Iain Boyd, University of Colorado Boulder

The recent spate of unidentified drone sightings in the U.S., including some near sensitive locations such as airports and military installations, has caused significant public concern.

Some of this recent increase in activity may be related to a September 2023 change in U.S. Federal Aviation Administration regulations that now allow drone operators to fly at night. But most of the sightings are likely airplanes or helicopters rather than drones.

The inability of the U.S. government to definitively identify the aircraft in the recent incidents, however, has some people wondering, why can’t they?

I am an engineer who studies defense systems. I see radio frequency sensors as a promising approach to detecting, tracking and identifying drones, not least because drone detectors based on the technology are already available. But I also see challenges to using the detectors to comprehensively spot drones flying over American communities.

How drones are controlled

Operators communicate with drones from a distance using radio frequency signals. Radio frequency signals are widely used in everyday life such as in garage door openers, car key fobs and, of course, radios. Because the radio spectrum is used for so many different purposes, it is carefully regulated by the Federal Communications Commission.

Drone communications are only allowed in narrow bands around specific frequencies such as at 5 gigahertz. Each make and model of a drone uses unique communication protocols coded within the radio frequency signals to interpret instructions from an operator and to send data back to them. In this way, a drone pilot can instruct the drone to execute a flight maneuver, and the drone can inform the pilot where it is and how fast it is flying.

Identifying drones by radio signals

Radio frequency sensors can listen in to the well-known drone frequencies to detect communication protocols that are specific to each particular drone model. In a sense, these radio frequency signals represent a unique fingerprint of each type of drone.

In the best-case scenario, authorities can use the radio frequency signals to determine the drone’s location, range, speed and flight direction. These radio frequency devices are called passive sensors because they simply listen out for and receive signals without taking any active steps. The typical range limit for detecting signals is about 3 miles (4.8 kilometers) from the source.

These sensors do not represent advanced technology, and they are readily available. So, why haven’t authorities made wider use of them?

Challenges to using radio frequency sensors

While the monitoring of radio frequency signals is a promising approach to detecting and identifying drones, there are several challenges to doing so.

First, it’s only possible for a sensor to obtain detailed information on drones that the sensor knows the communication protocols for. Getting sensors that can detect a wide range of drones will require coordination between all drone manufacturers and some central registration entity.

In the absence of information that makes it possible to decode the radio frequency signals, all that can be inferred about a drone is a rough idea of its location and direction. This situation can be improved by deploying multiple sensors and coordinating their information.

Second, the detection approach works best in “quiet” radio frequency environments where there are no buildings, machinery or people. It’s not easy to confidently attribute the unique source of a radio frequency signal in urban settings and other cluttered environments. Radio frequency signals bounce off all solid surfaces, making it difficult to be sure where the original signal came from. Again, the use of multiple sensors around a particular location, and careful placement of those sensors, can help to alleviate this issue.

Third, a major part of the concern over the inability to detect and identify drones is that they may be operated by criminals or terrorists. If drone operators with malicious intent know that an area targeted for a drone operation is being monitored by radio frequency sensors, they may develop effective countermeasures. For example, they may use signal frequencies that lie outside the FCC-regulated parameters, and communication protocols that have not been registered. An even more effective countermeasure is to preprogram the flight path of a drone to completely avoid the use of any radio frequency communications between the operator and the drone.

Finally, widespread deployment of radio frequency sensors for tracking drones would be logistically complicated and financially expensive. There are likely thousands of locations in the U.S. alone that might require protection from hostile drone attacks. The cost of deploying a fully effective drone detection system would be significant.

There are other means of detecting drones, including radar systems and networks of acoustic sensors, which listen for the unique sounds drones generate. But radar systems are relatively expensive, and acoustic drone detection is a new technology.

The way forward

It was almost guaranteed that at some point the problem of unidentified drones would arise. People are operating drones more and more in regions of the airspace that have previously been very sparsely populated.

Perhaps the recent concerns over drone sightings are a wake-up call. The airspace is only going to become much more congested in the coming years as more consumers buy drones, drones are used for more commercial purposes, and air-taxis come into use. There’s only so much that drone detection technologies can do, and it might become necessary for the FAA to tighten regulation of the nation’s airspace by, for example, requiring drone operators to submit detailed flight plans.

In the meantime, don’t be too quick to assume those blinking lights you see in the night sky are drones.

Iain Boyd, Director of the Center for National Security Initiatives and Professor of Aerospace Engineering Sciences, University of Colorado Boulder

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Simon F. Haeder, Texas A&M University

The U.S. health care system leaves much to be desired.

It is convoluted, fragmented, complex and confusing. Experts have also raised concerns about quality, and disparities are rampant. And, of course, it is excessively costly – far more so than in any other developed nation. Given these failings, it is not surprising that Americans are unhappy with their health care system.

As the public reaction to the killing of UnitedHealthcare CEO Brian Thompson has made clear, however, many Americans are perhaps most unhappy with their health insurers. Indeed, just 31% of Americans have a favorable view of the health insurance industry, according to a 2024 survey.

Yet, given the recent tragic events, as a health policy scholar, I think it would be prudent to take a step back and reflect on the broader health care system and how the U.S. got to this point.

Many sources of health care frustration

Few with any personal experience or professional expertise would describe U.S. health care as the gold standard of health care systems.

For a number of historical and political reasons, it is barely a “system” but rather a complex patchwork with countless different approaches to covering the costs of health care that include splitting the costs between individuals, employers and governments.

Governments also extensively regulate health and health care and, although in a diminished role today, serve as the providers of care through state and county hospitals as well as the Veterans Health Administration.

The result is a regulatory amalgam made up of countless entities. The Affordable Care Act reforms only added additional layers of laws and regulations to an already complex framework.

Yet, even beyond this general structure, Americans face many challenges. Indeed, no other health care system in the world is pricier. This involves costs for medical services but also extremely high administrative costs. Pharmaceuticals are just one example of the excessive financial burden carried by Americans.

For many Americans, these costs are too high, with an estimated 530,000 medical bankruptcies annually.

And despite that high price, concerns persist about quality and access.

In addition, the system tends to be highly inequitable and subject to countless disparities that make it harder for many poorer, rural and nonwhite Americans to access care.

The role of insurers

In the United States, insurers play a crucial role in connecting – and at times disconnecting – patients with the care they require.

They are also at the forefront of many of the starkest frustrations that Americans experience – even the ones they are not directly responsible for. While medical providers and pharmaceutical companies charge the world’s highest prices, it is generally up to insurers to tell patients how much they still have to pay or that their care won’t be covered. Insurers are also the ones who determine whether a drug is not covered or a doctor is “out of network,” meaning patients can’t get the specific treatment or care they desire.

To be sure, insurers are not just the messenger – they also add to many of the frustrations patients experience every day. For example, a patient may have to travel very far or wait a long time for an appointment if their provider network is too narrow or simply does not have enough providers. Moreover, the directories and searches that insurers use to show what providers are “in network” may be inaccurate, as they rarely get updated.

For many individuals, this can mean delayed or forgone care, which has major implications for their health and finances. For some, it can even lead to preventable deaths.

Some of the practices insurers are most infamous for, such as rescinding coverage over minor clerical issues and refusing to cover preexisting conditions, ended under the ACA. But some of these issues could return if the incoming Trump administration seeks to undo some of the ACA’s protections.

Even today, so called short-term, limited-duration health plans promise good coverage for lower premiums, but even basic items may not be covered. Many plans, for example, do not cover prescription drugs or even hospital emergency rooms.

Blame the system, not just the insurers

Why do insurers act the way they do? For many, the answer may seem simple: to make money. This, of course, rings true – insurers in the U.S. rake in billions of dollar. However, while they tend to be profitable, their margins generally range only from 3% to 5%.

But the story is more complicated than that. With government power limited, insurers are perhaps the only force in the U.S. health care industry trying to rein in rising costs in a health care system where everyone seeks to maximize their profits.

That means insurers take on the role of bad cop, doing things such as limiting access to certain care or doctors. But there are several prudent reasons for doing so; for instance, it’s in the public’s best interest when insurers do not cover drugs that have been shown ineffective or of low quality. And ultimately this does keep premiums lower than they would otherwise be. Of course, insurers and their CEOs profit handsomely in the process. And at times, their methods are ethically and legally questionable.

Ultimately, many if not most of the frustrations Americans experience with health care have their origins in a poorly designed system that is highly inefficient and offers countless opportunities for profit. Yet insurers are only one – perhaps the most visible – part of that broken system.

Simon F. Haeder, Associate Professor of Public Health, Texas A&M University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Arindam Sau, University of Colorado Boulder; Mihai Popescu, Colorado State University, and Xin Liu, Colorado State University

Perfluoroalkyl and polyfluoroalkyl substances, or PFAS, have earned the nickname of forever chemicals from their extraordinary ability to stick around in the environment long after they’ve been used.

These synthetic compounds, commonly used in consumer products and industrial applications for their water- and grease-resistant properties, are now found practically everywhere in the environment.

While many chemicals will degrade relatively quickly after they’re disposed of, PFAS can stick around for up to 1,000 years. This durability is great for their use in firefighting foams, nonstick cookware, waterproof clothing and even food packaging.

However, their resilience means that they persist in soil, water and even living organisms. They can accumulate over time and affect the health of both ecosystems and humans.

Some initial research has shown potential links between PFAS exposure and various health issues — including cancers, immune system suppression and hormone disruption. These concerns have led scientists to search for effective ways to break down these stubborn chemicals.

We’re a team of researchers who developed a chemical system that uses light to break down bonds between carbon and fluorine atoms. These strong chemical bonds help PFAS resist degradation. We published this work in Nature in November 2024, and we hope this technique could help address the widespread contamination these substances cause.

Why PFAS compounds are so hard to break down

PFAS compounds have carbon-fluorine bonds, one of the strongest in chemistry. These bonds make PFAS incredibly stable. They resist the degradation processes that usually break down industrial chemicals – including hydrolysis, oxidation and microbial breakdown.

Conventional water treatment methods can remove PFAS from water, but these processes merely concentrate the contaminants instead of destroying them. The resulting PFAS-laden materials are typically sent to landfills. Once disposed of, they can still leach back into the environment.

The current methods for breaking carbon-fluorine bonds depend on use of metals and very high temperatures. For example, platinum metal can be used for this purpose. This dependence makes these methods expensive, energy-intensive and challenging to use on a large scale.

How our new photocatalytic system works

The new method our team has developed uses a purely organic photocatalyst. A photocatalyst is a substance that speeds up a chemical reaction using light, without being consumed in the process. Our system harnesses energy from cheap blue LEDs to drive a set of chemical reactions.

After absorbing light, the photocatalyst transfers electrons to the molecules containing fluorine, which breaks down the sturdy carbon-fluorine bonds.

By directly targeting and dismantling the molecular structure of PFAS, photocatalytic systems like ours hold the potential for complete mineralization. Complete mineralization is a process that transforms these harmful chemicals into harmless end products, like hydrocarbons and fluoride ions, which degrade easily in the environment. The degraded products can then be safely reabsorbed by plants.

Potential applications and benefits

One of the most promising aspects of this new photocatalytic system is its simplicity. The setup is essentially a small vial illuminated by two LEDs, with two small fans added to keep it cool during the process. It operates under mild conditions and does not use any metals, which are often hazardous to handle and can sometimes be explosive.

The system’s reliance on light – a readily available and renewable energy source – could make it economically viable and sustainable. As we refine it, we hope that it could one day operate with minimal energy input, outside of the energy powering the light.

This platform can also transform other organic molecules that contain carbon-fluorine bonds into valuable chemicals. For instance, thousands of fluoroarenes are commonly available as industrial chemicals and laboratory reagents. These can be transformed into building blocks for making a variety of other materials, including medicines and everyday products.

Challenges and future directions

While this new system shows potential, challenges remain. Currently, we can degrade PFAS only on a small scale. While our experimental setup is effective, it will require substantial scaling up to tackle the PFAS problem on a larger level. Additionally, large molecules with hundreds of carbon-fluorine bonds, like Teflon, do not dissolve into the solvent we use for these reactions, even at high temperatures.

As a result, the system currently can’t break down these materials, and we need to conduct more research.

We also want to improve the long-term stability of these catalysts. Right now, these organic photocatalysts degrade over time, especially when they’re under constant LED illumination. So, designing catalysts that retain their efficiency over the long term will be essential for practical, large-scale use. Developing methods to regenerate or recycle these catalysts without losing performance will also be key for scaling up this technology.

With our colleagues at the Center for Sustainable Photoredox Catalysis, we plan to keep working on light-driven catalysis, aiming to discover more light-driven reactions that solve practical problems. SuPRCat is a National Science Foundation-funded nonprofit Center for Chemical Innovation. The teams there are working to develop reactions for more sustainable chemical manufacturing.

The end goal is to create a system that can remove PFAS contaminants from drinking water at purification plants, but that’s still a long way off. We’d also like to one day use this technology to clean up PFAS-contaminated soils, making them safe for farming and restoring their role in the environment.

Arindam Sau, Ph.D. Candidate in Chemistry, University of Colorado Boulder; Mihai Popescu, Postdoctoral Associate in Chemistry, Colorado State University, and Xin Liu, Postdoctoral Scholar in Chemistry, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.