GEOFF BENNETT: With the new school year under way, we're going to spend some time now looking at significant challenges that students, families and districts around the country are facing.

Stephanie Sy starts us off with a look at how this heat wave in much of the country is creating problems for schools.

STEPHANIE SY: Geoff, these near-triple-digit temperatures have led to school districts either closing or dismissing students early in at least nine states this week.

It's also raised questions about old school buildings, the lack of air conditioning and ventilation concerns that arose during the peak of COVID.

Joseph Allen has long focused on this as the director of the Healthy Buildings Program at Harvard's Chan School of public health.

Joe, it's a pleasure to have you on the "NewsHour."

I want to start by asking, what should schools be doing now and going forward to better prepare for extreme heat?

JOSEPH ALLEN, Harvard T.H.

Chan School of Public Health: Yes, so thanks for having me on.

Unfortunately, this was entirely predictable.

I mean, the climate crisis is hitting us on two fronts.

We're having longer, more intense heat waves that start earlier in the season and showing up later in the season, like we have now.

This is a particular problem for schools in traditionally cool weather climates that were designed to retain heat.

So, what to do right now?

At a minimum, we have to provide cooling for students, right?

That is the simple answer.

It's an obvious fix.

The money is actually there.

And it doesn't have to be more complicated than that.

There are other things we need to do, but, in the immediate term, we can't have kids missing school because of heat.

And this problem is only going to get worse.

STEPHANIE SY: And going forward, should -- do they need to retrofit these buildings to better handle the realities of climate change?

JOSEPH ALLEN: Yes, they do.

And it's -- fortunately, it's not that hard.

It's not that expensive.

The money is there.

And, also, I think we have to stop thinking of these as separate crises.

And the crises I'm talking about are things like extreme heat events or exposure to wildfire smoke and air pollution or COVID-19 and influenza.

All of these crises run through our buildings.

And they're crises because we're not operating and designing our school buildings correctly.

If we improve ventilation and filtration, we address COVID-19, influenza, RSV, outdoor air pollution, wildfire smoke and, yes, extreme heat.

So we're having these conversations all through the summer about different crises.

They're all related.

They all run through our buildings.

And so do the solutions.

STEPHANIE SY: Besides immediately installing HVAC systems in Northeast schools and ventilation systems, won't it take quite a long time to address the fact that so many schools in this country are just in old buildings?

JOSEPH ALLEN: Well, it seems like this is an overwhelming problem, but, fortunately, the solutions are really straightforward.

And there are things you can do in any kind of building to make it more comfortable, more safe, improve ventilation, things like using heat pumps, which are also good for the climate crisis, in the sense that it can provide cooling through the use of electricity and heating through the use of electricity.

I know school districts that did exactly that, installed heat pump pumps for each classroom.

There are even basic things like air conditioning for the window units while these larger replacements that need to take place are happening.

I reject the notion that we can't act because it's too hard or too long.

This money has been sitting around for years.

So we had the COVID crisis, and it wasn't spent.

So this idea that maybe it was just too hard or too long, well, it's been years.

Why hasn't that been spent?

And if we go even back longer, it's been decades since we have improved our school infrastructure.

I tell you, this moment makes me really nervous, because we're never going to get these kind of funds again for our schools.

We haven't in the history of our schools.

And it's a chance to fix what has been decades of neglect of our school buildings.

And we have to take a step back and recognize that the way our buildings are designed and running are having a massive impact on our kids' learning.

And that's across respiratory infections all the way through extreme temperature and pollution.

And it's not hard to do.

And there's still -- it's -- the time to act was yesterday.

And if you couldn't do it yesterday, you have to do it right now.

STEPHANIE SY: You keep saying that the money is there.

Are you referring to the American Rescue Plan money, the billions of dollars that were put towards schools at the peak of the pandemic?

Should they have prioritized air conditioning and ventilation and air quality higher?

JOSEPH ALLEN: Yes, absolutely.

That's the money I'm referring to.

It's a once-in-a-generation opportunity to fix our crumbling school infrastructure.

Billions and billions of dollars were allocated towards school to improve ventilation and filtration to address COVID-19.

The shocking thing -- and everyone should be really upset about this -- is that, in many states, the majority of that money has not been spent.

So think about that.

We had a COVID crisis, tens of millions of kids out of school, an airborne virus.

We know ventilation and filtration help, and that money wasn't spent.

Now, that money is still available, but not for much longer.

If we make these improvements to the school building for COVID, it helps against those other infectious diseases and threats like this.

It's totally unacceptable that we're closing schools due to extreme heat, when we know what the solution is.

The money's there.

Absolute basics in this country, we have to provide safe, healthy and comfortable learning environments for our students and our teachers.

I find this totally unacceptable.

STEPHANIE SY: Yes.

And This leads me to the questions about achievement and the heat and these other issues' effects on student behavior.

And I read a statistic that researchers at Harvard have found heat effects account for 13 percent of the racial achievement gaps.

So are we also seeing uneven impacts along racial lines?

JOSEPH ALLEN: Well, yes, we have the objective scientific data that shows it.

And I don't think this would surprise anybody, but when you look at things like air quality or ventilation standards or rates of outdoor air brought into schools, we see that in schools that are predominantly Black or Hispanic student populations have even lower ventilation rates.

We see the same thing in schools where the majority of students are on free or reduced lunch, so lower-income students.

We see these schools have lower ventilation rates.

Totally unacceptable that we have anyone in any school anywhere has an uncomfortable, unsafe, unhealthy environment, and then we also see disparities across race, ethnicity, and income.

STEPHANIE SY: Joe Allen at the Harvard School of Public Health, thank you so much for your insights.

JOSEPH ALLEN: Yes, thanks for having me on.