mechanical systems to prevent the spread of air-borne diseases. The return duct system of mechanical systems is not designed to capture these particles. The velocity of the air in the duct is not fast enough to draw in and keep the droplets moving all the way to the filters. Further dilution via proper outside air exchange will help. Regardless, Viruses will be passed between people in the room and not by the HVAC system.
The only systems that possibly could stop the spread of air-borne diseases are laboratory like clean room systems with proper air flow differentials and exhaust to isolate individuals who are contagious.
District 96 will ensure the HVAC systems are running, have the proper amount of outside air (for dilution), and have the proper/high quality filters.