Joseph G. Allen, an Associate Professor and Director of the Healthy Building Program at Harvard’s TH Chan School of Public Health, believes that an indoor air quality revolution is on the horizon, which could be one of the most important public health victories of the 21st century. Two recent events have contributed to this moment. Firstly, the Centers for Disease Control and Prevention (CDC) announced new health-based ventilation targets on Friday, which could significantly improve indoor air quality. Secondly, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) issued enhanced ventilation standards to strengthen the CDC recommendations.
Although the importance of ventilation in combating the spread of COVID-19 has been debated, this is the first time a government agency has set ventilation targets to prevent respiratory infections. The CDC’s new goal is at least 5 air changes per hour (ACH), which is equivalent to all the air in a room being replaced five times within an hour. The previous lack of specific ventilation standards resulted in confusion and lack of accountability.
Since the 1970s, viruses such as influenza, respiratory syncytial virus (RSV), and other respiratory pathogens have affected people who spend most of their time indoors with minimal ventilation standards, including offices, nursing homes, meat processing plants, and prisons. This has highlighted the need for better ventilation standards beyond COVID-19, as poor ventilation is associated with “sick building syndrome,” including headaches, poor concentration, and increased absenteeism.
The CDC has also recommended increasing the minimum filtration rate by using higher quality MERV-13 filters, which can capture particles from outdoor air pollution and improve energy efficiency by making regular adjustments to buildings. ASHRAE’s response to the CDC’s recommendations shows that the industry group has recognised the need for a course correction, particularly in schools, offices, and homes.
Although ASHRAE’s proposed standard does not go far enough and is unlikely to be incorporated into building codes, it is still a monumental change that raises the lower limits for minimum indoor clean air standards. Not only does this rectify a decades-old mistake, but it also provides hope for public health advocates who have been pushing for this change for years. It is time to breathe a sigh of relief.