Photo 195454747 © Iuliia Petrovskaia |
classroom windows

Clearing the air

June 1, 2021
Some maintenance strategies for improving indoor air quality in school buildings can’t be carried out because facilities are outdated.

Education institutions must address indoor air quality deficiencies in their facilities as they deal with heightened health and safety concerns brought on by the Covid-19 pandemic.

In too many of the nation’s school buildings, systems are outdated or not designed to carry out recommended strategies for improving indoor air quality (IAQ).

That’s the conclusion of a report released in April by the Center for Green Schools, “Preparation for the Pandemic: How Schools Implemented Air Quality Measures to Protect Occupants from Covid-19.”

"Increasing clean air circulation for our teachers and students is vital to promoting public health and is a key green building strategy for school buildings," says Anisa Heming, director of the Center for Green Schools.

The report, completed with technical support from the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), sought to determine how school districts were prioritizing and carrying out indoor air quality recommendations for ventilation and filtration to help reduce coronavirus transmission in school buildings. Participants represented 47 districts or independent schools—more than 4,000 schools and 2.5 million students in 24 states.

“Ensuring enhanced air ventilation and filtration through engineering controls provides a comprehensive, layered strategy to protect staff and students from exposure to Covid-19,” the report says. “…Yet, before the pandemic, less than half of school districts in the country had an IAQ management program.”

Six Steps

The report identifies six major strategies schools have adopted for improving IAQ:

  • Increase outdoor air supply through the building’s heating, ventilation and air conditioning (HVAC) system.
  • Carry out a flushing process between occupancy periods in which an HVAC system runs for a pre-specified duration or until a target of clean air changes has been reached.
  • Open windows to increase the outdoor flow.
  • Place fans in windows to exhaust room air to the outdoors.
  • Upgrade to filters with higher minimum efficiency reporting values (MERV); MERV 13 or better should be the target for removing airborne viral particles in recirculating systems.
  • Install air cleaners with high-efficiency particulate air (HEPA) filters.

The strategies identified most often by administrators as priorities were increasing the outdoor air supply through the HVAC system, and flushing rooms with fresh air before and after they were occupied; 89% of survey respondents said they prioritized increasing the outdoor air supply, and 79% said they prioritized the flushing strategy.

But administrators also said their efforts to carry out those improvements were hindered by deficiencies in their buildings.

“The number one cited barrier was that at least some of their school buildings were not designed to support (the strategies),” the report states. “Some buildings were so dated that there were no controls to automate….Others mentioned the lack of staff and personnel bandwidth to keep up with the breadth of (indoor air quality) work needed in their school districts.”

One survey participant said: “Our staff has been fully consumed with managing Covid protocols, e.g., social distancing, barriers, face masks, contact tracing, busing, cleaning…We do not have the bandwidth or expertise to deal with HVAC-related issues.”

Finer filtering

Employing better air filters to limit the spread of Covid-19 also has been a popular strategy among schools. The installation of higher-grade MERV filters in at least some of the schools in a district increased by 120% during the pandemic, the report says.

But again, some schools say that their efforts to upgrade their filters have been constrained by the outdated systems and equipment in their buildings.

“Many school districts believed that their existing mechanical systems were too old to be compatible with newer filters,” the report says. “Many were concerned that the additional static pressure needed to support the increasing filtration efficiency from either a MERV 8 or 11 to a MERV 13 would overwhelm the system.”

Some survey participants indicated that the general guidelines calling for the highest possible MERV filters made it difficult to manage the expectations of parents and staff.

“Parents and staff feel that [installing MERV 13] is required, yet most of our units are older and cannot support a MERV 13 filter,” a survey participant said. “so when we state we installed a higher-rated MERV 11 filter, they feel we have not met the industry standard.”

In addition, the high cost and lack of availability of filters (because of high demand) were cited as impediments.

Opening windows or using fans in windows and doors to increase exhaust were the least popular strategies employed by schools. In some areas, climate and weather conditions made this approach unfeasible. In other cases, lack of operable windows or other building characteristics prevented schools from employing this strategy.

The study quoted a survey participant: “Opening windows poses safety and air quality concerns from buses and car exhaust in addition to temperature control and noise issues. Additional fans utilized in space would potentially increase the spread [of] infectious aerosols through the space."

Better monitoring

The pandemic has focused attention on the fact that not enough schools were carefully monitoring the air quality in their classrooms and other school spaces. Only two-thirds of survey respondents were regularly monitoring indoor air quality before the pandemic, an indication that staffing and funding for regular monitoring and data collection has not been a priority for many schools.

On the other hand, the survey results suggest that the Covid-19 pandemic has increased awareness of indoor air quality concerns in school facilities and that the priority given to indoor air quality during the pandemic is likely to remain in place. About 70% of the districts responding to the survey say that they plan to continue at least some of the indoor air strategies they have embraced.

“A lot of inner-city kids suffer from asthma, so air quality is absolutely necessary,” one participant said. “Now, because the pandemic is affecting everybody, not just folks who suffer from asthma…ventilation is now the sexy word that’s on people’s minds.”

Improving school infrastructure has been a more difficult proposition in poorer communities with fewer resources.

“The funding of K-12 education and infrastructure is fundamentally inequitable, given its reliance on local wealth,” the report says. “The pandemic has only served to further entrench those inequities along racial and economic lines. School districts…that enjoyed a higher-than-average revenue stream remarked at how fortunate they were to have the resources to adapt and pivot as they needed to do.”

The significant infusion of dollars that school systems are getting from the federal Elementary & Secondary School Emergency Relief Fund may enable some poorer districts to allocate funding to improve indoor air quality and better protect the health and safety of students and staff.

“The science has been evident on the longstanding public health and economic benefits to enhancing indoor air quality,” the report concludes. “With additional investment in school infrastructure, school districts will be better prepared to manage air quality risks in the future.”

About the Author

Mike Kennedy | Senior Editor

Mike Kennedy, senior editor, has written for AS&U on a wide range of educational issues since 1999.

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