Date: 2020-10-01 15:09:00

Note: This article appears in the 2020 edition of AMCA inmotion magazine.


Are heating, ventilating, and air-conditioning (HVAC) systems “spreaders” of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19)? That possibility became acute in July when 239 scientists from 32 countries co-signed an appeal to the medical community and relevant national and international bodies to recognize the potential for transmission of SARS-CoV-2—initially thought to be spread primarily through large respiratory droplets that, once expelled, fall quickly to the floor—as an aerosol.

“Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 m [3 to 6 ft] from an infected individual,” the commentary1 reads.

ASHRAE assumed a leadership role in helping the buildings industry respond to COVID-19 threats by establishing the ASHRAE Epidemic Task Force. The task force reviews, organizes, consolidates, and publishes information about the spread and mitigation of COVID-19 and other infectious diseases.

Among the task force’s recommendations are providing sufficient and effective ventilation (supplying clean outdoor air, minimizing recirculation of air) and supplementing general ventilation with such airborne-infection controls as local exhaust, high-efficiency air filtration, and germicidal ultraviolet—or, as it commonly is known, “UV-C”—light.

UV-C fixtures can be installed in air-handling units and in the upper part of indoor spaces to inactivate airborne infectious agents. Although the technology is covered in ASHRAE Handbook volumes and other technical resources, as evidenced by several recent webinars AMCA has participated in, questions concerning its application persist. In response, we made the use of UV-C light for HVAC air and surface disinfection the subject of this year’s cover story. Long-established but not widely utilized, UV-C light has proven effective against previous coronaviruses and looks promising against SARS-CoV-2.

As always, our mission with AMCA inmotion is to advance the knowledge of air systems. Toward that end, we have prepared articles on mitigating system effect, modifying life-safety dampers in the field, interpreting fan curves, and specifying high-temperature fans.

I hope you find this edition of AMCA inmotion useful. If there is a topic you would like to see covered in a future issue, please contact me at [email protected] or +1 847-704-6335.


  1. Morawska, L., & Milton, D.K. (2020). It is time to address airborne transmission of COVID-19. Retrieved from

Scott Arnold is manager of industry content for AMCA International and editor in chief of AMCA inmotion.