Eighty-five percent of survey participants say they referred to ASHRAE's IAQ guidance documents, when making changes. More than 70% said they used guidance from the Centers for Disease Control and Prevention (CDC) and nearly 60% said they referred to guidance from the state/local departments of public health or education. Other documents mentioned by respondents are from the U.S. Environmental Protection Agency, the American Institute of Architects, the U.S. Green Building Council, the World Health Organization and the Healthy Buildings Program at the Harvard T.H. Chan School of Public Health.

Too Many Guidance Materials

Some surveyed complained there were too many materials from too many sources that contained too many different pieces of advice. Many called for a single guide, jointly created by the various bodies, but there is no such effort planned. “We have not to my knowledge made an attempt to create” a document with input from the various groups, says Metzger.

Anisa Heming, director of the Center for Green Schools, concurs. She adds, “I believe the source of much of the confusion has come from shifting messages out of the CDC on building ventilation. CDC is not taking input from the community of practice.”

Other findings of the 28-page report relate to the funding of K-12 school education and infrastructure, which is “fundamentally inequitable, given its reliance on local wealth. The pandemic has only served to further entrench those inequities along racial and socioeconomic lines,” says the report.

The study contains responses to questions about protocols and operations plans implemented to mitigate the spread of COVID-19 that were gathered from 47 districts representing more than 4,000 schools serving over 2.5 million students in 24 states.

Overwhelmingly, comments from survey participants and interview respondents credited any success of IAQ efforts relating to the coronavirus response to prompt leadership, a cache of preexisting wealth in well-funded districts and/or past investments in infrastructure.

“School districts without funding to keep their buildings in good condition are in the worst position to manage air quality during this and future pandemics,” says Heming.

For those districts not well funded, she adds, there may be help from the federal government to upgrade heating ventilating and air-conditioning (HVAC) systems.

In December, the federal government approved $54 billion for K-12 schools in the Coronavirus Response and Relief Supplemental Appropriations Act, known as the December Relief Act. And the Biden administration has $122 billion for schools in the proposed American Rescue Plan Act. “Design professionals have a big role to play in educating the school systems in their areas that the money can be used for facilities,” Heming says. “Because there are so many allowable uses for those funds going to schools, it’s easy to miss all the opportunities,” she adds.

Six Major IAQ Strategies

The published guidance by the various groups converges on six major IAQ strategies: Increase fresh air through mechanical ventilation; Increase outdoor air supply through the HVAC system; Implement a flushing process between occupancy periods where the HVAC system runs for a pre-specified duration or until a target of clean air changes has been reached; Increase outdoor air through the use of operable windows; Open windows to increase the outdoor flow; Place fans in windows to exhaust room air to the outdoors; Remove airborne contaminants through filtration; Upgrade to filters with higher minimum efficiency reporting values (MERV) ratings, with MERV 13 or better as a target for removing airborne viral particles in recirculating systems (MERV ratings range from 1-16, with 16 being the most efficient filtration); Install air cleaners with high-efficiency particulate air (HEPA) filters.

The most frequently cited challenge to implementing protective IAQ measures at schools is existing physical plants not designed to support the various recommended strategies.  

School districts that have been able to act have leaned heavily on their mechanical systems, such as increasing air supply through HVAC systems or upgrading filters to implement protective air quality measures for students and teachers.

The installation of higher-grade MERV filters in at least some of the schools in the district significantly increased by 120% during the pandemic. Many school districts believed their mechanical ventilation systems were too old to be compatible with newer filters.

High cost and lack of availability of filters due to increased demand were also issues. Some schools told stories of being sold MERV filters that were mislabeled and ended up having lower than anticipated ratings. Others mentioned they had inadequate staffing for filter inspection and maintenance.

Over half of participants estimated that energy costs were either moderately more or a lot more. But 21% of participants estimated that their IAQ efforts had no impact on costs.

It’s long been widely accepted that “better IAQ means better results for students,” says Metzger. “The pandemic made it a bigger issue than in the past.”