IAQ: Direction of Airflow

At the outset of the SARS-CoV-2/COVID-19 outbreak in China, researchers identified an airconditioned five-story windowless restaurant common to ten cases of infection.

The study concluded the key factor for infection was the direction of the airflow. The researches also stated, “Virus transmission in this outbreak cannot be explained by droplet transmission alone.”

Ventilation, the lack thereof, was a factor, but the direction of airflow was the key factor.

Read the full report here: CDC, 7 July 2020 |  COVID-19 Outbreak Associated with Air Conditioning in Restaurant, Guangzhou, China, 2020

How is the direction of airflow important? If you, a non-smoker, have been on the receiving end of secondary smoke, you can imagine being on the receiving end, the downstream of an airborne pathogen.

In surgical rooms where open-heart surgery and like invasive procedures are carried out, HVAC designers arrange HVAC air distribution devices to create a one-pace route for conditioned air to pass over the patient.

This simple design tactic applied to other habitations can be a significant preventive against airborne pathogens.


Published by John White

A lifetime (over 50 years) of experiences with automation and control systems ranging from aerospace navigation, radar, and ordinance delivery systems to the world's first robotic drilling machine for the oil patch, to process-control systems, energy management systems and general problem-solving. At present, my focus is on self-funding HVAC retrofit projects and indoor air quality with a view to preventing infections from airborne pathogens.

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