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    Study: Climate change may make it harder to reduce smog in some regions

    Global warming will likely hinder our future ability to control ground-level ozone, a harmful air pollutant that is a primary component of smog, according to a new MIT study.The results could help scientists and policymakers develop more effective strategies for improving both air quality and human health. Ground-level ozone causes a host of detrimental health impacts, from asthma to heart disease, and contributes to thousands of premature deaths each year.The researchers’ modeling approach reveals that, as the Earth warms due to climate change, ground-level ozone will become less sensitive to reductions in nitrogen oxide emissions in eastern North America and Western Europe. In other words, it will take greater nitrogen oxide emission reductions to get the same air quality benefits.However, the study also shows that the opposite would be true in northeast Asia, where cutting emissions would have a greater impact on reducing ground-level ozone in the future. The researchers combined a climate model that simulates meteorological factors, such as temperature and wind speeds, with a chemical transport model that estimates the movement and composition of chemicals in the atmosphere.By generating a range of possible future outcomes, the researchers’ ensemble approach better captures inherent climate variability, allowing them to paint a fuller picture than many previous studies.“Future air quality planning should consider how climate change affects the chemistry of air pollution. We may need steeper cuts in nitrogen oxide emissions to achieve the same air quality goals,” says Emmie Le Roy, a graduate student in the MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS) and lead author of a paper on this study.Her co-authors include Anthony Y.H. Wong, a postdoc in the MIT Center for Sustainability Science and Strategy; Sebastian D. Eastham, principal research scientist in the MIT Center for Sustainability Science and Strategy; Arlene Fiore, the Peter H. Stone and Paola Malanotte Stone Professor of EAPS; and senior author Noelle Selin, a professor in the Institute for Data, Systems, and Society (IDSS) and EAPS. The research appears today in Environmental Science and Technology.Controlling ozoneGround-level ozone differs from the stratospheric ozone layer that protects the Earth from harmful UV radiation. It is a respiratory irritant that is harmful to the health of humans, animals, and plants.Controlling ground-level ozone is particularly challenging because it is a secondary pollutant, formed in the atmosphere by complex reactions involving nitrogen oxides and volatile organic compounds in the presence of sunlight.“That is why you tend to have higher ozone days when it is warm and sunny,” Le Roy explains.Regulators typically try to reduce ground-level ozone by cutting nitrogen oxide emissions from industrial processes. But it is difficult to predict the effects of those policies because ground-level ozone interacts with nitrogen oxide and volatile organic compounds in nonlinear ways.Depending on the chemical environment, reducing nitrogen oxide emissions could cause ground-level ozone to increase instead.“Past research has focused on the role of emissions in forming ozone, but the influence of meteorology is a really important part of Emmie’s work,” Selin says.To conduct their study, the researchers combined a global atmospheric chemistry model with a climate model that simulate future meteorology.They used the climate model to generate meteorological inputs for each future year in their study, simulating factors such as likely temperature and wind speeds, in a way that captures the inherent variability of a region’s climate.Then they fed those inputs to the atmospheric chemistry model, which calculates how the chemical composition of the atmosphere would change because of meteorology and emissions.The researchers focused on Eastern North America, Western Europe, and Northeast China, since those regions have historically high levels of the precursor chemicals that form ozone and well-established monitoring networks to provide data.They chose to model two future scenarios, one with high warming and one with low warming, over a 16-year period between 2080 and 2095. They compared them to a historical scenario capturing 2000 to 2015 to see the effects of a 10 percent reduction in nitrogen oxide emissions.Capturing climate variability“The biggest challenge is that the climate naturally varies from year to year. So, if you want to isolate the effects of climate change, you need to simulate enough years to see past that natural variability,” Le Roy says.They could overcome that challenge due to recent advances in atmospheric chemistry modeling and by taking advantage of parallel computing to simulate multiple years at the same time. They simulated five 16-year realizations, resulting in 80 model years for each scenario.The researchers found that eastern North America and Western Europe are especially sensitive to increases in nitrogen oxide emissions from the soil, which are natural emissions driven by increases in temperature.Due to that sensitivity, as the Earth warms and more nitrogen oxide from soil enters the atmosphere, reducing nitrogen oxide emissions from human activities will have less of an impact on ground-level ozone.“This shows how important it is to improve our representation of the biosphere in these models to better understand how climate change may impact air quality,” Le Roy says.On the other hand, since industrial processes in northeast Asia cause more ozone per unit of nitrogen oxide emitted, cutting emissions there would cause greater reductions in ground-level ozone in future warming scenarios.“But I wouldn’t say that is a good thing because it means that, overall, there are higher levels of ozone,” Le Roy adds.Running detailed meteorology simulations, rather than relying on annual average weather data, gave the researchers a more complete picture of the potential effects on human health.“Average climate isn’t the only thing that matters. One high ozone day, which might be a statistical anomaly, could mean we don’t meet our air quality target and have negative human health impacts that we should care about,” Le Roy says.In the future, the researchers want to continue exploring the intersection of meteorology and air quality. They also want to expand their modeling approach to consider other climate change factors with high variability, like wildfires or biomass burning.“We’ve shown that it is important for air quality scientists to consider the full range of climate variability, even if it is hard to do in your models, because it really does affect the answer that you get,” says Selin.This work is funded, in part, by the MIT Praecis Presidential Fellowship, the J.H. and E.V. Wade Fellowship, and the MIT Martin Family Society of Fellows for Sustainability. More

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    Imaging technique removes the effect of water in underwater scenes

    The ocean is teeming with life. But unless you get up close, much of the marine world can easily remain unseen. That’s because water itself can act as an effective cloak: Light that shines through the ocean can bend, scatter, and quickly fade as it travels through the dense medium of water and reflects off the persistent haze of ocean particles. This makes it extremely challenging to capture the true color of objects in the ocean without imaging them at close range.Now a team from MIT and the Woods Hole Oceanographic Institution (WHOI) has developed an image-analysis tool that cuts through the ocean’s optical effects and generates images of underwater environments that look as if the water had been drained away, revealing an ocean scene’s true colors. The team paired the color-correcting tool with a computational model that converts images of a scene into a three-dimensional underwater “world,” that can then be explored virtually.The researchers have dubbed the new tool “SeaSplat,” in reference to both its underwater application and a method known as 3D gaussian splatting (3DGS), which takes images of a scene and stitches them together to generate a complete, three-dimensional representation that can be viewed in detail, from any perspective.“With SeaSplat, it can model explicitly what the water is doing, and as a result it can in some ways remove the water, and produces better 3D models of an underwater scene,” says MIT graduate student Daniel Yang.The researchers applied SeaSplat to images of the sea floor taken by divers and underwater vehicles, in various locations including the U.S. Virgin Islands. The method generated 3D “worlds” from the images that were truer and more vivid and varied in color, compared to previous methods.The team says SeaSplat could help marine biologists monitor the health of certain ocean communities. For instance, as an underwater robot explores and takes pictures of a coral reef, SeaSplat would simultaneously process the images and render a true-color, 3D representation, that scientists could then virtually “fly” through, at their own pace and path, to inspect the underwater scene, for instance for signs of coral bleaching.“Bleaching looks white from close up, but could appear blue and hazy from far away, and you might not be able to detect it,” says Yogesh Girdhar, an associate scientist at WHOI. “Coral bleaching, and different coral species, could be easier to detect with SeaSplat imagery, to get the true colors in the ocean.”Girdhar and Yang will present a paper detailing SeaSplat at the IEEE International Conference on Robotics and Automation (ICRA). Their study co-author is John Leonard, professor of mechanical engineering at MIT.Aquatic opticsIn the ocean, the color and clarity of objects is distorted by the effects of light traveling through water. In recent years, researchers have developed color-correcting tools that aim to reproduce the true colors in the ocean. These efforts involved adapting tools that were developed originally for environments out of water, for instance to reveal the true color of features in foggy conditions. One recent work accurately reproduces true colors in the ocean, with an algorithm named “Sea-Thru,” though this method requires a huge amount of computational power, which makes its use in producing 3D scene models challenging.In parallel, others have made advances in 3D gaussian splatting, with tools that seamlessly stitch images of a scene together, and intelligently fill in any gaps to create a whole, 3D version of the scene. These 3D worlds enable “novel view synthesis,” meaning that someone can view the generated 3D scene, not just from the perspective of the original images, but from any angle and distance.But 3DGS has only successfully been applied to environments out of water. Efforts to adapt 3D reconstruction to underwater imagery have been hampered, mainly by two optical underwater effects: backscatter and attenuation. Backscatter occurs when light reflects off of tiny particles in the ocean, creating a veil-like haze. Attenuation is the phenomenon by which light of certain wavelengths attenuates, or fades with distance. In the ocean, for instance, red objects appear to fade more than blue objects when viewed from farther away.Out of water, the color of objects appears more or less the same regardless of the angle or distance from which they are viewed. In water, however, color can quickly change and fade depending on one’s perspective. When 3DGS methods attempt to stitch underwater images into a cohesive 3D whole, they are unable to resolve objects due to aquatic backscatter and attenuation effects that distort the color of objects at different angles.“One dream of underwater robotic vision that we have is: Imagine if you could remove all the water in the ocean. What would you see?” Leonard says.A model swimIn their new work, Yang and his colleagues developed a color-correcting algorithm that accounts for the optical effects of backscatter and attenuation. The algorithm determines the degree to which every pixel in an image must have been distorted by backscatter and attenuation effects, and then essentially takes away those aquatic effects, and computes what the pixel’s true color must be.Yang then worked the color-correcting algorithm into a 3D gaussian splatting model to create SeaSplat, which can quickly analyze underwater images of a scene and generate a true-color, 3D virtual version of the same scene that can be explored in detail from any angle and distance.The team applied SeaSplat to multiple underwater scenes, including images taken in the Red Sea, in the Carribean off the coast of Curaçao, and the Pacific Ocean, near Panama. These images, which the team took from a pre-existing dataset, represent a range of ocean locations and water conditions. They also tested SeaSplat on images taken by a remote-controlled underwater robot in the U.S. Virgin Islands.From the images of each ocean scene, SeaSplat generated a true-color 3D world that the researchers were able to virtually explore, for instance zooming in and out of a scene and viewing certain features from different perspectives. Even when viewing from different angles and distances, they found objects in every scene retained their true color, rather than fading as they would if viewed through the actual ocean.“Once it generates a 3D model, a scientist can just ‘swim’ through the model as though they are scuba-diving, and look at things in high detail, with real color,” Yang says.For now, the method requires hefty computing resources in the form of a desktop computer that would be too bulky to carry aboard an underwater robot. Still, SeaSplat could work for tethered operations, where a vehicle, tied to a ship, can explore and take images that can be sent up to a ship’s computer.“This is the first approach that can very quickly build high-quality 3D models with accurate colors, underwater, and it can create them and render them fast,” Girdhar says. “That will help to quantify biodiversity, and assess the health of coral reef and other marine communities.”This work was supported, in part, by the Investment in Science Fund at WHOI, and by the U.S. National Science Foundation. More

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    A day in the life of MIT MBA student David Brown

    “MIT Sloan was my first and only choice,” says MIT graduate student David Brown. After receiving his BS in chemical engineering at the U.S. Military Academy at West Point, Brown spent eight years as a helicopter pilot in the U.S. Army, serving as a platoon leader and troop commander. Now in the final year of his MBA, Brown has co-founded a climate tech company — Helix Carbon — with Ariel Furst, an MIT assistant professor in the Department of Chemical Engineering, and Evan Haas MBA ’24, SM ’24. Their goal: erase the carbon footprint of tough-to-decarbonize industries like ironmaking, polyurethanes, and olefins by generating competitively-priced, carbon-neutral fuels directly from waste carbon dioxide (CO2). It’s an ambitious project; they’re looking to scale the company large enough to have a gigaton per year impact on CO2 emissions. They have lab space off campus, and after graduation, Brown will be taking a full-time job as chief operating officer.“What I loved about the Army was that I felt every day that the work I was doing was important or impactful in some way. I wanted that to continue, and felt the best way to have the greatest possible positive impact was to use my operational skills learned from the military to help close the gap between the lab and impact in the market.”The following photo essay provides a snapshot of what a typical day for Brown has been like as an MIT student.

    8:30 a.m. — “The first thing on my schedule today is meeting with the Helix Carbon team. Today, we’re talking about the results from the latest lab runs, and what they mean for planned experiments the rest of the week. We are also discussing our fundraising plans ahead of the investor meetings we have scheduled for later this week.”

    10:00 a.m. — “I spend a lot of time at the Martin Trust Center for MIT Entrepreneurship. It’s the hub of entrepreneurship at MIT. My pre-MBA internship, and my first work experience after leaving the Army, was as the program manager for delta v, the premier startup accelerator at MIT. That was also my introduction to the entrepreneurship ecosystem at MIT, and how I met Ariel. With zero hyperbole I can say that was a life-changing experience, and really defined the direction of my life out of the military.”

    10:30 a.m. — “In addition to working to fund and scale Helix Carbon, I have a lot of work to do to finish up the semester. Something I think is unique about MIT is that classes give a real-world perspective from people who are actively a participant on the cutting edge of what’s happening in that realm. For example, I’m taking Climate and Energy in the Global Economy, and the professor, Catherine Wolfram, has incredible experience both on the ground and in policy with both climate and energy.”

    11:00 a.m. — “When I arrived at MIT Sloan, I was grouped into my cohort team. We navigated the first semester core classes together and built a strong bond. We still meet up for coffee and have team dinners even a year-and-a-half later. I always find myself inspired by how much they’ve accomplished, and I consider myself incredibly lucky for their support and to call them my friends.”

    12 p.m. — “Next, I have a meeting with Bill Aulet, the managing director of the Trust Center, to prepare for an entrepreneurship accelerator called Third Derivative that Helix Carbon got picked up for. Sustainability startups from all over the U.S. and around the world come together to meet with each other and other mentors in order to share progress, best practices, and develop plans for moving forward.”

    12:30 p.m. — “Throughout the day, I run into friends, colleagues, and mentors. Even though MIT Sloan is pitched as a community experience, I didn’t expect how much of a community experience it really is. My classmates have been the absolute highlight of my time here, and I have learned so much from their experiences and from the way they carry themselves.”

    1 p.m. — “My only class today is Applied Behavioral Economics. I’m taking it almost entirely for pleasure — it’s such a fascinating topic. And the professor — Drazen Prelec — is one of the world’s foremost experts. It’s a class that challenges assumptions and gets me thinking. I really enjoy it.”

    2:30 p.m. — “I have a little bit of time before my next event. When I need a place that isn’t too crowded to think, I like to hang out on the couch on the sky bridge between the Tang Center and the Morris and Sophie Chang Building. When the weather is nice, I’ll head out to one of the open green spaces in Kendall Square, or to Urban Park across the street.”

    3:30 p.m. — “When I was the program manager for delta v, this was where I sat, and it’s still where I like to spend time when I’m at the Trust Center. Because it looks like a welcome desk, a lot of people come up to ask questions or talk about their startups. Since I used to work there I’m able to help them out pretty well!”

    5:00 p.m. — “For my last event of the day, I’m attending a seminar at the Priscilla King Gray Public Service Center (PKG Center) as part of their IDEAS Social Innovation Challenge, MIT’s 20-plus year-old social impact incubator. The program works with MIT student-led teams addressing social and environmental challenges in our communities. The program has helped teach us critical frameworks and tools around setting goals for and measuring our social impact. We actually placed first in the Harvard Social Enterprise Conference Pitch competition thanks to the lessons we learned here!”

    7:00 p.m. — “Time to head home. A few days a week after work and class, my wife and I play in a combat archery league. It’s like dodgeball, but instead of dodgeballs everyone has a bow and you shoot arrows that have pillow tips. It’s incredible. Tons of fun. I have tried to recruit many of my classmates — marginal success rate!”

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    How J-WAFS Solutions grants bring research to market

    For the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), 2025 marks a decade of translating groundbreaking research into tangible solutions for global challenges. Few examples illustrate that mission better than NONA Technologies. With support from a J-WAFS Solutions grant, MIT electrical engineering and biological engineering Professor Jongyoon Han and his team developed a portable desalination device that transforms seawater into clean drinking water without filters or high-pressure pumps. The device stands apart from traditional systems because conventional desalination technologies, like reverse osmosis, are energy-intensive, prone to fouling, and typically deployed at large, centralized plants. In contrast, the device developed in Han’s lab employs ion concentration polarization technology to remove salts and particles from seawater, producing potable water that exceeds World Health Organization standards. It is compact, solar-powered, and operable at the push of a button — making it an ideal solution for off-grid and disaster-stricken areas.This research laid the foundation for spinning out NONA Technologies along with co-founders Junghyo Yoon PhD ’21 from Han’s lab and Bruce Crawford MBA ’22, to commercialize the technology and address pressing water-scarcity issues worldwide. “This is really the culmination of a 10-year journey that I and my group have been on,” said Han in an earlier MIT News article. “We worked for years on the physics behind individual desalination processes, but pushing all those advances into a box, building a system, and demonstrating it in the ocean … that was a really meaningful and rewarding experience for me.” You can watch this video showcasing the device in action.Moving breakthrough research out of the lab and into the world is a well-known challenge. While traditional “seed” grants typically support early-stage research at Technology Readiness Level (TRL) 1-2, few funding sources exist to help academic teams navigate to the next phase of technology development. The J-WAFS Solutions Program is strategically designed to address this critical gap by supporting technologies in the high-risk, early-commercialization phase that is often neglected by traditional research, corporate, and venture funding. By supporting technologies at TRLs 3-5, the program increases the likelihood that promising innovations will survive beyond the university setting, advancing sufficiently to attract follow-on funding.Equally important, the program gives academic researchers the time, resources, and flexibility to de-risk their technology, explore customer need and potential real-world applications, and determine whether and how they want to pursue commercialization. For faculty-led teams like Han’s, the J-WAFS Solutions Program provided the critical financial runway and entrepreneurial guidance needed to refine the technology, test assumptions about market fit, and lay the foundation for a startup team. While still in the MIT innovation ecosystem, Nona secured over $200,000 in non-dilutive funding through competitions and accelerators, including the prestigious MIT delta v Educational Accelerator. These early wins laid the groundwork for further investment and technical advancement.Since spinning out of MIT, NONA has made major strides in both technology development and business viability. What started as a device capable of producing just over half-a-liter of clean drinking water per hour has evolved into a system that now delivers 10 times that capacity, at 5 liters per hour. The company successfully raised a $3.5 million seed round to advance its portable desalination device, and entered into a collaboration with the U.S. Army Natick Soldier Systems Center, where it co-developed early prototypes and began generating revenue while validating the technology. Most recently, NONA was awarded two SBIR Phase I grants totaling $575,000, one from the National Science Foundation and another from the National Institute of Environmental Health Sciences.Now operating out of Greentown Labs in Somerville, Massachusetts, NONA has grown to a dedicated team of five and is preparing to launch its nona5 product later this year, with a wait list of over 1,000 customers. It is also kicking off its first industrial pilot, marking a key step toward commercial scale-up. “Starting a business as a postdoc was challenging, especially with limited funding and industry knowledge,” says Yoon, who currently serves as CTO of NONA. “J-WAFS gave me the financial freedom to pursue my venture, and the mentorship pushed me to hit key milestones. Thanks to J-WAFS, I successfully transitioned from an academic researcher to an entrepreneur in the water industry.”NONA is one of several J-WAFS-funded technologies that have moved from the lab to market, part of a growing portfolio of water and food solutions advancing through MIT’s innovation pipeline. As J-WAFS marks a decade of catalyzing innovation in water and food, NONA exemplifies what is possible when mission-driven research is paired with targeted early-stage support and mentorship.To learn more or get involved in supporting startups through the J-WAFS Solutions Program, please contact jwafs@mit.edu. More

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    Startup helps farmers grow plant-based feed and fertilizer using wastewater

    Farmers today face a number of challenges, from supply chain stability to nutrient and waste management. But hanging over everything is the need to maintain profitability amid changing markets and increased uncertainty.Fyto, founded by former MIT staff member Jason Prapas, is offering a highly automated cultivation system to address several of farmers’ biggest problems at once.At the heart of Fyto’s system is Lemna, a genus of small aquatic plants otherwise known as duckweed. Most people have probably seen thick green mats of Lemna lying on top of ponds and swamps. But Lemna is also rich in protein and capable of doubling in biomass every two days. Fyto has built an automated cropping system that uses nitrogen-rich wastewater from dairy farms to grow Lemna in shallow pools on otherwise less productive farmland. On top of the pools, the company has built what it believes are the largest agricultural robots in the world, which monitor plant health and harvest the Lemna sustainably. The Lemna can then be used on farms as a high-protein cattle feed or fertilizer supplement.Fyto’s systems are designed to rely on minimal land, water, and labor while creating a more sustainable, profitable food system.“We developed from scratch a robotic system that takes the guesswork out of farming this crop,” says Prapas, who previously led the translational research program of MIT’s Tata Center. “It looks at the crop on a daily basis, takes inventory to know how many plants there are, how much should be harvested to have healthy growth the next day, can detect if the color is slightly off or there are nutrient deficiencies, and can suggest different interventions based on all that data.”From kiddie pools to cow farmsPrapas’ first job out of college was with an MIT spinout called Green Fuel that harvested algae to make biofuel. He went back to school for a master’s and then a PhD in mechanical engineering, but he continued working with startups. Following his PhD at Colorado State University, he co-founded Factor[e] Ventures to fund and incubate startups focused on improving energy access in emerging markets.Through that work, Prapas was introduced to MIT’s Tata Center for Technology and Design.“We were really interested in the new technologies being developed at the MIT Tata Center, and in funding new startups taking on some of these global climate challenges in emerging markets,” Prapas recalls. “The Tata Center was interested in making sure these technologies get put into practice rather than patented and put on a shelf somewhere. It was a good synergy.”One of the people Prapas got to know was Rob Stoner, the founding director of the Tata Center, who encouraged Prapas to get more directly involved with commercializing new technologies. In 2017, Prapas joined the Tata Center as the translational research director. During that time, Prapas worked with MIT students, faculty, and staff to test their inventions in the real world. Much of that work involved innovations in agriculture.“Farming is a fact of life for a lot of folks around the world — both subsistence farming but also producing food for the community and beyond,” Prapas says. “That has huge implications for water usage, electricity consumption, labor. For years, I’d been thinking about how we make farming a more attractive endeavor for people: How do we make it less back-breaking, more efficient, and more economical?”Between his work at MIT and Factor[e], Prapas visited hundreds of farms around the world, where he started to think about the lack of good choices for farming inputs like animal feed and fertilizers. The problem represented a business opportunity.Fyto began with kiddie pools. Prapas started growing aquatic plants in his backyard, using them as a fertilizer source for vegetables. The experience taught him how difficult it would be to train people to grow and harvest Lemna at large scales on farms.“I realized we’d have to invent both the farming method — the agronomy — and the equipment and processes to grow it at scale cost effectively,” Prapas explains.Prapas started discussing his ideas with others around 2019.“The MIT and Boston ecosystems are great for pitching somewhat crazy ideas to willing audiences and seeing what sticks,” Prapas says. “There’s an intangible benefit of being at MIT, where you just can’t help but think of bold ideas and try putting them into practice.”Prapas, who left MIT to lead Fyto in 2019, partnered with Valerie Peng ’17, SM ’19, then a graduate student at MIT who became his first hire.“Farmers work so hard, and I have so much respect for what they do,” says Peng, who serves as Fyto’s head of engineering. “People talk about the political divide, but there’s a lot of alignment around using less, doing more with what you have, and making our food systems more resilient to drought, supply chain disruptions, and everything else. There’s more in common with everyone than you’d expect.”A new farming methodLemna can produce much more protein per acre than soy, another common source of protein on farms, but it requires a lot of nitrogen to grow. Fortunately, many types of farmers, especially large dairy farmers, have abundant nitrogen sources in the waste streams that come from washing out cow manure.“These waste streams are a big problem: In California it’s believed to be one of the largest source of greenhouse gas emissions in the agriculture sector despite the fact that hundreds of crops are grown in California,” Prapas says.For the last few years, Fyto has run its systems in pilots on farms, trialing the crop as feed and fertilizer before delivering to its customers. The systems Fyto has deployed so far are about 50 feet wide, but it is actively commissioning its newest version that’s 160 feet wide. Eventually, Fyto plans to sell the systems directly to farmers.Fyto is currently awaiting California’s approval for use in feed, but Lemna has already been approved in Europe. Fyto has also been granted a fertilizer license on its plant-based fertilizer, with promising early results in trials, and plans to sell new fertilizer products this year.Although Fyto is focused on dairy farms for its early deployments, it has also grown Lemna using manure from chicken, and Prapas notes that even people like cheese producers have a nitrogen waste problem that Fyto could solve.“Think of us like a polishing step you could put on the end of any system that has an organic waste stream,” Prapas says. “In that situation, we’re interested in growing our crops on it. We’ve had very few things that the plant can’t grow on. Globally, we see this as a new farming method, and that means it’s got a lot of potential applications.” More

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    Hundred-year storm tides will occur every few decades in Bangladesh, scientists report

    Tropical cyclones are hurricanes that brew over the tropical ocean and can travel over land, inundating coastal regions. The most extreme cyclones can generate devastating storm tides — seawater that is heightened by the tides and swells onto land, causing catastrophic flood events in coastal regions. A new study by MIT scientists finds that, as the planet warms, the recurrence of destructive storm tides will increase tenfold for one of the hardest-hit regions of the world.In a study appearing today in One Earth, the scientists report that, for the highly populated coastal country of Bangladesh, what was once a 100-year event could now strike every 10 years — or more often — by the end of the century. In a future where fossil fuels continue to burn as they do today, what was once considered a catastrophic, once-in-a-century storm tide will hit Bangladesh, on average, once per decade. And the kind of storm tides that have occurred every decade or so will likely batter the country’s coast more frequently, every few years.Bangladesh is one of the most densely populated countries in the world, with more than 171 million people living in a region roughly the size of New York state. The country has been historically vulnerable to tropical cyclones, as it is a low-lying delta that is easily flooded by storms and experiences a seasonal monsoon. Some of the most destructive floods in the world have occurred in Bangladesh, where it’s been increasingly difficult for agricultural economies to recover.The study also finds that Bangladesh will likely experience tropical cyclones that overlap with the months-long monsoon season. Until now, cyclones and the monsoon have occurred at separate times during the year. But as the planet warms, the scientists’ modeling shows that cyclones will push into the monsoon season, causing back-to-back flooding events across the country.“Bangladesh is very active in preparing for climate hazards and risks, but the problem is, everything they’re doing is more or less based on what they’re seeing in the present climate,” says study co-author Sai Ravela, principal research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “We are now seeing an almost tenfold rise in the recurrence of destructive storm tides almost anywhere you look in Bangladesh. This cannot be ignored. So, we think this is timely, to say they have to pause and revisit how they protect against these storms.”Ravela’s co-authors are Jiangchao Qiu, a postdoc in EAPS, and Kerry Emanuel, professor emeritus of atmospheric science at MIT.Height of tidesIn recent years, Bangladesh has invested significantly in storm preparedness, for instance in improving its early-warning system, fortifying village embankments, and increasing access to community shelters. But such preparations have generally been based on the current frequency of storms.In this new study, the MIT team aimed to provide detailed projections of extreme storm tide hazards, which are flooding events where tidal effects amplify cyclone-induced storm surge, in Bangladesh under various climate-warming scenarios and sea-level rise projections.“A lot of these events happen at night, so tides play a really strong role in how much additional water you might get, depending on what the tide is,” Ravela explains.To evaluate the risk of storm tide, the team first applied a method of physics-based downscaling, which Emanuel’s group first developed over 20 years ago and has been using since to study hurricane activity in different parts of the world. The technique involves a low-resolution model of the global ocean and atmosphere that is embedded with a finer-resolution model that simulates weather patterns as detailed as a single hurricane. The researchers then scatter hurricane “seeds” in a region of interest and run the model forward to observe which seeds grow and make landfall over time.To the downscaled model, the researchers incorporated a hydrodynamical model, which simulates the height of a storm surge, given the pattern and strength of winds at the time of a given storm. For any given simulated storm, the team also tracked the tides, as well as effects of sea level rise, and incorporated this information into a numerical model that calculated the storm tide, or the height of the water, with tidal effects as a storm makes landfall.Extreme overlapWith this framework, the scientists simulated tens of thousands of potential tropical cyclones near Bangladesh, under several future climate scenarios, ranging from one that resembles the current day to one in which the world experiences further warming as a result of continued fossil fuel burning. For each simulation, they recorded the maximum storm tides along the coast of Bangladesh and noted the frequency of storm tides of various heights in a given climate scenario.“We can look at the entire bucket of simulations and see, for this storm tide of say, 3 meters, we saw this many storms, and from that you can figure out the relative frequency of that kind of storm,” Qiu says. “You can then invert that number to a return period.”A return period is the time it takes for a storm of a particular type to make landfall again. A storm that is considered a “100-year event” is typically more powerful and destructive, and in this case, creates more extreme storm tides, and therefore more catastrophic flooding, compared to a 10-year event.From their modeling, Ravela and his colleagues found that under a scenario of increased global warming, the storms that previously were considered 100-year events, producing the highest storm tide values, can recur every decade or less by late-century. They also observed that, toward the end of this century, tropical cyclones in Bangladesh will occur across a broader seasonal window, potentially overlapping in certain years with the seasonal monsoon season.“If the monsoon rain has come in and saturated the soil, a cyclone then comes in and it makes the problem much worse,” Ravela says. “People won’t have any reprieve between the extreme storm and the monsoon. There are so many compound and cascading effects between the two. And this only emerges because warming happens.”Ravela and his colleagues are using their modeling to help experts in Bangladesh better evaluate and prepare for a future of increasing storm risk. And he says that the climate future for Bangladesh is in some ways not unique to this part of the world.“This climate change story that is playing out in Bangladesh in a certain way will be playing out in a different way elsewhere,” Ravela notes. “Maybe where you are, the story is about heat stress, or amplifying droughts, or wildfires. The peril is different. But the underlying catastrophe story is not that different.”This research is supported in part by the MIT Climate Resilience Early Warning Systems Climate Grand Challenges project, the Jameel Observatory JO-CREWSNet project; MIT Weather and Climate Extremes Climate Grand Challenges project; and Schmidt Sciences, LLC.  More

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    MIT students advance solutions for water and food with the help of J-WAFS

    For the past decade, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) has been instrumental in promoting student engagement across the Institute to help solve the world’s most pressing water and food system challenges. As part of J-WAFS’ central mission of securing the world’s water and food supply, J-WAFS aims to cultivate the next generation of leaders in the water and food sectors by encouraging MIT student involvement through a variety of programs and mechanisms that provide research funding, mentorship, and other types of support.J-WAFS offers a range of opportunities for both undergraduate and graduate students to engage in the advancement of water and food systems research. These include graduate student fellowships, travel grants for participation in conferences, funding for research projects in India, video competitions highlighting students’ water and food research, and support for student-led organizations and initiatives focused on critical areas in water and food.As J-WAFS enters its second decade, it continues to expose students across the Institute to experiential hands-on water and food research, career and other networking opportunities, and a platform to develop their innovative and collaborative solutions.Graduate student fellowshipsIn 2017, J-WAFS inaugurated two graduate student fellowships: the Rasikbhai L. Meswani Fellowship for Water Solutions and the J-WAFS Graduate Student Fellowship Program. The Rasikbhai L. Meswani Fellowship for Water Solutions is a doctoral fellowship for students pursuing research related to water for human need at MIT. The fellowship is made possible by Elina and Nikhil Meswani and family. Each year, up to two outstanding students are selected to receive fellowship support for one academic semester. Through it, J-WAFS seeks to support distinguished MIT students who are pursuing solutions to the pressing global water supply challenges of our time. The J-WAFS Fellowship for Water and Food Solutions is funded by the J-WAFS Research Affiliate Program, which offers companies the opportunity to collaborate with MIT on water and food research. A portion of each research affiliate’s fees supports this fellowship.Aditya Avinash Ghodgaonkar, a PhD student in the Department of Mechanical Engineering (MechE), reflects on how receiving a J-WAFS graduate student fellowship positively impacted his research on the design of low-cost emitters for affordable, resilient drip irrigation for farmers: “My J-WAFS fellowship gave me the flexibility and financial support needed to explore new directions in the area of clog-resistant drip irrigation that had a higher risk element that might not have been feasible to manage on an industrially sponsored project,” Ghodgaonkar explains. Emitters, which control the volume and flow rate of water used during irrigation, often clog due to small particles like sand. Ghodgaonkar worked with Professor Amos Winter, and with farmers in resource-constrained communities in countries like Jordan and Morocco, to develop an emitter that is mechanically more resistant to clogging. Ghodgaonkar reports that their energy-efficient, compact, clog-resistant drip emitters are being commercialized by Toro and may be available for retail in the next few years. The opportunities and funding support Ghodgaonkar has received from J-WAFS contributed greatly to his entrepreneurial success and the advancement of the water and agricultural sectors.Linzixuan (Rhoda) Zhang, a PhD student advised by Professor Robert Langer and Principal Research Scientist Ana Jaklenec of the Department of Chemical Engineering, was a 2022 J-WAFS Graduate Student Fellow. With the fellowship, Zhang was able to focus on her innovative research on a novel micronutrient delivery platform that fortifies food with essential vitamins and nutrients. “We intake micronutrients from basically all the healthy food that we eat; however, around the world there are about 2 billion people currently suffering from micronutrient deficiency because they do not have access to very healthy, very fresh food,” Zhang says. Her research involves the development of biodegradable polymers that can deliver these micronutrients in harsh environments in underserved regions of the world. “Vitamin A is not very stable, for example; we have vitamin A in different vegetables but when we cook them, the vitamin can easily degrade,” Zhang explains. However, when vitamin A is encapsulated in the microparticle platform, simulation of boiling and of the stomach environment shows that vitamin A was stabilized. “The meaningful factors behind this experiment are real,” says Zhang. The J-WAFS Fellowship helped position Zhang to win the 2024 Collegiate Inventors Competition for this work.J-WAFS grant for water and food projects in IndiaJ-WAFS India Grants are intended to further the work being pursued by MIT individuals as a part of their research, innovation, entrepreneurship, coursework, or related activities. Faculty, research staff, and undergraduate and graduate students are eligible to apply. The program aims to support projects that will benefit low-income communities in India, and facilitates travel and other expenses related to directly engaging with those communities.Gokul Sampath, a PhD student in the Department of Urban Studies and Planning, and Jonathan Bessette, a PhD student in MechE, initially met through J-WAFS-sponsored conference travel, and discovered their mutual interest in the problem of arsenic in water in India. Together, they developed a cross-disciplinary proposal that received a J-WAFS India Grant. Their project is studying how women in rural India make decisions about where they fetch water for their families, and how these decisions impact exposure to groundwater contaminants like naturally-occurring arsenic. Specifically, they are developing low-cost remote sensors to better understand water-fetching practices. The grant is enabling Sampath and Bessette to equip Indian households with sensor-enabled water collection devices (“smart buckets”) that will provide them data about fetching practices in arsenic-affected villages. By demonstrating the efficacy of a sensor-based approach, the team hopes to address a major data gap in international development. “It is due to programs like the Jameel Water and Food Systems Lab that I was able to obtain the support for interdisciplinary work on connecting water security, public health, and regional planning in India,” says Sampath.J-WAFS travel grants for water conferencesIn addition to funding graduate student research, J-WAFS also provides grants for graduate students to attend water conferences worldwide. Typically, students will only receive travel funding to attend conferences where they are presenting their research. However, the J-WAFS travel grants support learning, networking, and career exploration opportunities for exceptional MIT graduate students who are interested in a career in the water sector, whether in academia, nonprofits, government, or industry.Catherine Lu ’23, MNG ’24 was awarded a 2023 Travel Grant to attend the UNC Water and Health Conference in North Carolina. The conference serves as a curated space for policymakers, practitioners, and researchers to convene and assess data, scrutinize scientific findings, and enhance new and existing strategies for expanding access to and provision of services for water, sanitation, and hygiene (WASH). Lu, who studied civil and environmental engineering, worked with Professor Dara Entekhabi on modeling and predicting droughts in Africa using satellite Soil Moisture Active Passive (SMAP) data. As she evaluated her research trajectory and career options in the water sector, Lu found the conference to be informative and enlightening. “I was able to expand my knowledge on all the sectors and issues that are related to water and the implications they have on my research topic.” Furthermore, she notes: “I was really impressed by the diverse range of people that were able to attend the conference. The global perspective offered at the conference provided a valuable context for understanding the challenges and successes of different regions around the world — from WASH education in schools in Zimbabwe and India to rural water access disparities in the United States … Being able to engage with such passionate and dedicated people has motivated me to continue progress in this sector.” Following graduation, Lu secured a position as a water resources engineer at CDM Smith, an engineering and construction firm.Daniela Morales, a master’s student in city planning in the Department of Urban Studies and Planning, was a 2024 J-WAFS Travel Grant recipient who attended World Water Week in Stockholm, Sweden. The annual global conference is organized by the Stockholm International Water Institute and convenes leading experts, decision-makers, and professionals in the water sector to actively engage in discussions and developments addressing critical water-related challenges. Morales’ research interests involve drinking water quality and access in rural and peri-urban areas affected by climate change impacts, the effects of municipal water shutoffs on marginalized communities, and the relationship between regional water management and public health outcomes. When reflecting on her experience at the conference, Morales writes: “Being part of this event has given me so much motivation to continue my professional and academic journey in water management as it relates to public health and city planning … There was so much energy that was collectively generated in the conference, and so many new ideas that I was able to process around my own career interests and my role as a future planner in water management, that the last day of the conference felt less like an ending and more of the beginning of a new chapter. I am excited to take all the information I learned to work towards my own research, and continue to build relationships with all the new contacts I made.” Morales also notes that without the support of the J-WAFS grant, “I would not have had the opportunity to make it to Stockholm and participate in such a unique week of water wisdom.”Seed grants and Solutions grantsJ-WAFS offers seed grants for early-stage research and Solutions Grants for later-stage research that is ready to move from the lab to the commercial world. Proposals for both types of grants must be submitted and led by an MIT principal investigator, but graduate students, and sometimes undergraduates, are often supported by these grants.Arjav Shah, a PhD-MBA student in MIT’s Department of Chemical Engineering and the MIT Sloan School of Management, is currently pursuing the commercialization of a water treatment technology that was first supported through a 2019 J-WAFS seed grant and then a 2022 J-WAFS Solutions Grant with Professor Patrick Doyle. The technology uses hydrogels to remove a broad range of micropollutants from water. The Solutions funding enables entrepreneurial students and postdocs to lay the groundwork to commercialize a technology by assessing use scenarios and exploring business needs with actual potential customers. “With J-WAFS’ support, we were not only able to scale up the technology, but also gain a deeper understanding of market needs and develop a strong business case,” says Shah. Shah and the Solutions team have discovered that the hydrogels could be used in several real-world contexts, ranging from large-scale industrial use to small-scale, portable, off-grid applications. “We are incredibly grateful to J-WAFS for their support, particularly in fostering industry connections and facilitating introductions to investors, potential customers, and experts,” Shah adds.Shah was also a 2023 J-WAFS Travel Grant awardee who attended Stockholm World Water Week that year. He says, “J-WAFS has played a pivotal role in both my academic journey at MIT and my entrepreneurial pursuits. J-WAFS support has helped me grow both as a scientist and an aspiring entrepreneur. The exposure and opportunities provided have allowed me to develop critical skills such as customer discovery, financial modeling, business development, fundraising, and storytelling — all essential for translating technology into real-world impact. These experiences provided invaluable insights into what it takes to bring a technology from the lab to market.”Shah is currently leading efforts to spin out a company to commercialize the hydrogel research. Since receiving J-WAFS support, the team has made major strides toward launching a startup company, including winning the Pillar VC Moonshot Prize, Cleantech Open National Grand Prize, MassCEC Catalyst Award, and participation in the NSF I-Corps National Program.J-WAFS student video competitionsJ-WAFS has hosted two video competitions: MIT Research for a Water Secure Future and MIT Research for a Food Secure Future, in honor of World Water Day and Word Food Day, respectively. In these competitions, students are tasked with creating original videos showcasing their innovative water and food research conducted at MIT. The opportunity is open to MIT students, postdocs, and recent alumni.Following a review by a distinguished panel of judges, Vishnu Jayaprakash SM ’19, PhD ’22 won first place in the 2022 J-WAFS World Food Day Student Video Competition for his video focused on eliminating pesticide pollution and waste. Jayaprakash delved into the science behind AgZen-Cloak, a new generation of agricultural sprays that prevents pesticides from bouncing off of plants and seeping into the ground, thus causing harmful runoff. The J-WAFS competition provided Jayaprakash with a platform to highlight the universal, low-cost, and environmentally sustainable benefits of AgZen-Cloak. Jayaprakash worked on similar technology as a funded student on a J-WAFS Solutions grant with Professor Kripa Varanasi. The Solutions grant, in fact, helped Jayaprakash and Varanasi to launch AgZen, a company that deploys AgZen-Cloak and other products and technologies to control the interactions of droplets and sprays with crop surfaces. AgZen is currently helping farmers sustainably tend to their agricultural plots while also protecting the environment.  In 2021, Hilary Johnson SM ’18, PhD ’22, won first place in the J-WAFS World Water Day video competition. Her video highlighted her work on a novel pump that uses adaptive hydraulics for improved pump efficiency. The pump was part of a sponsored research project with Xylem Inc., a J-WAFS Research Affiliate company, and Professor Alex Slocum of MechE. At the time, Johnson was a PhD student in Slocum’s lab. She was instrumental in the development of the pump by engineering the volute to expand and contract to meet changing system flow rates. Johnson went on to later become a 2021-22 J-WAFS Fellow, and is now a full-time mechanical engineer at the Lawrence Livermore National Laboratory.J-WAFS-supported student clubsJ-WAFS-supported student clubs provide members of the MIT student community the opportunity for networking and professional advancement through events focused on water and food systems topics.J-WAFS is a sponsor of the MIT Water Club, a student-led group that supports and promotes the engagement of the MIT community in water-sector-related activism, dissemination of information, and research innovation. The club allows students to spearhead the organization of conferences, lectures, outreach events, research showcases, and entrepreneurship competitions including the former MIT Water Innovation Prize and MIT Water Summit. J-WAFS not only sponsors the MIT Water Club financially, but offers mentorship and guidance to the leadership team.The MIT Food and Agriculture Club is also supported by J-WAFS. The club’s mission is to promote the engagement of the MIT community in food and agriculture-related topics. In doing so, the students lead initiatives to share the innovative technology and business solutions researchers are developing in food and agriculture systems. J-WAFS assists in the connection of passionate MIT students with those who are actively working in the food and agriculture industry beyond the Institute. From 2015 to 2022, J-WAFS also helped the club co-produce the Rabobank-MIT Food and Agribusiness Innovation Prize — a student business plan competition for food and agricultural startups.From 2023 onward, the MIT Water Club and the MIT Food and Ag Club have been joining forces to organize a combined prize competition: The MIT Water, Food and Agriculture (WFA) Innovation Prize. The WFA Innovation Prize is a business plan competition for student-led startups focused on any region or market. The teams present business plans involving a technology, product, service, or process that is aimed at solving a problem related to water, food, or agriculture. The competition encourages all approaches to innovation, from engineering and product design to policy and data analytics. The goal of the competition is to help emerging entrepreneurs translate research and ideas into businesses, access mentors and resources, and build networks in the water, food, and agriculture industries. J-WAFS offers financial and in-kind support, working with student leaders to plan, organize, and implement the stages of the competition through to the final pitch event. This year, J-WAFS is continuing to support the WFA team, which is led by Ali Decker, an MBA student at MIT Sloan, and Sam Jakshtis, a master’s student in MIT’s science in real estate development program. The final pitch event will take place on April 30 in the MIT Media Lab.“I’ve had the opportunity to work with Renee Robins, executive director of J-WAFS, on MIT’s Water, Food and Agriculture Innovation Prize for the past two years, and it has been both immensely valuable and a delight to have her support,” says Decker. “Renee has helped us in all areas of prize planning: brainstorming new ideas, thinking through startup finalist selection, connecting to potential sponsors and partners, and more. Above all, she supports us with passion and joy; each time we meet, I look forward to our discussion,” Decker adds.J-WAFS eventsThroughout the year, J-WAFS aims to offer events that will engage any in the MIT student community who are working in water or food systems. For example, on April 19, 2023, J-WAFS teamed up with the MIT Energy Initiative (MITEI) and the Environmental Solutions Initiative (ESI) to co-host an MIT student poster session for Earth Month. The theme of the poster session was “MIT research for a changing planet,” and it featured work from 11 MIT students with projects in water, food, energy, and the environment. The students, who represented a range of MIT departments, labs, and centers, were on hand to discuss their projects and engage with those attending the event. Attendees could vote for their favorite poster after being asked to consider which poster most clearly communicated the research problem and the potential solution. At the end of the night, votes were tallied and the winner of the “People’s Choice Award” for best poster was Elaine Liu ’24, an undergraduate in mathematics at the time of the event. Liu’s poster featured her work on managing failure cascades in systems with wind power.J-WAFS also hosts less-structured student networking events. For instance, during MIT’s Independent Activities Period (IAP) in January 2024, J-WAFS hosted an ice cream social for student networking. The informal event was an opportunity for graduate and undergraduate students from across the Institute to meet and mingle with like-minded peers working in, or interested in, water and food systems. Students were able to explain their current and future research, interests, and projects and ask questions while exchanging ideas, engaging with one another, and potentially forming collaborations, or at the very least sharing insights.Looking ahead to 10 more years of student impactOver the past decade, J-WAFS has demonstrated a strong commitment to empowering students in the water and food sectors, fostering an environment where they can confidently drive meaningful change and innovation. PhD student Jonathan Bessette sums up the J-WAFS community as a “one-of-a-kind community that enables essential research in water and food that otherwise would not be pursued. It’s this type of research that is not often the focus of major funding, yet has such a strong impact in sustainable development.”J-WAFS aims to provide students with the support and tools they need to conduct authentic and meaningful water and food-related research that will benefit communities around the world. This support, coupled with an MIT education, enables students to become leaders in sustainable water and food systems. As the second decade of J-WAFS programming begins, the J-WAFS team remains committed to fostering student collaboration across the Institute, driving innovative solutions to revitalize the world’s water and food systems while empowering the next generation of pioneers in these critical fields.  More

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    Study: Burning heavy fuel oil with scrubbers is the best available option for bulk maritime shipping

    When the International Maritime Organization enacted a mandatory cap on the sulfur content of marine fuels in 2020, with an eye toward reducing harmful environmental and health impacts, it left shipping companies with three main options.They could burn low-sulfur fossil fuels, like marine gas oil, or install cleaning systems to remove sulfur from the exhaust gas produced by burning heavy fuel oil. Biofuels with lower sulfur content offer another alternative, though their limited availability makes them a less feasible option.While installing exhaust gas cleaning systems, known as scrubbers, is the most feasible and cost-effective option, there has been a great deal of uncertainty among firms, policymakers, and scientists as to how “green” these scrubbers are.Through a novel lifecycle assessment, researchers from MIT, Georgia Tech, and elsewhere have now found that burning heavy fuel oil with scrubbers in the open ocean can match or surpass using low-sulfur fuels, when a wide variety of environmental factors is considered.The scientists combined data on the production and operation of scrubbers and fuels with emissions measurements taken onboard an oceangoing cargo ship.They found that, when the entire supply chain is considered, burning heavy fuel oil with scrubbers was the least harmful option in terms of nearly all 10 environmental impact factors they studied, such as greenhouse gas emissions, terrestrial acidification, and ozone formation.“In our collaboration with Oldendorff Carriers to broadly explore reducing the environmental impact of shipping, this study of scrubbers turned out to be an unexpectedly deep and important transitional issue,” says Neil Gershenfeld, an MIT professor, director of the Center for Bits and Atoms (CBA), and senior author of the study.“Claims about environmental hazards and policies to mitigate them should be backed by science. You need to see the data, be objective, and design studies that take into account the full picture to be able to compare different options from an apples-to-apples perspective,” adds lead author Patricia Stathatou, an assistant professor at Georgia Tech, who began this study as a postdoc in the CBA.Stathatou is joined on the paper by Michael Triantafyllou, the Henry L. and Grace Doherty and others at the National Technical University of Athens in Greece and the maritime shipping firm Oldendorff Carriers. The research appears today in Environmental Science and Technology.Slashing sulfur emissionsHeavy fuel oil, traditionally burned by bulk carriers that make up about 30 percent of the global maritime fleet, usually has a sulfur content around 2 to 3 percent. This is far higher than the International Maritime Organization’s 2020 cap of 0.5 percent in most areas of the ocean and 0.1 percent in areas near population centers or environmentally sensitive regions.Sulfur oxide emissions contribute to air pollution and acid rain, and can damage the human respiratory system.In 2018, fewer than 1,000 vessels employed scrubbers. After the cap went into place, higher prices of low-sulfur fossil fuels and limited availability of alternative fuels led many firms to install scrubbers so they could keep burning heavy fuel oil.Today, more than 5,800 vessels utilize scrubbers, the majority of which are wet, open-loop scrubbers.“Scrubbers are a very mature technology. They have traditionally been used for decades in land-based applications like power plants to remove pollutants,” Stathatou says.A wet, open-loop marine scrubber is a huge, metal, vertical tank installed in a ship’s exhaust stack, above the engines. Inside, seawater drawn from the ocean is sprayed through a series of nozzles downward to wash the hot exhaust gases as they exit the engines.The seawater interacts with sulfur dioxide in the exhaust, converting it to sulfates — water-soluble, environmentally benign compounds that naturally occur in seawater. The washwater is released back into the ocean, while the cleaned exhaust escapes to the atmosphere with little to no sulfur dioxide emissions.But the acidic washwater can contain other combustion byproducts like heavy metals, so scientists wondered if scrubbers were comparable, from a holistic environmental point of view, to burning low-sulfur fuels.Several studies explored toxicity of washwater and fuel system pollution, but none painted a full picture.The researchers set out to fill that scientific gap.A “well-to-wake” analysisThe team conducted a lifecycle assessment using a global environmental database on production and transport of fossil fuels, such as heavy fuel oil, marine gas oil, and very-low sulfur fuel oil. Considering the entire lifecycle of each fuel is key, since producing low-sulfur fuel requires extra processing steps in the refinery, causing additional emissions of greenhouse gases and particulate matter.“If we just look at everything that happens before the fuel is bunkered onboard the vessel, heavy fuel oil is significantly more low-impact, environmentally, than low-sulfur fuels,” she says.The researchers also collaborated with a scrubber manufacturer to obtain detailed information on all materials, production processes, and transportation steps involved in marine scrubber fabrication and installation.“If you consider that the scrubber has a lifetime of about 20 years, the environmental impacts of producing the scrubber over its lifetime are negligible compared to producing heavy fuel oil,” she adds.For the final piece, Stathatou spent a week onboard a bulk carrier vessel in China to measure emissions and gather seawater and washwater samples. The ship burned heavy fuel oil with a scrubber and low-sulfur fuels under similar ocean conditions and engine settings.Collecting these onboard data was the most challenging part of the study.“All the safety gear, combined with the heat and the noise from the engines on a moving ship, was very overwhelming,” she says.Their results showed that scrubbers reduce sulfur dioxide emissions by 97 percent, putting heavy fuel oil on par with low-sulfur fuels according to that measure. The researchers saw similar trends for emissions of other pollutants like carbon monoxide and nitrous oxide.In addition, they tested washwater samples for more than 60 chemical parameters, including nitrogen, phosphorus, polycyclic aromatic hydrocarbons, and 23 metals.The concentrations of chemicals regulated by the IMO were far below the organization’s requirements. For unregulated chemicals, the researchers compared the concentrations to the strictest limits for industrial effluents from the U.S. Environmental Protection Agency and European Union.Most chemical concentrations were at least an order of magnitude below these requirements.In addition, since washwater is diluted thousands of times as it is dispersed by a moving vessel, the concentrations of such chemicals would be even lower in the open ocean.These findings suggest that the use of scrubbers with heavy fuel oil can be considered as equal to or more environmentally friendly than low-sulfur fuels across many of the impact categories the researchers studied.“This study demonstrates the scientific complexity of the waste stream of scrubbers. Having finally conducted a multiyear, comprehensive, and peer-reviewed study, commonly held fears and assumptions are now put to rest,” says Scott Bergeron, managing director at Oldendorff Carriers and co-author of the study.“This first-of-its-kind study on a well-to-wake basis provides very valuable input to ongoing discussion at the IMO,” adds Thomas Klenum, executive vice president of innovation and regulatory affairs at the Liberian Registry, emphasizing the need “for regulatory decisions to be made based on scientific studies providing factual data and conclusions.”Ultimately, this study shows the importance of incorporating lifecycle assessments into future environmental impact reduction policies, Stathatou says.“There is all this discussion about switching to alternative fuels in the future, but how green are these fuels? We must do our due diligence to compare them equally with existing solutions to see the costs and benefits,” she adds.This study was supported, in part, by Oldendorff Carriers. More