Richard E. Peltier, UMass Amherst The Trump administration is “reconsidering” more than 30 air pollution regulations, and it offered industries a brief window to apply for exemptions that would allow them to stop following many air quality regulations immediately if approved. All of the exemptions involve rules finalized in 2024 and include regulations for hazardous air pollutants that cause asthma, heart disease and cancer. The results – if regulations are ultimately rolled back and if those rollbacks and any exemptions stand up to court challenges – could impact air quality across the United States. “Reconsideration” is a term used to review or modify a government regulation. While Environmental Protection Agency Administrator Lee Zeldin provided few details, the breadth of the regulations being reconsidered affects all Americans. They include rules that set limits for pollutants that can harm human health, such as ozone, particulate matter and volatile organic carbon. Zeldin wrote on March 12, 2025, that his deregulation moves would “roll back trillions in regulatory costs and hidden “taxes” on U.S. families.“ What Zeldin didn’t say is that the economic and health benefits from decades of federal clean air regulations have far outweighed their costs. Some estimates suggest every $1 spent meeting clean air rules has returned $10 in health and economic benefits.

How far America has come, because of regulations

In the early 1970s, thick smog blanketed American cities and acid rain stripped forests bare from the Northeast to the Midwest. Air pollution wasn’t just a nuisance – it was a public health emergency. But in the decades since, the United States has engineered one of the most successful environmental turnarounds in history. Thanks to stronger air quality regulations, pollution levels have plummeted, preventing hundreds of thousands of deaths annually. And despite early predictions that these regulations would cripple the economy, the opposite has proven true: The U.S. economy more than doubled in size while pollution fell, showing that clean air and economic growth can – and do – go hand in hand. The numbers are eye-popping. An Environmental Protection Agency analysis of the first 20 years of the Clean Air Act, from 1970 to 1990, found the economic benefits of the regulations were about 42 times greater than the costs. The EPA later estimated that the cost of air quality regulations in the U.S. would be about US$65 billion in 2020, and the benefits, primarily in improved health and increased worker productivity, would be around $2 trillion. Other studies have found similar benefits. That’s a return of more than 30 to 1, making clean air one of the best investments the country has ever made.

Science-based regulations even the playing field

The turning point came with the passage of the Clean Air Act of 1970, which put in place strict rules on pollutants from industry, vehicles and power plants. These rules targeted key culprits: lead, ozone, sulfur dioxide, nitrogen oxides and particulate matter – substances that contribute to asthma, heart disease and premature deaths. An example was the removal of lead, which can harm the brain and other organs, from gasoline. That single change resulted in far lower levels of lead in people’s blood, including a 70% drop in U.S. children’s blood-lead levels.

The results have been extraordinary. Since 1980, emissions of six major air pollutants have dropped by 78%, even as the U.S. economy has more than doubled in size. Cities that were once notorious for their thick, choking smog – such as Los Angeles, Houston and Pittsburgh – now see far cleaner air, while lakes and forests devastated by acid rain in the Northeast have rebounded.

And most importantly, lives have been saved. The Clean Air Act requires the EPA to periodically estimate the costs and benefits of air quality regulations. In the most recent estimate, released in 2011, the EPA projected that air quality improvements would prevent over 230,000 premature deaths in 2020. That means fewer heart attacks, fewer emergency room visits for asthma, and more years of healthy life for millions of Americans.

The economic payoff

Critics of air quality regulations have long argued that the regulations are too expensive for businesses and consumers. But the data tells a very different story. EPA studies have confirmed that clean air regulations improve air quality over time. Other studies have shown that the health benefits greatly outweigh the costs. That pays off for the economy. Fewer illnesses mean lower health care costs, and healthier workers mean higher productivity and fewer missed workdays. The EPA estimated that for every $1 spent on meeting air quality regulations, the United States received $9 in benefits. A separate study by the non-partisan National Bureau of Economic Research in 2024 estimated that each $1 spent on air pollution regulation brought the U.S. economy at least $10 in benefits. And when considering the long-term impact on human health and climate stability, the return is even greater.

The next chapter in clean air

The air Americans breathe today is cleaner, much healthier and safer than it was just a few decades ago. Yet, despite this remarkable progress, air pollution remains a challenge in some parts of the country. Some urban neighborhoods remain stubbornly polluted because of vehicle emissions and industrial pollution. While urban pollution has declined, wildfire smoke has become a larger influence on poor air quality across the nation. That means the EPA still has work to do. If the agency works with environmental scientists, public health experts and industry, and fosters honest scientific consensus, it can continue to protect public health while supporting economic growth. At the same time, it can ensure that future generations enjoy the same clean air and prosperity that regulations have made possible. By instead considering retracting clean air rules, the EPA is calling into question the expertise of countless scientists who have provided their objective advice over decades to set standards designed to protect human lives. In many cases, industries won’t want to go back to past polluting ways, but lifting clean air rules means future investment might not be as protective. And it increases future regulatory uncertainty for industries. The past offers a clear lesson: Investing in clean air is not just good for public health – it’s good for the economy. With a track record of saving lives and delivering trillion-dollar benefits, air quality regulations remain one of the greatest policy success stories in American history. This article, originally published March 12, 2025, has been updated with the administration’s offer of exemptions for industries. Richard E. Peltier, Professor of Environmental Health Sciences, UMass Amherst This article is republished from The Conversation under a Creative Commons license. Read the original article.

David Garofalo, Kennesaw State University One of the most powerful objects in the universe is a radio quasar – a spinning black hole spraying out highly energetic particles. Come too close to one, and you’d get sucked in by its gravitational pull, or burn up from the intense heat surrounding it. But ironically, studying black holes and their jets can give researchers insight into where potentially habitable worlds might be in the universe. As an astrophysicist, I’ve spent two decades modeling how black holes spin, how that creates jets, and how they affect the environment of space around them.

What are black holes?

Black holes are massive, astrophysical objects that use gravity to pull surrounding objects into them. Active black holes have a pancake-shaped structure around them called an accretion disk, which contains hot, electrically charged gas. The plasma that makes up the accretion disk comes from farther out in the galaxy. When two galaxies collide and merge, gas is funneled into the central region of that merger. Some of that gas ends up getting close to the newly merged black hole and forms the accretion disk. There is one supermassive black hole at the heart of every massive galaxy. Black holes and their disks can rotate, and when they do, they drag space and time with them – a concept that’s mind-boggling and very hard to grasp conceptually. But black holes are important to study because they produce enormous amounts of energy that can influence galaxies. How energetic a black hole is depends on different factors, such as the mass of the black hole, whether it rotates rapidly, and whether lots of material falls onto it. Mergers fuel the most energetic black holes, but not all black holes are fed by gas from a merger. In spiral galaxies, for example, less gas tends to fall into the center, and the central black hole tends to have less energy. One of the ways they generate energy is through what scientists call “jets” of highly energetic particles. A black hole can pull in magnetic fields and energetic particles surrounding it, and then as the black hole rotates, the magnetic fields twist into a jet that sprays out highly energetic particles. Magnetic fields twist around the black hole as it rotates to store energy – kind of like when you pull and twist a rubber band. When you release the rubber band, it snaps forward. Similarly, the magnetic fields release their energy by producing these jets.

These jets can speed up or suppress the formation of stars in a galaxy, depending on how the energy is released into the black hole’s host galaxy.

Rotating black holes

Some black holes, however, rotate in a different direction than the accretion disk around them. This phenomenon is called counterrotation, and some studies my colleagues and I have conducted suggest that it’s a key feature governing the behavior of one of the most powerful kinds of objects in the universe: the radio quasar. Radio quasars are the subclass of black holes that produce the most powerful energy and jets. You can imagine the black hole as a rotating sphere, and the accretion disk as a disk with a hole in the center. The black hole sits in that center hole and rotates one way, while the accretion disk rotates the other way. This counterrotation forces the black hole to spin down and eventually up again in the other direction, called corotation. Imagine a basketball that spins one way, but you keep tapping it to rotate in the other. The tapping will spin the basketball down. If you continue to tap in the opposite direction, it will eventually spin up and rotate in the other direction. The accretion disk does the same thing. Since the jets tap into the black hole’s rotational energy, they are powerful only when the black hole is spinning rapidly. The change from counterrotation to corotation takes at least 100 million years. Many initially counterrotating black holes take billions of years to become rapidly spinning corotating black holes. So, these black holes would produce powerful jets both early and later in their lifetimes, with an interlude in the middle where the jets are either weak or nonexistent. When the black hole spins in counterrotation with respect to its accretion disk, that motion produces strong jets that push molecules in the surrounding gas close together, which leads to the formation of stars. But later, in corotation, the jet tilts. This tilt makes it so that the jet impinges directly on the gas, heating it up and inhibiting star formation. In addition to that, the jet also sprays X-rays across the galaxy. Cosmic X-rays are bad for life because they can harm organic tissue. For life to thrive, it most likely needs a planet with a habitable ecosystem, and clouds of hot gas saturated with X-rays don’t contain such planets. So, astronomers can instead look for galaxies without a tilted jet coming from its black hole. This idea is key to understanding where intelligence could potentially have emerged and matured in the universe.

Black holes as a guide

By early 2022, I had built a black hole model to use as a guide. It could point out environments with the right kind of black holes to produce the greatest number of planets without spraying them with X-rays. Life in such environments could emerge to its full potential.

Where are such conditions present? The answer is low-density environments where galaxies had merged about 11 billion years ago. These environments had black holes whose powerful jets enhanced the rate of star formation, but they never experienced a bout of tilted jets in corotation. In short, my model suggested that theoretically, the most advanced extraterrestrial civilization would have likely emerged on the cosmic scene far away and billions of years ago. David Garofalo, Professor of Physics, Kennesaw State University This article is republished from The Conversation under a Creative Commons license. Read the original article.

Todd L. Ely, University of Colorado Denver With the Trump administration seeking to cut federal funding for colleges and universities, you might be wondering whether the endowments of these institutions of higher education might be able to fill those gaps. Todd L. Ely, a professor of public administration at the University of Colorado Denver, explains what endowments are and the constraints placed on them.

What’s an endowment?

Endowments are pools of financial investments that belong to a nonprofit. These assets produce a revenue stream, typically from dividends, interest and realized capital gains. The funds endowments hold usually originate as charitable donations made to support an institution’s mission. In most cases with higher education endowments, this wealth, which helps buoy a nonprofit’s budget, is supposed to last forever. Contributions to endowments are tax-deductible for donors who itemize their tax returns. Once these funds are invested, they grow generally tax-free. But beginning in 2018, the federal government imposed a 1.4% excise tax on dozens of higher education institutions with relatively large endowments. Few colleges or universities have a single endowment fund. That’s because the donors who provide gifts large and small to the school over the years direct their donations to different funds reserved for specific purposes. Harvard University’s endowment, worth $53.2 billion at the end of its 2024 fiscal year, for example, consists of roughly 14,600 distinct funds. All told, money distributed from endowments covered more than 15%, on average, of college and university operating expenses in 2024. Some of America’s institutions of higher education, however, lean much more heavily than that on their endowments to pay their bills.

How do endowments influence higher education?

Endowments can serve multiple purposes. In 2024, nearly half of all higher education spending paid for with endowment revenue funded scholarships and other kinds of aid for students, while almost 18% supported academic programs. Just under 11% paid for professors’ compensation, and almost 7% helped pay for running and maintaining campus facilities. More broadly, endowments can help shield schools from financial hardships and maintain their long-term reputations. When they’re set up to carry on in perpetuity, endowments must benefit both current and future generations. So when donors give to an endowment, they are arguably investing in the long-term viability of the institution. This long-term focus suggests that endowments aren’t just rainy-day funds or financial reserves.

Why can’t endowment funds be spent freely?

At the end of the 2023 fiscal year, U.S. higher education endowments held a total of more than $907 billion. That is a lot of money, but it’s still less than the combined wealth of America’s five richest people. Like individual wealth, endowment assets are heavily concentrated in the U.S. Many colleges and universities have small or no endowments. Nearly 60% of them total less than $50 million. The top 25, which includes several public universities in states such as Michigan and Texas, account for more than half of all endowment assets. And even when schools have large endowments, the individual funds that compose them are bound by a wide array of restrictions. Some of that money can be spent however the school would like. Other funds are dedicated to a clearly defined purpose. When endowment funds are restricted, the school gets little discretion in how to spend them. At Harvard, for example, there’s a Hollis Professorship of Divinity at Harvard University. It was established in 1721 through a gift from a London merchant. Based on the terms of that long-ago donation, the earnings and growth of the donated funds continue to honor the donor’s intent by supporting the position, regardless of what the university needs. Alternatively, endowments may receive donations that are temporarily restricted. Known as “term” endowments, the assets they hold can be used once donor-imposed conditions are fulfilled. Institutions frequently designate some of their unrestricted funds as “quasi” endowments, usually earmarked for specific strategic purposes. This board-designated quasi-endowment does not carry legal restrictions and can be spent more freely. About 40% of higher education endowment assets are subject to permanent restrictions, 30% are temporarily restricted, and 29% are reserved for quasi-endowment use.

How are decisions over endowment funds made?

The decision-making authority over endowments typically rests with a college or university’s governing board. Those boards establish endowment payout policies that guide how much of the endowment and its earnings can be spent each year, while attempting to preserve the purchasing power of the investments over the long term. The policies take expectations regarding investment earnings and inflation into account, while smoothing annual payouts by using a percentage of the value of the endowment over multiple years as opposed to a single point in time. This payout tends to amount to about 5% of all assets. That share averaged 4.8% in 2024. U.S. institutions of higher education spent nearly $35.5 billion derived from their endowments in the 2023 fiscal year. Colleges and universities that depend more heavily on their endowment funds to cover their current obligations may choose to invest more conservatively. In recent years, many higher education endowments have obtained more complex investments, such as private equity, real assets and stakes in hedge funds. Endowments of nonprofit colleges and universities are also governed in most states by a state law known as the Uniform Prudent Management of Institutional Funds Act. This law encourages cautious investments and restrained spending. These restrictions mean that annual payouts are generally modest. That leaves endowments ill-equipped to respond to abrupt and large shifts in their funding needs. The John F. Kennedy School of Government, commonly referred to as Harvard Kennedy School, is a member of The Conversation U.S. Todd L. Ely, Associate Professor of Public Administration; Director, Center for Local Government, University of Colorado Denver This article is republished from The Conversation under a Creative Commons license. Read the original article.