With help from Tyler Weyant

BREATHING EASIER — The other day, I sat across the desk of a leading Covid expert.

We were both unmasked.

And we were inhaling what was probably the safest, healthiest, best monitored, and least virusy air I’ve breathed in years.

I was talking to Joseph Allen — an associate professor at Harvard’s T.H. Chan School of Public Health and director of its Healthy Buildings program — about ventilation, filtration, and safe indoor air. He was both aggravated and optimistic.

Aggravated because we are still not doing things that we know can reduce Covid infection and deaths (and slash Covid risks in schools) even though it’s not that complicated. And pots of American Rescue Plan money available for schools have not been fully tapped.

Optimistic because, however belatedly, buildings and indoor spaces are becoming safer — in part because big companies are figuring out that nontoxic buildings are better than “sick” ones. Allen’s research has shown that our lungs like healthy buildings, but so do our brains. We think, learn and perform better when we’re not inhaling invisible toxic gunk.

At the start of the pandemic, which is beginning to feel like a lifetime ago, scientists and public health officials focused on “fomites” — coronavirus transmission via surfaces. While cleaning is never a bad idea, elevator buttons, subway turnstiles and grocery packages did not turn out to be a big factor in Covid transmission.

Attention turned to respiratory droplets, prompting all those circles and decals on floors reminding us to stay six feet apart, which was not the spatial amulet we hoped it would be. Droplets are a factor but not, Allen and like-minded scientists argued from early 2020, the biggest danger.

What we’ve been overlooking, or at least underemphasizing, is that smaller particles transmit the virus. A five-micron particle can travel more than six feet and linger in the air for 30 minutes, sometimes more, invisibly and invidiously. If you ignore that — which, Allen noted, is largely what the Centers for Disease Control and Prevention and other expert groups have done — you end up bleach-wiping ketchup bottles instead of opening a window.

A better solution, for Covid and other ailments: improved ventilation — bringing more outside air into buildings and better circulating air. And filtration — cleaning the indoor air. Many, if not enough, schools and businesses have adopted them. And they work, in all kinds of buildings, from homeless shelters to high-rises.

“People often ignore the indoor environment when they think about their health,” Allen told Nightly. “They think about exercise, eating healthy, not smoking, outdoor pollution. But not about where we spend most of our time: indoors.”

That’s changing. Ventilation has begun to appear far more regularly in virus-fighting strategies, which is “the crux,” Allen said, given that this coronavirus is spread “nearly entirely indoors” in buildings with poor ventilation and filtration.

Buildings “were designed to protect equipment not people,” he said. “And you wonder why we have a disaster on our hands.”

The fixes basically involve bringing in more outdoor air, using better filters, and air changeovers four to six times per hour. Without getting too technical about why MERV 13 filters are better than MERV 8s, let’s just say it’s not too hard, nor is it usually too expensive.

In some cases it’s as simple as adjusting the settings on air intake systems in a building. In others, it’s getting higher quality filters. Sometimes it’s just replacing some windows so they open. And yes, sometimes it’s more complicated. But most places — work, school or play — could do this without going broke.

Portable machines with HEPA air filters can help. And there are versions for homes, too.

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Allen has been particularly frustrated that more schools didn’t draw on “off the shelf, plug and play” technology.

“I’ve answered every call from every school that’s ever called me,” he said. “Many places did it well. People who got the message did it well.”

But indoor air just hasn’t gotten the attention it needs, he said, including from top U.S. public health officials. “The message didn’t take hold,” he said, although more recently the Biden administration has elevated its importance.

The message should have been: “Vaccines. Therapeutics. Masking. Testing — Ventilation.”

“Building science was not at the table,” he said. He put it this way at another moment: “It’s been neglected and ignored for a long time. … Public health hasn’t had a seat at the table when it comes to our built environment.”

While it may take time to change federal laws, standards and codes, businesses are moving ahead, he said.

“If you convince a CEO that this is important on a Friday — on Monday morning it will change.”

— Senate fails to pass abortion rights bill — again: The Senate once again failed to advance abortion rights legislation today, in a largely symbolic effort Democrats mounted in response to the Supreme Court’s draft opinion overturning Roe v. Wade. In a 49-51 vote, the Senate rejected the Democratic legislation, with Sen. Joe Manchin (D-W.Va.) and all Republicans voting against the measure. While the outcome was no surprise and mirrored a similar vote on abortion protections the Senate took in February, Majority Leader Chuck Schumer suggested the court’s draft opinion, published by POLITICO last week, had raised the stakes.

— U.S. grapples with Russian blockade endangering global food supplies: A growing number of U.S. lawmakers are pressing the Biden administration to establish a humanitarian corridor in the Black Sea, in an effort to circumvent a Russian military blockade that’s threatening to financially strangle Ukraine while holding back millions of tons of grain from the world food supply. European Union officials, with U.S. help, are set to announce a new effort to ship Ukrainian grain over land routes via rail and truck, but the land routes are expensive and time-consuming to establish, and even the planners acknowledge they won’t make up for the volume that can be moved by seaport.