Equilibrium & Sustainability

Equilibrium — Using ancient methods to develop cleaner concrete

Future concrete buildings could be made more durable — and environmentally friendly — using the long-lost building techniques of ancient Rome, a new study has found. 

Use of an ancient Roman concrete-mixing technique called “hot mixing” created blocks that could heal themselves when cracked, according to the paper published in Science Advances. 

Such self-healing blocks allowed the Romans to build structures like aqueducts, monuments and stadiums that have survived for millennia amid wars, earthquakes and everyday urban pollution and chaos. 

Researchers said blocks treated with the method — in which concrete was mixed with reactive quicklime under continuous heat — knit themselves back together within a few weeks after being fractured.

Their ability to self-heal came from chemical flecks left by that hot quicklime — which combined with rainfall from natural limestone and sealed cracks in the concrete.  

Cracks in blocks that had been made without lime, by contrast — as all modern concrete is — never healed, the MIT team found. 

Building modern concrete with updated versions of these ancient methods could lead to longer-lived buildings — particularly in the realm of 3D-printed structures, MIT professor Admir Masic said. 

Welcome to Equilibrium, a newsletter that tracks the growing global battle over the future of sustainability. I’m Saul ElbeinSubscribe here or in the box below.

Today we’ll survey the damage from California’s continuing line of storms, which show little sign of stopping, and look at the Environmental Protection Agency’s efforts  to limit soot-related deaths.

California storms just keep coming

California towns battered by days of heavy storms had a brief respite Friday before the onslaught begins again next week, the National Weather Service (NWS) warned. 

Not over yet: Another atmospheric river is due to arrive on Monday in the West Coast, bringing more large destructive storms, The New York Times reported. 

Insult to injury: This week’s storms killed at least six people, flooded houses and wrecked beaches, according to the Los Angeles Times. 

Uprooting a legacy: The storms battered California’s urban and rural forests, killing thousands of trees in what one state official called “the signature of this particular event,” The New York Times reported. 

Tree branches and whole trunks knocked over by the wind damaged homes, levees and power lines, according to the Times. 

Future risk: The repeated blows of strengthened storms, mixed with wet and unstable soil, is knocking out more trees than before, state officials told reporters.

What kind of problems: Fallen trees in the backcountry could help fuel summer wildfires. 

More immediately, as more storms approach, branches knocked from fallen trees can clog levees and culverts, causing them to flood.

Southwest Airlines meltdown cost at least $725M

A catastrophic flight-routing meltdown over the holidays cost Southwest Airlines between $725 million and $825 million, the carrier told regulators on Friday. 

The company will lose as much as $425 million in revenue on refunded flights alone, our colleague Karl Evers-Hillstrom reported.  

What happened? Southwest’s system was not prepared to deal with the cascade of cancellations and missed connections caused by December’s extreme weather, The New York Times reported.  

What now? Southwest’s chief executive, Bob Jordan, has promised to accelerate improvements to the airline’s systems, The Hill reported. 

But Jordan has not provided further details on the timeline or cost of these improvements, The Hill reported.  

Undercounting costs: Southwest’s estimates of its costs only include direct expenses — rather than longer term costs from its very public failure.  

But reputational damage is only a risk if customers have other options — and in America’s highly concentrated airline market, they often don’t, experts told CBS.  

OSHA: AMERICAN AIRLINES RETALIATED AGAINST EMPLOYEES 

American Airlines allegedly retaliated against employees who reported that toxic fumes in plane cabins were making workers sick.

That’s according to a new investigation by the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA), based on a tip from a company whistleblower. 

American Airlines responds: A company spokesperson told Fortune that they “respectfully disagree” with the OSHA findings. 

What’s the penalty? OSHA proposed a fine of $6,837 for the company, which posted $483 million in profits in the third quarter of 2022.

EPA announces new soot rule

The Environmental Protection Agency (EPA) on Friday ratcheted down acceptable limits for soot, a dangerous environmental contaminant generally caused by burning fossil fuels. 

But many say the agency hasn’t gone far enough, 

Keeping levels down: The EPA cut down the allowable levels of soot from 12 micrograms per cubic meter to between 9 and 10 micrograms, our colleague Rachel Frazin reported.  

A final rule is expected later this year. 

What is soot, again? A kind of superfine air pollution — smaller than 2.5 microns — released when fuels are burned. 

It gets into the bloodstream and can cause asthma, heart attacks and premature death. 

Should levels be lower? The EPA estimated that 9,200 lives — another 5,000 above the level currently proposed — could be saved if levels were cranked down further, to 8 micrograms per cubic meter, Frazin reported. 

Exposure to harm: Levels below 8 micrograms mean exposing the population to “health harms that could have been avoided, and would miss a critical opportunity to meet President Biden’s environmental justice commitments,” Paul Billings, senior vice president at the American Lung Association, said in a statement. 

Community voice: Yvonka Hall, the executive director of the Northeast Ohio Black Health Coalition, criticized the new soot rule proposal in a statement. 

Follow-up Friday

Catching up on stories from earlier in the week. 

Federal firefighters get a pay raise 

Britain hits a wind record 

Tesla cuts prices across Asia 

Please visit The Hill’s Sustainability section online for more and check out other newsletters here. We’ll see you Monday.