HEPA purifiers – HEPA stands for high efficiency particulate air – remove particulate matter from the air. Exposure to particulate matter has been connected to respiratory and cardiovascular illnesses as well as neurological diseases such as Alzheimer’s and Parkinson’s. Environmental health researchers increasingly recommend that people use HEPA air purifiers in their homes to lower their exposure to particulate matter, but few studies have examined whether using them boosts mental function.

We analyzed data from a study of 119 people ages 30 to 74 living in Somerville, Massachusetts. Somerville sits along Interstate 93 and Route 28, two major highways, resulting in relatively high levels of traffic-related air pollution. This makes it an especially good location for testing the health effects of air purifiers.

We randomly assigned participants to one of two groups. One used a HEPA air purifier for one month and then a sham air purifier – which looked and acted like the real thing but did not contain the air-cleaning filter – for one month, with a monthlong break in between. The second group used the real and sham purifiers in reverse order.

After each month, participants took a test that measured different aspects of their mental capacity. The test probed people’s visual memory and motor speed skills by measuring how quickly they could draw lines between sequential numbers, and it tested executive function and mental flexibility by asking them to draw lines between alternating sequential numbers and letters.

We found that participants 40 years and older – about 42% of our sample – on average completed the section testing for mental flexibility and executive function 12% faster after using the HEPA purifier than after using the sham purifier. That was true even when we accounted for factors like differences in the amount of time participants spent indoors, with either filter, as well as how stressful they found the test.

This improvement may seem small, but it is similar to the cognitive benefits that people experience from increasing their daily exercise. While you may not experience a sudden increase in clarity from a 12% boost, preventing cognitive decline is vital for long-term well-being. Even small decreases in cognitive functioning may be associated with a higher risk of death.

Why it matters

Air pollution can negatively affect mental function after just a few hours of exposure. Studies show that air purifiers are effective at reducing particulates, but it’s unclear whether these reductions can prevent cognitive harm from ongoing pollution sources like traffic. Research has been especially lacking in people living near major sources of air pollution, such as highways.

People living near highways or major roadways are exposed to more air pollution and also experience higher rates of air pollution-related diseases. These risks aren’t encountered by all Americans equally: People of color and low-income people are more likely to live near highways or areas with heavy traffic.

Our study shows that HEPA air purifiers may offer meaningful health benefits under these circumstances.

What still isn’t known

Research shows that air pollution begins to affect cognitive function especially strongly around age 40. These effects may become increasingly prominent as people age.

HEPA air purifiers may therefore be especially beneficial for older adults. Our study did not explore this possibility, as fewer than 10 of our 119 participants were over the age of 60.

Also, our participants only used a HEPA air purifier for one month. It’s possible that longer durations of air purification may sustain or even increase the improvement in cognitive function we observed in our study.

Finally, it is unclear exactly how air purifiers improve cognition. Some studies suggest that exposure to particulate matter reduces the amount of the brain’s white matter, which helps brain cells conduct electrical signals and maintains connections between brain regions. The brain regions most harmed by air pollution are the ones that control mental flexibility and executive function, the same domains in which we saw improvements in our study.

We plan to study whether reducing particulate matter by using air purifiers is indeed protecting the brain’s white matter, and whether it could reverse some cognitive decline. We will explore that possibility by studying how levels of molecules called metabolites, which cells produce as they do their jobs, change in response to breathing polluted air and air cleaned by a HEPA filter.

Until now, only a very few have been found in the Antarctic. In a study published in Geophysical Research Letters, I present evidence for hundreds of these quakes in Antarctica between 2010 and 2023, mostly at the ocean end of the Thwaites Glacier – the so-called Doomsday Glacier that could send sea levels rising rapidly if it were to collapse.

A recent discovery

A glacial earthquake is created when tall, thin icebergs fall off the end of a glacier into the ocean.

When these icebergs capsize, they clash violently with the “mother” glacier. The clash generates strong mechanical ground vibrations, or seismic waves, that propagate thousands of kilometres from the origin.

What makes glacial earthquakes unique is that they do not generate any high-frequency seismic waves. These waves play a vital role in the detection and location of typical seismic sources, such as earthquakes, volcanoes and nuclear explosions.

Due to this difference, glacial earthquakes were only discovered relatively recently, despite other seismic sources having been documented routinely for several decades.

Varying with the seasons

Most glacial earthquakes detected so far have been located near the ends of glaciers in Greenland, the largest ice cap in the northern hemisphere.

The Greenland glacial earthquakes are relatively large in magnitude. The largest ones are similar in size to those caused by nuclear tests conducted by North Korea in the past two decades. As such, they have been detected by a high-quality, continuously operating seismic monitoring network worldwide.

The Greenland events vary with the seasons, occurring more often in late summer. They have also become more common in recent decades. The signs may be associated with a faster rate of global warming in the polar regions.

Elusive evidence

Although Antarctica is the largest ice sheet on Earth, direct evidence of glacial earthquakes caused by capsizing icebergs there has been elusive. Most previous attempts to detect Antarctic glacial earthquakes used the worldwide network of seismic detectors.

However, if Antarctic glacial earthquakes are of much lower magnitude than those in Greenland, the global network may not detect them.

In my new study, I used seismic stations in Antarctica itself to look for signs of these quakes. My search turned up more than 360 glacier seismic events, most of which are not yet included in any earthquake catalogue.

The events I detected were in two clusters, near Thwaites and Pine Island glaciers. These glaciers have been the largest sources of sea-level rise from Antarctica.

Earthquakes at the Doomsday Glacier

Thwaites Glacier is sometimes known as the Doomsday Glacier. If it were to collapse completely it would raise global sea levels by 3 metres, and it also has the potential to fall apart rapidly.

About two-thirds of the events I detected – 245 out of 362 – were located near the marine end of Thwaites. Most of these events are likely glacial earthquakes due to capsizing icebergs.

The strongest driver of such events does not appear to be the annual oscillation of warm air temperatures that drives the seasonal behaviour of Greenland glacier earthquakes.

Instead, the most prolific period of glacial earthquakes at Thwaites, between 2018 and 2020, coincides with a period of accelerated flow of the glacier’s ice tongue towards the sea. The ice-tongue speed-up period was independently confirmed by satellite observations.

This speed-up could have been caused by ocean conditions, the effect of which is not yet well understood.

The findings suggest the short-term scale impact of ocean states on the stability of marine-terminating glaciers. This is worth further exploration to assess the potential contribution of the glacier to future sea-level rise.

The second largest cluster of detections occurred near the Pine Island Glacier. However, these were consistently located 60–80 kilometres from the waterfront, so they are not likely to have been caused by capsizing icebergs.

These events remain puzzling and require follow-up research.

What’s next for Antarctic glacial earthquake research

The detection of glacial earthquakes associated with iceberg calving at Thwaites Glacier could help answer several important research questions. These include a fundamental question about the potential instability of the Thwaites Glacier due to the interaction of the ocean, ice and solid ground near where it meets the sea.

Better understanding may hold the key to resolving the current large uncertainty in the projected sea-level rise over the next couple of centuries.

The research, published in the scientific journal Discover Food, was led by Dr. Asaf Tzachor, Founder and Academic Director of the Aviram Sustainability and Climate Program at Reichman University, together with researchers from Iceland, Denmark and Austria. Using advanced biotechnology and carefully controlled light conditions, the team produced carbon-neutral, nutrient-rich Spirulina biomass containing active vitamin B12. According to the researchers, this is the first time biologically active vitamin B12 has been reported in Spirulina.

A Global Vitamin B12 Problem

Vitamin B12 is an essential micronutrient involved in several critical processes in the body, including red blood cell formation and normal nervous system function. More than a billion people worldwide are estimated to have low levels of the vitamin.

For many people, meat and dairy products are important dietary sources of B12. The recommended intake cited by the researchers is 2.4 µg/day. However, producing animal-based foods at the scale required to meet global demand also carries environmental costs, which has driven interest in more sustainable alternatives.

Spirulina blue green algae (Arthrospira platensis) has often been promoted as one such option because it is nutrient dense and can be cultivated with a relatively small environmental footprint. But there has been a major obstacle.

Traditional Spirulina contains much of its B12 in the form of pseudo-vitamin B12. Although chemically similar to the vitamin humans need, this form is not bioavailable to people, meaning the body cannot effectively use it. That limitation has prevented conventional Spirulina from serving as a reliable replacement for animal-sourced vitamin B12.

Using Light to Change Spirulina’s Nutrition

To address that problem, researchers from Reichman University, University of Natural Resources and Life Sciences, Vienna, Ruppin Academic Center, Danish Technological Institute, and MATIS, Iceland, carried out an exploratory study of a biotechnology platform developed by VAXA Technologies in Iceland.

The team examined the system’s engineering design, its inputs (such as energy), and the nutritional composition of the biomass it produced.

A central feature of the technology is photonic management (modified light conditions). By changing the light environment in which Spirulina grows, the researchers were able to encourage production of biologically active vitamin B12.

The cultivated Spirulina also contained other bioactive compounds associated with antioxidant, anti-inflammatory, and immune-boosting properties.

Most notably, the resulting carbon-neutral biomass contained 1.64 µg of active vitamin B12 per 100 grams, compared with 0.7-1.5 μg per 100 grams in beef.

Dr. Asaf Tzachor explains, “the findings demonstrate that photosynthetically controlled Spirulina can produce desirable levels of active vitamin B12, offering a sustainable alternative to traditional animal-source foods.”

Could Spirulina Supply Vitamin B12 at Scale?

The researchers also explored what could happen if the system were expanded far beyond its current scale.

In one scenario, reallocating electricity currently used by heavy industry in Iceland could support production of 277,950 tonnes of Spirulina biomass each year. The researchers estimate that this amount would contain about 4555 grams of active vitamin B12 annually.

According to their calculations, that quantity could provide the recommended dietary allowance (RDA) for more than 13.8 million children aged 1-3.

More ambitious production scenarios could potentially supply enough vitamin B12 to meet the RDA for more than 26.5 million children aged 1-3 and more than 50 million children aged 0-6 months.

These figures are projections based on possible scale-up scenarios rather than existing production levels, but they illustrate the nutritional potential the researchers see in the technology.

A More Sustainable Source of an Essential Vitamin

If the approach can be successfully expanded, photosynthetically controlled Spirulina could provide another route for addressing vitamin B12 deficiency while reducing some dependence on meat and dairy production.

The work also highlights how biotechnology can alter the nutritional properties of microorganisms and other rapidly growing food sources. Rather than simply cultivating conventional Spirulina, researchers are changing the conditions under which it grows to encourage production of specific compounds that are useful to humans.

The findings represent a step toward developing more sustainable sources of essential nutrients, although further research and larger-scale production will be needed to determine how the technology could fit into real-world food systems.

Reichman University and the Aviram Foundation established the Aviram Sustainability and Climate Program in response to growing environmental and public health challenges around the world. The program trains students from a range of disciplines to develop strategies for addressing resource scarcity, climate change, and extreme weather events, as well as food, water, and energy crises.

In a study recently published in The Journals of Gerontology, researchers examined metabolites, small chemicals and molecules created during normal processes in the body. They found that certain combinations of these metabolites were associated with earlier or later death in dogs in ways that closely resembled patterns previously identified in humans.

“The molecules that are risky for dogs or protective against a sooner death are very similar to those in people, showing that we share important features of aging biology, which is really interesting and rewarding,” said Dr. Kate Creevy, chief veterinary officer for the Dog Aging Project and a professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences, where the work of the Dog Aging Project is generously supported by the WoodNext Foundation. “Our findings also highlight the value of pet dogs as a model for studying long-term health and lifespan.”

Searching for Biological Signs of Lifespan

Metabolites can provide a snapshot of what is happening inside cells, making them useful for detecting biological patterns that may be connected to health and aging.

For the study, researchers analyzed blood samples from dogs participating in the Dog Aging Project. This community science effort follows dogs throughout their lives, with owners contributing detailed survey information and, in some cases, physical samples. The research team examined the blood for metabolic patterns associated with lifespan, focusing specifically on whether individual dogs died earlier or later.

“Death is an easy outcome to understand,” Creevy said. “It is very easy to tell when a person or a dog has died, whereas other features of aging health are a bit more nuanced.”

Using mortality as a clear endpoint allows scientists to work backward and investigate which biological processes may have contributed to the outcome. These processes can include metabolism, inflammation and the ways cells react to stress.

“If we understand why something happened, we have a greater chance of identifying ways to change it,” Creevy said.

A Metabolic Fingerprint of Aging

Rather than focusing on individual molecules, the researchers analyzed thousands of metabolites together to look for larger patterns associated with risk. Creevy said these broader groups can reveal more about what may be taking place inside cells than any single molecule alone.

“Some of my colleagues refer to it as a fingerprint,” Creevy said. “We often look at a pattern or grouping that has a relationship with better or worse outcomes rather than just looking at a single molecule.”

These measurable biological indicators, known as biomarkers, can help researchers estimate the likelihood of certain health outcomes by revealing changes occurring inside the body.

“Importantly, those biomarkers do not necessarily cause an outcome; when we find a biomarker associated with sooner or later mortality, we don’t know that it’s causing it,” Creevy said. “But if we understand why that biomarker is present, we may be able to identify what the cause of the relationship is.”

Finding these recurring patterns gives scientists possible starting points for investigating the mechanisms behind aging and, eventually, identifying biological targets that might help improve health over time.

Dogs and Humans Share Similar Aging Signals

The researchers then asked whether the metabolic patterns seen in dogs also appeared in people. To find out, they compared their results with five large published studies of human mortality that used similar methods to examine metabolites.

Across those studies, the signals associated with earlier or later death were broadly similar to those found in dogs.

That consistency was one of the most striking results, adding evidence that dogs and humans share important features of the biology that underlies aging.

“Frequently, we know a little more about this in people than we do in dogs,” Creevy said. “If we have the same targets, we’ll be able to leverage human research to benefit dogs.”

The similarities could allow scientists to use knowledge already gained from human research to improve canine health, while also using dogs to study how aging develops across an entire lifespan.

Why Dogs Are Valuable for Aging Research

Pet dogs offer several advantages for researchers studying aging. They share many parts of everyday life with humans, including their surroundings, diets and activity patterns. That overlap gives scientists an opportunity to examine how lifestyle and environment affect long-term health.

“One of the things we like most about learning from dogs as it pertains to aging is their widely varied lifestyles that mirror their owners’ lifestyles in a way that’s less true for other companion animals,” Creevy said.

Cats, for example, often live more independent and relatively consistent lifestyles. Dogs are more likely to follow the routines, environments and activity patterns of the people they live with.

Their shorter lifespans provide another major advantage. Humans, on average, live into their 70s, while dogs typically live only 12-13 years. That difference allows researchers to observe aging and lifespan outcomes in dogs much more quickly than would be possible in human studies.

Inside the Dog Aging Project

The research was made possible by the Dog Aging Project, a nationwide, long-term study that follows pet dogs living with owners across the United States.

Owners who participate provide extensive information about their dogs’ lives, while a subset also submit biological samples each year. Together, those contributions allow researchers to track changes in health and aging over time.

“The owners who enroll their dogs make everything possible,” Creevy said. “The dedication and commitment of these owners to participate in research and discovery to better the health of dogs is remarkable.”

Creevy said the latest findings are an early but important step toward understanding the mechanisms that influence aging. Researchers have now identified metabolic patterns associated with lifespan, giving them specific biological signals to investigate further.

“This is a starting point,” she said. “We’ve identified these metabolites, and now we know where to start looking.”

For people who own dogs, Creevy said the practical message is straightforward. Many of the same behaviors that promote healthier aging in people are also likely to benefit dogs.

“Keeping them on a healthy diet, at a healthy body weight, and preserving mobility and cognitive health — just like we would do for ourselves,” Creevy said. “What’s good for us is probably good for them.”

The findings do not prove that melatonin itself caused the increased risks. However, they raise new questions about the long-term safety of a supplement that many people view as a harmless or “natural” way to improve sleep.

Why Melatonin Is So Widely Used

Melatonin is a hormone made naturally by the pineal gland in the brain. It helps control the body’s sleep and wake cycle, also known as the circadian rhythm. Levels of the hormone typically rise when it gets dark and fall during daylight.

Synthetic melatonin is chemically identical to the hormone produced by the body. It is commonly used for insomnia (difficulty falling and/or staying asleep) and jet lag.

Melatonin supplements are available over the counter in many countries, including the U.S. In the U.S., over-the-counter supplements are not regulated, so each brand of supplement can vary in strength, purity, etc.

For the new study, researchers divided participants according to their documented melatonin use. People with at least one year of melatonin use recorded in their electronic medical records were placed in the “melatonin group.” Those with no record of melatonin use anywhere in their medical records were assigned to the “non-melatonin group.”

“Melatonin supplements may not be as harmless as commonly assumed. If our study is confirmed, this could affect how doctors counsel patients about sleep aids,” said Ekenedilichukwu Nnadi, M.D., lead author of the study and chief resident in internal medicine at SUNY Downstate/Kings County Primary Care in Brooklyn, New York.

Researchers Looked for Long-Term Heart Risks

Melatonin is often promoted as a safe sleep aid, but researchers say there is limited evidence about its cardiovascular safety when taken for extended periods.

That uncertainty led the team to investigate whether long-term melatonin use might be associated with heart failure among people who already had chronic insomnia.

Heart failure does not mean that the heart has completely stopped working. It develops when the heart cannot pump enough oxygen-rich blood to meet the body’s needs. According to the American Heart Association’s 2025 Heart Disease and Stroke Statistics, the condition affects about 6.7 million adults in the U.S.

Researchers used data from the TriNetX Global Research Network, a large international database containing de-identified electronic health records.

They examined five years of medical records for adults with chronic insomnia whose records showed melatonin use for more than a year. Those participants were matched with other people who also had insomnia but had no documented melatonin use.

Anyone who had already been diagnosed with heart failure or who had been prescribed other sleep medications was excluded.

Heart Failure Risk Was About 90% Higher

The main analysis found a substantial difference between the two groups.

Among adults with insomnia, people with documented long-term melatonin use (12 months or more) had about a 90% higher chance of developing heart failure during the following five years compared with matched nonusers. Heart failure occurred in 4.6% of the melatonin group compared with 2.7% of the comparison group.

Researchers then performed another analysis designed to strengthen confidence that participants had actually been using melatonin over an extended period.

When they limited the analysis to people who had filled at least two melatonin prescriptions at least 90 days apart, the association remained. That group had an 82% higher risk of heart failure. (Melatonin is only available by prescription in the United Kingdom.)

Hospitalization and Death Were Also Higher

A secondary analysis found even larger differences in some outcomes.

People in the melatonin group were nearly 3.5 times as likely to be hospitalized for heart failure as those in the comparison group. The hospitalization rates were 19.0% and 6.6%, respectively.

Deaths from any cause were also more common among people with documented melatonin use. During the five-year period, 7.8% of participants in the melatonin group died compared with 4.3% of those in the non-melatonin group, making the risk nearly twice as high.

“Melatonin supplements are widely thought of as a safe and ‘natural’ option to support better sleep, so it was striking to see such consistent and significant increases in serious health outcomes, even after balancing for many other risk factors,” Nnadi said.

The results also drew concern from sleep researcher Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, who was not involved in the study.

“I’m surprised that physicians would prescribe melatonin for insomnia and have patients use it for more than 365 days, since melatonin, at least in the U.S., is not indicated for the treatment of insomnia. In the U.S., melatonin can be taken as an over-the-counter supplement and people should be aware that it should not be taken chronically without a proper indication,” said Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, chair of the writing group for the American Heart Association’s 2025 scientific statement, Multidimensional Sleep Health: Definitions and Implications for Cardiometabolic Health.

St-Onge is a professor of nutritional medicine in the division of general medicine and director of the Center of Excellence for Sleep & Circadian Research in the department of medicine at Columbia University Irving Medical Center in New York City.

Important Limitations Complicate the Findings

The study comes with several significant limitations, particularly because melatonin is handled differently from one country to another.

Some countries, such as the United Kingdom, require a prescription for melatonin, while others, including the United States, allow people to buy it over the counter. Researchers did not have access to participants’ locations because the medical data had been de-identified.

Melatonin use was identified only when it appeared in electronic medical records. That means people in the U.S. or other countries who bought melatonin over the counter without having it entered into their medical records could have been incorrectly classified as nonusers.

As a result, the melatonin and nonmelatonin groups may not perfectly reflect who was actually taking the supplement.

There was another complication involving hospitalizations. The number of heart failure-related hospitalizations was higher than the number of newly diagnosed heart failure cases because hospitals may enter a variety of related diagnostic codes. Those records do not always include a code specifically identifying a new heart failure diagnosis.

Researchers also did not have information about how severe each participant’s insomnia was or whether participants had other psychiatric disorders.

Those missing factors are important because people with more severe insomnia, depression, anxiety, or other conditions may be more likely to use melatonin and could independently have a different cardiovascular risk.

“Worse insomnia, depression/anxiety, or the use of other sleep-enhancing medicines might be linked to both melatonin use and heart risk,” Nnadi said. “Also, while the association we found raises safety concerns about the widely used supplement, our study cannot prove a direct cause-and-effect relationship. This means more research is needed to test melatonin’s safety for the heart.”

What the Study Included

• The analysis included 130,828 adults (average age of 55.7 years; 61.4% women) who had been diagnosed with insomnia.
• The data came from TriNetX, established in 2013, a growing global network of real-world, de-identified patient information used for medical research.
• Of the participants, 65,414 had been prescribed melatonin at least once and reported using it for at least one year.
• Researchers also created a comparison group (control group) made up of people who had never been prescribed melatonin. These participants were matched to the melatonin group using 40 factors, including demographic characteristics, existing health conditions, and medications.
• Anyone who had already been diagnosed with heart failure was excluded, as were people who had been prescribed other kinds of sleeping pills such as benzodiazepines.
• The melatonin and comparison groups were matched for age, sex, race/ethnicity, heart and nervous system diseases, medications for heart and nervous system diseases, blood pressure, and body mass index.
• Researchers then examined electronic medical records covering the five years after the groups were matched.
• For the primary analysis, they searched for medical codes indicating an initial diagnosis of heart failure. Secondary outcomes included codes associated with hospitalization for heart failure or death.
• The researchers also carried out what is known as a sensitivity analysis, a method used to check whether results remain similar when the study criteria are changed slightly.
• For this additional test, participants in the melatonin group had to have filled at least two melatonin prescriptions at least 90 days apart. The association with higher heart failure risk remained, providing an additional check on the original findings.
• Even so, the researchers emphasize that the study was observational. It identified an association between long-term documented melatonin use and serious health outcomes, but it cannot establish that melatonin directly caused those outcomes. Further research will be needed to determine whether long-term melatonin use itself affects cardiovascular health and, if so, why.

The findings suggest that the region’s geology could eventually support a new domestic energy source and, if developed at scale, a major hydrogen export industry.

Magnetite Could Generate Hydrogen Underground

The research focuses on magnetite, a mineral that is abundant in Western Australia’s huge iron ore deposits across the Pilbara region.

Scientists from ECU’s School of Engineering found that magnetite can release hydrogen gas when it reacts with hot water under conditions similar to those deep below the Earth’s surface.

The team also discovered a way to stimulate the process. By injecting a solution into banded iron formations, the researchers were able to increase hydrogen generation, raising the possibility that naturally produced hydrogen could one day be deliberately enhanced underground.

“Australia could be sitting on a massive, untapped energy reserve — and the potential is enormous,” Associate Professor Alireza Keshavarz said.

“There is enough hydrogen for Australia to benefit for generations, and potentially enough for us to become a major exporter of clean energy to the rest of the world.”

Recreating Deep Underground Conditions

To investigate how the process works, the researchers placed magnetite samples in water at 200°C under high pressure for 60 days. Those conditions were designed to reproduce the hot, pressurized environment found deep underground.

The experiments gave researchers a clearer picture of how natural hydrogen can form within rock and what conditions are needed for production to continue over time.

The findings are especially significant for Western Australia because the region contains some of the largest banded iron formations on Earth.

“Western Australia has some of the world’s largest banded iron formations. If we can unlock this resource at scale, it could be transformative for our energy future,” lead author Kaveh Moghanirahimi said.

“We even see the potential for Western Australia to strengthen its energy independence during times of crisis through access to this naturally generated hydrogen.”

From Laboratory Experiments to Natural Hydrogen Exploration

Professor Stefan Iglauer, from ECU’s School of Engineering, said the results bring researchers closer to understanding how hydrogen production might work in real underground rock formations rather than only in controlled laboratory settings.

“This work helps bridge the gap between laboratory experiments and real geological systems,” Professor Iglauer said.

The study also found that the amount of magnetite alone does not determine how much hydrogen can be produced. The structure of the rock matters as well, particularly whether water can move through it and reach fresh mineral surfaces.

“Our findings show that hydrogen production depends not only on the amount of magnetite present, but also on how easily water can access fresh mineral surfaces through fractures, pores and permeable pathways.”

That means fractures, pores, and other pathways through the rock could play a critical role in determining whether natural hydrogen can be generated efficiently enough to become a practical energy resource.

The research, Geometry-driven controls on hydrothermal natural hydrogen generation from magnetite mineral, has been published in the International Journal of Hydrogen Energy.