Since last summer, leaders of the state's largest teachers union have been telling anyone who would listen, including The Day's Editorial Board, that the air inside many school buildings was making it inhumanely hard to teach and to learn.

Most Connecticut schools have some kind of air conditioning, but the systems can be unreliable. Schools from the 1960s and '70s may have windows that don't open wide enough to ventilate the classroom if the AC falters. And a school that depends on window breezes runs into the problem that on many days in Connecticut's warmer months the outside air is unhealthy as well. Starting in the '90s, new schools were built for defense against intruders, and windows got smaller and tighter.

An estimated 20 percent of schools in Connecticut has had no updates to make classroom air more breathable, especially as the school day goes on. Since the arrival of COVID-19 and the reopening of schools last fall, the need for effective ventilation and air filtration has become urgent.

Like eating breakfast, having clean, unstuffy air to breathe is a prerequisite for staying alert and concentrating on lessons. In a time of pandemic, filtering the air can be a prequisite to staying uninfected and in school.

"HVAC is a building block," Kate Dias told The Day in a visit just before schools fully re-opened. "Bad temperatures affect learning." Dias is the president of the CEA, the Connecticut Education Association. Before this year she taught statistics and geometry at Manchester High School.

"I love data," she said. "It tells the story."

The data being used to push for better air quality is included in the results of a 2021 survey that showed one-third of Connecticut school districts reporting they lacked sufficient funds to start an indoor air quality program in about one-fifth of the state's schools. Locally, that includes East Lyme, New London and Salem.

The Lamont administration conducted the survey last spring but only recently released the results after requests from the Accountability Project of Connecticut Public, formerly known as Connecticut Public Radio. Meanwhile, the CEA got the attention of the media and the Connecticut Conference of Municipalities, which has listed education measures first on its legislative agenda and state bond funds for HVAC repairs and air filtration improvements as number one among its education priorities.

For many months, however, Gov. Lamont has lumped air quality improvement in with more social workers, teachers and after-school programs as a matter of priorities for local officials deciding how to spend their federal Covid relief allotments. The Stonington Board of Finance, for one, decided against spending $1.4 million toward improving HVAC at the middle school, with some board members saying the school system failed to be transparent about what it would do with its own $4.1 million in Covid relief funds. The board ended up committing $100,000 for the middle school in the plan that went to a town meeting in October, and noted that school officials were seeking state funds.

On Tuesday, the administration's chief operating officer, Josh Geballe, told state legislators at a school construction meeting that in light of the state's improving fiscal situtation, air quality upgrades are now on the table, the Connecticut Mirror reported. Bipartisan support for upgrading HVAC in schools is also increasing in the legislature as the 2022 session nears.

Six months ago, with fingers still crossed that there would be no overwhelming Covid winter surge, the goal was to get back to "normal" in schools. Tough lessons have been learned about students' mental health after isolation, the unwillingness of some families to have their children vaccinated, and the unforeseen contagiousness of the omicron variant. Fortunately, the administration and legislators seem to be listening to the evidence that clean, comfortable air in school can help with those issues and create a better environment for learning, and that it's their job to support it.

Lisa McGinley is a member of The Day Editorial Board.