Potential Connection Between Air Quality And COVID-19 Cause for Concern for AC Planners
Monday 28 June 2021
Professor Cath Noakes of the University of Leeds’s School of Civil Engineering in the UK suggests that using AC systems during the coronavirus pandemic should be considered one aspect of a wider holistic approach to indoor air quality. Noakes argues the importance of air movement and human behavior as contributing factors towards the spread of coronavirus.
Professor Noakes says that emerging evidence over the potential for COVID-19 to spread through the air as well as water droplets means that AC planners should exercise more caution when planning air movement systems in small buildings and other enclosed spaces.
The risk of coronavirus spreading in well-ventilated spaces, even small spaces, is relatively low. However, there is concern that the virus could spread in poorly ventilated areas. The longer someone spends in such an area, the increased chances of the virus spreading.
These comments were made during a recent BESA webinar. The webinar focused on the importance of air quality and ventilation in managing COVID-19 transmission between people. One of Professor Noakes main arguments was the importance of considering how people interact with ventilation systems and other HVAC units. She argued that there was little point in saying that a system can deliver if people keep windows closed or turn off the system when they need to. This is a good first step, but people must know why they should use their ventilation effectively. Knowing how isn’t enough to convince people to do it. Noakes argues taking the same approach to air conditioning and purification technologies, in particular because of how these systems are used alongside other systems in the same buildings.
Since the pandemic began, HVAC experts have argued for building operators and FM specialists to ensure that buildings have enough ventilation to ensure a consistent flow of clean air into a building to prevent COVID-19 outbreaks. The industry has also advocated to ensure that systems in place don’t simply recirculate air and potentially expose people to the same infected air.
Professor Noakes says the advice is more important than ever as most cases of airborne transmission that had been recorded since the pandemic began occurred in enclosed spaces with reduced ventilation rates. Ventilation rates of between one and three liters per second per person were the most problematic. There’s almost no evidence suggesting that airborne transmission is happening in areas with ten liters per second per person.
Even so, Noakes advocates treating each case individually as the rates of aerosol transmission can vary between people. One must factor in the nature of the building and the people inside the building when estimating the most efficient air conditioning rates.
Concerns about how ventilation systems are used to manage contaminants and pollutants within enclosed spaces will likely become a more long-term issue for the HVAC sector. These concerns are likely to continue past the current pandemic and into the near future.
Trade bodies warn of shifts in public perception about air quality and supply in public and private spaces will alter how HVAC manufacturers and providers will operate in the future.