Parents and guardians of children in Baltimore County Public Schools, and other community stakeholders, have raised questions for months about air filtration systems in schools and whether indoor air is safe amid the coronavirus pandemic. One parent, frustrated with government responsiveness, decided to take matters into her own hands.
Although the county school system’s facilities management department has said that systems at all schools have been inspected to make sure they meet code, parent and atmospheric scientist Elizabeth Dahl argues that the code used is a “minimum standard” and that ventilation may not be sufficient to reduce the spread of diseases like COVID-19.
For this reason, Dahl, who holds a doctorate in Earth System Science from the University of California Irvine, tested the air quality last fall in Baltimore County schools, including the two her children attend, through a citizen science project, which, in the final analysis, returned results that she found to be concerning.
She then circulated a petition, which has gained over 300 signatures from BCPS staff, parents and guardians, and other community members, asking the school system to provide portable high-efficiency particulate air filtration units to all classrooms and indoor spaces where children gather.
The HEPA filtration units are 99.97% efficient at capturing human-generated viral particles associated with COVID-19, according to the Centers for Disease Control and Prevention.
And though officials said that the type of purifiers delivered to schools contain HEPA filters, the purifiers are not in all classrooms, Dahl has observed. Portable HEPA filters, studies show, can filter air in spaces that have limited to no integrated mechanical ventilation.
The petition also suggested that the school system should upgrade to at least a MERV-13 filter for all HVAC systems. MERV, or minimum efficiency reporting value, measures effectiveness of an air filter, and MERV-13 filters are recommended by the CDC and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), a global professional association, for reducing virus transmission.
BCPS uses the lower-rated MERV-8 filters; however, last school year, the school system started changing out the filters five times a year rather than quarterly, as they had before.
“Inspections of the ventilation and circulation systems have been performed at all schools to verify the ventilation, circulation and filtration is functioning as designed,” BCPS facilities administrative assistant Deborah Soper said in an email to Dahl. “Facilities’ staff will continue to perform scheduled preventative maintenance on HVAC systems and are changing filters more frequently.”
“The systems, as designed, are not adequate,” Dahl said in an email to multiple school officials. “If filters are less than MERV-13, it doesn’t matter how often you change them, they still cannot filter virus and bacteria particles even when new.”
In her petition, Dahl brought up new initiatives in Howard County, where MERV-13 filters were provided for every classroom, and in Baltimore City, where HVAC system filters were upgraded to MERV-13 where possible, and, where filters could not be upgraded, portable filtration units were provided.
Dahl sent the petition to school officials three times, and received no response, she said.
“Complete radio silence from all board members, the superintendent, and the area superintendents, as well as the facilities department,” she said in a Feb. 11 email to The Avenue.
That was after several months of her pushing the issue, with no meaningful action taken by the school system, Dahl said.
On top of sending numerous emails to BCPS, she also submitted a Public Information Act Request to the state seeking records of the facilities department’s work on air handling at Villa Cresta Elementary and Parkville Middle schools, specifically between March 2020 and July 2021, as to whether the schools meet standards set by the ASHRAE.
No such records exist, BCPS General Counsel Margaret-Ann Howie said in response to Dahl’s PIA request.
“Baltimore County government mandates that all new buildings and system renovations follow the International Mechanical Code (IMC) 2015,” Howie said, adding that it has been the practice of the school system to follow “each manufacturer’s standards for HVAC systems; not ASHRAE standard.”
Jurisdictions can choose to adopt IMC for HVAC systems, yet the code, Dahl noted, predates the pandemic.
Dahl, in a later email, clarified that she was asking for documentation and / or data showing that the standards used are, in fact, met. Howie then, after answering Dahl’s other queries, advised that any additional requests would cost her, as staff have spent “over three and a half hours” processing her request, exceeding the 2-hour time limit allowed by the law.
Not feeling as though her concerns were “adequately addressed,” Dahl developed her own assessment to show why she thought further analysis on the matter was needed.
She collected data in five-minute intervals using Aranet4 standalone monitors to measure carbon dioxide in the air – carbon dioxide, studies indicate, can serve as a proxy for COVID-19 transmission. For several consecutive days, monitors were placed in classrooms, or students carried them, all for estimated ventilation rates.
Data was collected at eight local schools, including Villa Cresta Elementary and Parkville Middle ,the schools that Dahl’s two children attend. She also gathered data at two other elementary schools, three other middle schools and one high school.
Dahl found, through the citizen science project, that Villa Cresta and Fullerton Elementary School appeared to be the most well-ventilated schools of those studied, while Parkville Middle and Warren Elementary appeared to be among the most poorly ventilated.
A classroom at Villa Cresta, for example, still showed carbon dioxide levels exceeding 800 parts per million, the target benchmark for good ventilation as suggested by the CDC, for 31% of the day. Moreover, a Parkville Middle School student was exposed to air exceeding the benchmark for 82% of the school day.
At 800 ppm, 1% of the air you are breathing has been exhaled by someone else, according to the CDC, and the respiratory rate of a school-age child is 14 to 24 breaths per minute. As such, a child in a typical 90-minute class period, will take between 12 and 22 breaths of air from another person.
Dahl said that the data is limited, partly because she had little to no control over placement of the carbon dioxide monitors, or whether windows or doors were open in the students’ classrooms.
Still, the data she found was interesting, she said, in that individual students at Parkville Middle, Parkville High and Pine Grove Middle spent most of their school days in spaces where carbon dioxide levels exceeded 1,000 ppm. Also, a classroom at Warren Elementary School showed levels exceeding 1,000 ppm for 92% of the school day.
In order to share information about cleaning the air in schools and progress on those efforts, Dahl created the Facebook group “Air Filtration for Baltimore County & Greater Baltimore Area Schools.”
Member of that group and Baltimore County Parent and Student Coalition Vice President Mary Taylor joined in the campaign, testifying at a recent public hearing on the school board’s fiscal year 2023 budget about the need for schools to increase filter ratings to MERV-13 or provide portable HEPA air cleaners.
“Many of our schools,” she said, “continue to be poorly ventilated and are operating without filtration. This is not just a pandemic issue; this is an issue of equity and justice for all students in Baltimore County who deserve to breathe clean air in school.”
She adds that air ventilation rates, even outside of a pandemic, can impact student health and learning outcomes, which research has, in fact, shown.
Some progress on improving air quality in schools could be seen at the state level this year as well. Legislation, which would require each county school board to employ a qualified investigator to conduct air quality tests in public schools and then post the results online, will receive a hearing on Feb. 24. Several Baltimore County delegates are co-sponsoring the House version of the bill, and Sen. Kathy Klausmeier, representing District 8, is sponsoring the Senate bill.
“BCPS employs a variety of engineers, professionals, and staff to ensure BCPS facilities are safe and meet the needs of our students and staff,” a BCPS spokesperson said in a Feb. 8 email to the Avenue. “In addition, all mechanical systems in our schools are required to provide enough ventilation for maximum space occupancy, and during the pandemic extra efforts have been made to inspect all equipment for proper operation and safety, including addressing any enhancements and repairs that have been needed.”