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Years after massive sewage spill, El Segundo still stinks. Why can't L.A. fix the problem?

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Monday, December 16, 2024

On the worst days, Tamara Kcehowski said, she has thrown up when the stench from Los Angeles’ nearby sewage plant overwhelms her El Segundo apartment. She said her dog, Maggie, has even retched alongside her. On the not-so-bad days, she says she often deals with a dull headache or burning eyes. Some mornings, she wakes up gagging or coughing. None of this was part of Kcehowski’s life before July 2021, when major failures at the nearby Hyperion Water Reclamation Plant dumped millions of gallons of untreated sewage into Santa Monica Bay and released high levels of hydrogen sulfide, a gas that smells like rotten eggs and can cause health issues.At the time, Kcehowski was hopeful the facility’s response would be swift and that her community would suffer the stinky mess for only a few days — or at worst a few weeks. But now, more than three years later, the noxious odors and elevated hydrogen sulfide emissions persist, despite repeated complaints and appeals to the city of Los Angeles, air quality regulators and local officials. Although she’s lived in El Segundo with her daughter since the early 2000s, she now wonders if her only recourse is to move.“You’ve had three years to take care of this issue, and you still haven’t,” said Kcehowski, 58. “We’re still suffering, why?” Tamara Kcehowski is frustrated by smells emanating from the Hyperion Water Reclamation Plant. She said the smells have been sickening and continue now more than three years later. (Genaro Molina/Los Angeles Times) Hyperion — the largest wastewater treatment facility west of the Rockies — sprawls across 200 acres of oceanfront Los Angeles and sits just outside the city limits of El Segundo. Every day, 4 million inhabitants of L.A. and 29 other cities — including El Segundo — flush a quarter-billion gallons of wastewater into Hyperion’s treatment tanks. While most people are blissfully ignorant of their wastewater’s journey after showering or using the toilet, it’s become an unpleasant fact of life for many El Segundo residents. Many complain the city of Los Angeles has ignored their plight and has failed to make needed changes to limit, and track, odors. They worry their concerns will always be outweighed by the sanitation needs of millions.“There’s no question it’s worse than it ever has been, at least going back to the early ’90s when it was really bad,” said El Segundo Mayor Drew Boyles. “It’s incredibly frustrating. ... It doesn’t feel like the city of L.A. is taking this matter as seriously as they should.”For its part, the facility has slowly addressed a laundry list of needed improvements in the aftermath of the July 2021 spill, some of which have dramatically improved odors. “It’s services cannot be stopped, diverted or stored,” said Tonya Shelton, a spokesperson for L.A. Sanitation and Environment, the city department that manages the sewage plant. “Hyperion will nonetheless continue to work closely with both the [South Coast Air Quality Management District] and the City of El Segundo to ensure that operations are not only compliant, but reflect a spirit of partnership for the surrounding community.”Odor complaints still upIn the three years before the July 2021 spill, residents complained fewer than 150 times about odors around Hyperion.But in the three months after the spill — which officials found was likely caused by equipment failures, operational missteps and staffing issues — more than 2,500 odor complaints flooded regulators, according to South Coast AQMD data. Although community concern peaked in those initial months, Hyperion continues to be barraged by odor complaints, which routinely reach into the hundreds each month.The alarming uptick in complaints led to increased oversight by the local air district beginning in 2022, when regulators determined L.A. Sanitation was “unable to contain the sewage odors at Hyperion and cannot conduct operations at the wastewater treatment plant without being in violation” of district rules and regulations.An abatement order required the plant to improve infrastructure, operations and monitoring. It was aimed at minimizing smells primarily from hydrogen sulfide, a known byproduct of wastewater treatment facilities released during the breakdown of organic matter. It can be deadly at high levels, according to the Environmental Protection Agency, but both lower and longer-term exposure can also cause health symptoms, particularly for the respiratory and nervous systems. After more than two years under the order, L.A. Sanitation and AQMD officials reported last month that Hyperion had successfully met all the mandated conditions — but members of the air quality hearing board were not convinced the problem had been resolved. “Everything that is being done is not getting rid of the odors,” Cynthia Verdugo-Peralta, a board member, said at the late November hearing. “The problem still remains — the odors are still affecting the public in such a negative way. ... The city of El Segundo, especially, is still suffering.”At that hearing, a South Coast AQMD air quality inspector testified that there were no remaining shortcomings related to the abatement order. However, he said that during his recent visits to El Segundo there “are pockets that I can consistently detect odors in the community.”The board members voted unanimously to extend oversight of Hyperion through at least next August, instead of terminating the abatement order in January. Boyles said he was in “disbelief” that the board even considered lifting the abatement order, but was glad it stood by his city’s concerns.Still, he and the El Segundo City Council are considering filing a lawsuit against the city of L.A. It’s something Boyles considers a last resort, but the city has taken that route in the past when conditions around the sewage plant have deteriorated. El Segundo Mayor Drew Boyles and City Manager Darrell George, from left, are photographed near the Hyperion Water Reclamation Plant. (Christina House/Los Angeles Times) Two groups of residents have already filed suit against L.A.’s sanitation department over air quality issues immediately after the spill, one specifically alleging the city’s failure to monitor noxious gases. Those cases remain in litigation.After the spill, Hyperion officials admitted that there were several shortcomings and repairs were needed. L.A. has since spent an estimated $114 million on improvements, including placing new covers on a tank that AQMD officials found to be a principal source of odors, Shelton said. The plant has also enhanced employee training, implemented an air monitoring system along its perimeter, increased neighborhood checks for odors and, most recently, hired environmental nonprofit Heal the Bay to improve community relations.An external review of the plant after the spill called for 33 immediate fixes, of which about 85% have been completed, the city has reported. But Shelton emphasized that an odor-free plant handling millions of gallons of sewage a day is not realistic. “Despite the completion of these projects, and though Hyperion continues to put concentrated effort into minimizing odors, odors are a part of work at any wastewater treatment plant, and the presence of odors does not always mean there is a problem to remedy or changes to implement,” Shelton said in a statement. “Hyperion continues to work with the community on this issue.”Air quality compliance issuesFor decades, a single air quality violation in a year was rare for Hyperion. But since the 2021 sewage spill, Hyperion has seen a surge in compliance issues. In just the last six months, the South Coast AQMD has issued the facility eight such nuisance violations, which indicate a discharge of air contaminants causing odors traced back to Hyperion, according to recent inspector testimony. Officials have also issued some violations tied to hydrogen sulfide emissions. While Hyperion historically tested for the colorless toxic gas in certain scenarios, it was only in May 2022 — after months of complaints and violations — that Hyperion began consistently monitoring for hydrogen sulfide along its eastern border with El Segundo neighborhoods.Since then, there have been several occasions when levels of the compound have spiked above 30 parts per billion on average for an hour — California’s standard for acute risk from hydrogen sulfide. Such high levels were recorded three times in 2022, four times in 2023 and once in February of this year, Shelton said. In one instance from June 2023, hydrogen sulfide reached a one-hour average of 64 ppb — more than double California’s standard — when Hyperion operators had turned off pollution control devices, or scrubbers, for maintenance. Shelton noted that during several of the other spikes, there were issues at the plant or heightened winds that likely influenced the hydrogen sulfide measurements, but some were unexplained. However, Shelton noted that “Hyperion is consistently well below” the 30 ppb level.In recent months, the monitors have regularly recorded the gas at much lower levels, around 1 to 3 ppb, though spikes have occurred. The state of California considers a long-term average of 7 ppb, across several months, to be dangerous. Officials have found that people can detect hydrogen sulfide at levels from 0.05 ppb to 30 ppb, though it’s not exactly clear the levels at which symptoms occur, and this likely varies by person. Research on the effects of chronic or low-level exposure remains limited. The Los Angeles County Public Health Department in 2022 reported that “odors alone from hydrogen sulfide cause well-documented physiological responses, including nausea, vomiting, headache, dizziness and other symptoms.” Some studies have also found that experiences with odor can alter sensitivities, as well as increase stress. For those residents who say they smell the gas regularly, chronic exposure is a worry. “I’m concerned with a 1 [ppb] every single day for 365 days a year,” Kcehowski said. “What is this doing for us for this length of time?” Tamara Kcehowski walks through her El Segundo neighborhood, which has been dealing with foul odors from the nearby Hyperion Water Reclamation Plant. (Genaro Molina/Los Angeles Times) Funding an unglamorous jobHyperion has been in operation since 1925, and underwent its last major upgrade in the 1990s. Since that time, it has been instrumental in transforming Los Angeles County beaches from a potential health hazard to a worldwide tourist destination. But even with such an important — albeit unglamorous — role in keeping Santa Monica Bay clean for humans and sealife, accessing the necessary funds for Hyperion’s upkeep has been a challenge, said Elsa Devienne, author of the book “Sand Rush,” which chronicles the history of L.A.’s coast.“Nobody wants to think about sewage, nobody wants to spend a cent on it,” Devienne said. “So investment in those things only happened when things get really, really bad.”Many times, state or federal oversight — often in the form of lawsuits — has been the only surefire way to enact necessary change at the plant, Devienne said. That history again played out this year. A settlement with the U.S. Environmental Protection Agency required L.A. to invest $20 million into improvements at the plant. But notably, that deal focused only on water quality issues — not emissions or air quality.There is, however, some funding on the horizon: for the first time in years, the Los Angeles City Council approved a sewer fee rate hike, which is expected to generate nearly $115 million in additional funds for L.A. Sanitation in its first fiscal year. By 2028, the increases are expected to more than double a typical single-family home’s bimonthly sewer fee, from $72.27 to $155.55, estimates show.“The project lists are long, but they have been working really hard lifting up the odor control projects, to support the city [of El Segundo] to be better neighbors,” said Meredith McCarthy, senior director of community outreach for Heal the Bay. The last few months of improvements have addressed the most urgent issues and what McCarthy called low-hanging fruit, but she said the facility’s maintenance backlog remains “pretty spectacular” and continued investment is needed, especially if Hyperion is going to play its important role in the city’s aggressive shift to recycled water over the next decade. ‘No change, wasted effort’While McCarthy is hopeful the plant is now on the right path, she knows it doesn’t change the last few years of suffering felt by many El Segundo residents.Although overall complaints have decreased, Boyles insists that its not because foul odors are no longer an issue. “Our residents are so fatigued by this matter,” Boyles said. “People are getting worn down. ... We cannot give up on them.”Chuck Espinoza, who lives not far from the plant, is among those who have given up. He was submitting odor complaints most days of the month soon after the spill, when he and his family for the first time started suffering from headaches and burning eyes. But the multi-step complaint process eventually felt like a pointless time-suck.“No change, wasted effort and it’s all for nothing,” Espinoza, 51, said. “Giving up for me has been the best thing for my sanity.”Before the spill, he estimated that his neighborhood smelled funky once a week. But after July 2021 it’s been at least three to four times a week, he said, and he described the recent odors as more chemical.“I don’t think we even know what we’re being exposed to,” Espinoza said. He said he worries about long-term effects, including for his children, but he said he feels “completely powerless to even address what those are.”But for some residents, Hyperion hasn’t changed much about life in the industry-surrounded city. Chuck Nicolai, who lives only a few houses from Espinoza, said he and his wife haven’t noticed any dramatic changes or issues since the spill. When he bought his house in the mid-1980s, Nicolai remembers a horrible smell from the plant. But since it modernized in the 1990s, he said he can’t complain.He considers it a part of life in El Segundo, similar to dealing with fumes from the nearby Chevron plant or the constant noise from the airport. “It’s SoCal coastal, the best climate in the world,” Nicolai, 79, said. “You live here, you get used to the jets and Hyperion.”

Three years after a raw sewage spill, residents living near L.A.'s Hyperion wastewater plant say they are still dealing with foul odors and health issues.

On the worst days, Tamara Kcehowski said, she has thrown up when the stench from Los Angeles’ nearby sewage plant overwhelms her El Segundo apartment. She said her dog, Maggie, has even retched alongside her.

On the not-so-bad days, she says she often deals with a dull headache or burning eyes. Some mornings, she wakes up gagging or coughing.

None of this was part of Kcehowski’s life before July 2021, when major failures at the nearby Hyperion Water Reclamation Plant dumped millions of gallons of untreated sewage into Santa Monica Bay and released high levels of hydrogen sulfide, a gas that smells like rotten eggs and can cause health issues.

At the time, Kcehowski was hopeful the facility’s response would be swift and that her community would suffer the stinky mess for only a few days — or at worst a few weeks.

But now, more than three years later, the noxious odors and elevated hydrogen sulfide emissions persist, despite repeated complaints and appeals to the city of Los Angeles, air quality regulators and local officials. Although she’s lived in El Segundo with her daughter since the early 2000s, she now wonders if her only recourse is to move.

“You’ve had three years to take care of this issue, and you still haven’t,” said Kcehowski, 58. “We’re still suffering, why?”

A woman stands in a fenced area with high tension wires in the background.

Tamara Kcehowski is frustrated by smells emanating from the Hyperion Water Reclamation Plant. She said the smells have been sickening and continue now more than three years later.

(Genaro Molina/Los Angeles Times)

Hyperion — the largest wastewater treatment facility west of the Rockies — sprawls across 200 acres of oceanfront Los Angeles and sits just outside the city limits of El Segundo. Every day, 4 million inhabitants of L.A. and 29 other cities — including El Segundo — flush a quarter-billion gallons of wastewater into Hyperion’s treatment tanks.

While most people are blissfully ignorant of their wastewater’s journey after showering or using the toilet, it’s become an unpleasant fact of life for many El Segundo residents. Many complain the city of Los Angeles has ignored their plight and has failed to make needed changes to limit, and track, odors. They worry their concerns will always be outweighed by the sanitation needs of millions.

“There’s no question it’s worse than it ever has been, at least going back to the early ’90s when it was really bad,” said El Segundo Mayor Drew Boyles. “It’s incredibly frustrating. ... It doesn’t feel like the city of L.A. is taking this matter as seriously as they should.”

For its part, the facility has slowly addressed a laundry list of needed improvements in the aftermath of the July 2021 spill, some of which have dramatically improved odors.

“It’s services cannot be stopped, diverted or stored,” said Tonya Shelton, a spokesperson for L.A. Sanitation and Environment, the city department that manages the sewage plant. “Hyperion will nonetheless continue to work closely with both the [South Coast Air Quality Management District] and the City of El Segundo to ensure that operations are not only compliant, but reflect a spirit of partnership for the surrounding community.”

Odor complaints still up

In the three years before the July 2021 spill, residents complained fewer than 150 times about odors around Hyperion.

But in the three months after the spill — which officials found was likely caused by equipment failures, operational missteps and staffing issues — more than 2,500 odor complaints flooded regulators, according to South Coast AQMD data. Although community concern peaked in those initial months, Hyperion continues to be barraged by odor complaints, which routinely reach into the hundreds each month.

The alarming uptick in complaints led to increased oversight by the local air district beginning in 2022, when regulators determined L.A. Sanitation was “unable to contain the sewage odors at Hyperion and cannot conduct operations at the wastewater treatment plant without being in violation” of district rules and regulations.

An abatement order required the plant to improve infrastructure, operations and monitoring. It was aimed at minimizing smells primarily from hydrogen sulfide, a known byproduct of wastewater treatment facilities released during the breakdown of organic matter. It can be deadly at high levels, according to the Environmental Protection Agency, but both lower and longer-term exposure can also cause health symptoms, particularly for the respiratory and nervous systems.

After more than two years under the order, L.A. Sanitation and AQMD officials reported last month that Hyperion had successfully met all the mandated conditions — but members of the air quality hearing board were not convinced the problem had been resolved.

“Everything that is being done is not getting rid of the odors,” Cynthia Verdugo-Peralta, a board member, said at the late November hearing. “The problem still remains — the odors are still affecting the public in such a negative way. ... The city of El Segundo, especially, is still suffering.”

At that hearing, a South Coast AQMD air quality inspector testified that there were no remaining shortcomings related to the abatement order. However, he said that during his recent visits to El Segundo there “are pockets that I can consistently detect odors in the community.”

The board members voted unanimously to extend oversight of Hyperion through at least next August, instead of terminating the abatement order in January.

Boyles said he was in “disbelief” that the board even considered lifting the abatement order, but was glad it stood by his city’s concerns.

Still, he and the El Segundo City Council are considering filing a lawsuit against the city of L.A. It’s something Boyles considers a last resort, but the city has taken that route in the past when conditions around the sewage plant have deteriorated.

El Segundo Mayor Drew Boyles and City Manager Darrell George stand in front of the Hyperion Water Reclamation Plant.

El Segundo Mayor Drew Boyles and City Manager Darrell George, from left, are photographed near the Hyperion Water Reclamation Plant.

(Christina House/Los Angeles Times)

Two groups of residents have already filed suit against L.A.’s sanitation department over air quality issues immediately after the spill, one specifically alleging the city’s failure to monitor noxious gases. Those cases remain in litigation.

After the spill, Hyperion officials admitted that there were several shortcomings and repairs were needed. L.A. has since spent an estimated $114 million on improvements, including placing new covers on a tank that AQMD officials found to be a principal source of odors, Shelton said. The plant has also enhanced employee training, implemented an air monitoring system along its perimeter, increased neighborhood checks for odors and, most recently, hired environmental nonprofit Heal the Bay to improve community relations.

An external review of the plant after the spill called for 33 immediate fixes, of which about 85% have been completed, the city has reported.

But Shelton emphasized that an odor-free plant handling millions of gallons of sewage a day is not realistic.

“Despite the completion of these projects, and though Hyperion continues to put concentrated effort into minimizing odors, odors are a part of work at any wastewater treatment plant, and the presence of odors does not always mean there is a problem to remedy or changes to implement,” Shelton said in a statement. “Hyperion continues to work with the community on this issue.”

Air quality compliance issues

For decades, a single air quality violation in a year was rare for Hyperion. But since the 2021 sewage spill, Hyperion has seen a surge in compliance issues. In just the last six months, the South Coast AQMD has issued the facility eight such nuisance violations, which indicate a discharge of air contaminants causing odors traced back to Hyperion, according to recent inspector testimony.

Officials have also issued some violations tied to hydrogen sulfide emissions.

While Hyperion historically tested for the colorless toxic gas in certain scenarios, it was only in May 2022 — after months of complaints and violations — that Hyperion began consistently monitoring for hydrogen sulfide along its eastern border with El Segundo neighborhoods.

Since then, there have been several occasions when levels of the compound have spiked above 30 parts per billion on average for an hour — California’s standard for acute risk from hydrogen sulfide. Such high levels were recorded three times in 2022, four times in 2023 and once in February of this year, Shelton said.

In one instance from June 2023, hydrogen sulfide reached a one-hour average of 64 ppb — more than double California’s standard — when Hyperion operators had turned off pollution control devices, or scrubbers, for maintenance. Shelton noted that during several of the other spikes, there were issues at the plant or heightened winds that likely influenced the hydrogen sulfide measurements, but some were unexplained. However, Shelton noted that “Hyperion is consistently well below” the 30 ppb level.

In recent months, the monitors have regularly recorded the gas at much lower levels, around 1 to 3 ppb, though spikes have occurred. The state of California considers a long-term average of 7 ppb, across several months, to be dangerous.

Officials have found that people can detect hydrogen sulfide at levels from 0.05 ppb to 30 ppb, though it’s not exactly clear the levels at which symptoms occur, and this likely varies by person. Research on the effects of chronic or low-level exposure remains limited.

The Los Angeles County Public Health Department in 2022 reported that “odors alone from hydrogen sulfide cause well-documented physiological responses, including nausea, vomiting, headache, dizziness and other symptoms.” Some studies have also found that experiences with odor can alter sensitivities, as well as increase stress.

For those residents who say they smell the gas regularly, chronic exposure is a worry.

“I’m concerned with a 1 [ppb] every single day for 365 days a year,” Kcehowski said. “What is this doing for us for this length of time?”

El Segundo resident Tamara Kcehowski walks through her neighborhood.

Tamara Kcehowski walks through her El Segundo neighborhood, which has been dealing with foul odors from the nearby Hyperion Water Reclamation Plant.

(Genaro Molina/Los Angeles Times)

Funding an unglamorous job

Hyperion has been in operation since 1925, and underwent its last major upgrade in the 1990s. Since that time, it has been instrumental in transforming Los Angeles County beaches from a potential health hazard to a worldwide tourist destination.

But even with such an important — albeit unglamorous — role in keeping Santa Monica Bay clean for humans and sealife, accessing the necessary funds for Hyperion’s upkeep has been a challenge, said Elsa Devienne, author of the book “Sand Rush,” which chronicles the history of L.A.’s coast.

“Nobody wants to think about sewage, nobody wants to spend a cent on it,” Devienne said. “So investment in those things only happened when things get really, really bad.”

Many times, state or federal oversight — often in the form of lawsuits — has been the only surefire way to enact necessary change at the plant, Devienne said.

That history again played out this year. A settlement with the U.S. Environmental Protection Agency required L.A. to invest $20 million into improvements at the plant. But notably, that deal focused only on water quality issues — not emissions or air quality.

There is, however, some funding on the horizon: for the first time in years, the Los Angeles City Council approved a sewer fee rate hike, which is expected to generate nearly $115 million in additional funds for L.A. Sanitation in its first fiscal year. By 2028, the increases are expected to more than double a typical single-family home’s bimonthly sewer fee, from $72.27 to $155.55, estimates show.

“The project lists are long, but they have been working really hard lifting up the odor control projects, to support the city [of El Segundo] to be better neighbors,” said Meredith McCarthy, senior director of community outreach for Heal the Bay.

The last few months of improvements have addressed the most urgent issues and what McCarthy called low-hanging fruit, but she said the facility’s maintenance backlog remains “pretty spectacular” and continued investment is needed, especially if Hyperion is going to play its important role in the city’s aggressive shift to recycled water over the next decade.

‘No change, wasted effort’

While McCarthy is hopeful the plant is now on the right path, she knows it doesn’t change the last few years of suffering felt by many El Segundo residents.

Although overall complaints have decreased, Boyles insists that its not because foul odors are no longer an issue.

“Our residents are so fatigued by this matter,” Boyles said. “People are getting worn down. ... We cannot give up on them.”

Chuck Espinoza, who lives not far from the plant, is among those who have given up. He was submitting odor complaints most days of the month soon after the spill, when he and his family for the first time started suffering from headaches and burning eyes. But the multi-step complaint process eventually felt like a pointless time-suck.

“No change, wasted effort and it’s all for nothing,” Espinoza, 51, said. “Giving up for me has been the best thing for my sanity.”

Before the spill, he estimated that his neighborhood smelled funky once a week. But after July 2021 it’s been at least three to four times a week, he said, and he described the recent odors as more chemical.

“I don’t think we even know what we’re being exposed to,” Espinoza said. He said he worries about long-term effects, including for his children, but he said he feels “completely powerless to even address what those are.”

But for some residents, Hyperion hasn’t changed much about life in the industry-surrounded city.

Chuck Nicolai, who lives only a few houses from Espinoza, said he and his wife haven’t noticed any dramatic changes or issues since the spill. When he bought his house in the mid-1980s, Nicolai remembers a horrible smell from the plant. But since it modernized in the 1990s, he said he can’t complain.

He considers it a part of life in El Segundo, similar to dealing with fumes from the nearby Chevron plant or the constant noise from the airport.

“It’s SoCal coastal, the best climate in the world,” Nicolai, 79, said. “You live here, you get used to the jets and Hyperion.”

Read the full story here.
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New method improves the reliability of statistical estimations

The technique can help scientists in economics, public health, and other fields understand whether to trust the results of their experiments.

Let’s say an environmental scientist is studying whether exposure to air pollution is associated with lower birth weights in a particular county.They might train a machine-learning model to estimate the magnitude of this association, since machine-learning methods are especially good at learning complex relationships.Standard machine-learning methods excel at making predictions and sometimes provide uncertainties, like confidence intervals, for these predictions. However, they generally don’t provide estimates or confidence intervals when determining whether two variables are related. Other methods have been developed specifically to address this association problem and provide confidence intervals. But, in spatial settings, MIT researchers found these confidence intervals can be completely off the mark.When variables like air pollution levels or precipitation change across different locations, common methods for generating confidence intervals may claim a high level of confidence when, in fact, the estimation completely failed to capture the actual value. These faulty confidence intervals can mislead the user into trusting a model that failed.After identifying this shortfall, the researchers developed a new method designed to generate valid confidence intervals for problems involving data that vary across space. In simulations and experiments with real data, their method was the only technique that consistently generated accurate confidence intervals.This work could help researchers in fields like environmental science, economics, and epidemiology better understand when to trust the results of certain experiments.“There are so many problems where people are interested in understanding phenomena over space, like weather or forest management. We’ve shown that, for this broad class of problems, there are more appropriate methods that can get us better performance, a better understanding of what is going on, and results that are more trustworthy,” says Tamara Broderick, an associate professor in MIT’s Department of Electrical Engineering and Computer Science (EECS), a member of the Laboratory for Information and Decision Systems (LIDS) and the Institute for Data, Systems, and Society, an affiliate of the Computer Science and Artificial Intelligence Laboratory (CSAIL), and senior author of this study.Broderick is joined on the paper by co-lead authors David R. Burt, a postdoc, and Renato Berlinghieri, an EECS graduate student; and Stephen Bates an assistant professor in EECS and member of LIDS. The research was recently presented at the Conference on Neural Information Processing Systems.Invalid assumptionsSpatial association involves studying how a variable and a certain outcome are related over a geographic area. For instance, one might want to study how tree cover in the United States relates to elevation.To solve this type of problem, a scientist could gather observational data from many locations and use it to estimate the association at a different location where they do not have data.The MIT researchers realized that, in this case, existing methods often generate confidence intervals that are completely wrong. A model might say it is 95 percent confident its estimation captures the true relationship between tree cover and elevation, when it didn’t capture that relationship at all.After exploring this problem, the researchers determined that the assumptions these confidence interval methods rely on don’t hold up when data vary spatially.Assumptions are like rules that must be followed to ensure results of a statistical analysis are valid. Common methods for generating confidence intervals operate under various assumptions.First, they assume that the source data, which is the observational data one gathered to train the model, is independent and identically distributed. This assumption implies that the chance of including one location in the data has no bearing on whether another is included. But, for example, U.S. Environmental Protection Agency (EPA) air sensors are placed with other air sensor locations in mind.Second, existing methods often assume that the model is perfectly correct, but this assumption is never true in practice. Finally, they assume the source data are similar to the target data where one wants to estimate.But in spatial settings, the source data can be fundamentally different from the target data because the target data are in a different location than where the source data were gathered.For instance, a scientist might use data from EPA pollution monitors to train a machine-learning model that can predict health outcomes in a rural area where there are no monitors. But the EPA pollution monitors are likely placed in urban areas, where there is more traffic and heavy industry, so the air quality data will be much different than the air quality data in the rural area.In this case, estimates of association using the urban data suffer from bias because the target data are systematically different from the source data.A smooth solutionThe new method for generating confidence intervals explicitly accounts for this potential bias.Instead of assuming the source and target data are similar, the researchers assume the data vary smoothly over space.For instance, with fine particulate air pollution, one wouldn’t expect the pollution level on one city block to be starkly different than the pollution level on the next city block. Instead, pollution levels would smoothly taper off as one moves away from a pollution source.“For these types of problems, this spatial smoothness assumption is more appropriate. It is a better match for what is actually going on in the data,” Broderick says.When they compared their method to other common techniques, they found it was the only one that could consistently produce reliable confidence intervals for spatial analyses. In addition, their method remains reliable even when the observational data are distorted by random errors.In the future, the researchers want to apply this analysis to different types of variables and explore other applications where it could provide more reliable results.This research was funded, in part, by an MIT Social and Ethical Responsibilities of Computing (SERC) seed grant, the Office of Naval Research, Generali, Microsoft, and the National Science Foundation (NSF).

Gas Stoves Are Poisoning Americans by Releasing Toxic Fumes Associated With Asthma and Lung Cancer

In the United States, gas stoves are the main source of indoor nitrogen dioxide—a toxic gas tied to many health problems—according to a new study

Gas Stoves Are Poisoning Americans by Releasing Toxic Fumes Associated With Asthma and Lung Cancer In the United States, gas stoves are the main source of indoor nitrogen dioxide—a toxic gas tied to many health problems—according to a new study Sarah Kuta - Daily Correspondent December 11, 2025 9:13 a.m. Gas stoves are responsible for more than half of some Americans’ total exposure to toxic nitrogen dioxide, a new study suggests. Pexels A hidden danger may be lurking in your kitchen. Many Americans are breathing in nitrogen dioxide—a harmful pollutant that’s been linked with asthma and lung cancer—from fumes emitted by their gas stoves. A new study, published this month in the journal PNAS Nexus, suggests that gas stoves are the main source of indoor nitrogen dioxide pollution in the United States, responsible for more than half of some Americans’ total exposure to the gas. “We’ve spent billions of dollars cleaning up our air outdoors and nothing to clean up our air indoors,” study co-author Robert Jackson, an environmental scientist at Stanford University, tells SFGATE’s Anna FitzGerald Guth. “As our air outdoors gets cleaner and cleaner, a higher proportion of the pollution we breathe comes from indoor sources.” Scientists and public health experts have long known that nitrogen dioxide is bad for human health. The reddish-brown gas can irritate airways and worsen or even contribute to the development of respiratory diseases like asthma. Children and older individuals are particularly susceptible to its effects. Nitrogen dioxide is a byproduct of burning fuel, so most emissions come from vehicles, power plants and off-road equipment. However, indoors, the primary culprit is the gas stove, the household appliance that burns natural gas or propane to produce controlled flames under individual burners. It’s relatively easy to keep tabs on outdoor nitrogen dioxide concentrations and estimate their corresponding exposure risks, thanks to satellites and ground-level stations located across the country. By contrast, however, indoor sources are “neither systematically monitored nor estimated,” the researchers write in the paper. Did you know? Bans on gas Berkeley, California, became the first city to prohibit gas hookups in most new buildings in 2019, although the ordinance was halted in 2024 after the California Restaurant Association sued. Still, 130 local governments have now implemented zero-emission building ordinances, according to the Building Decarbonization Coalition. For the study, Jackson and his colleagues performed a ZIP-code-level estimate of how much total nitrogen dioxide communities are exposed to. Information came from two databases tracking outdoor nitrogen dioxide concentrations and a building energy use database, which helped the team construct characteristics of 133 million residential dwellings across the country, along with their home appliances. Among individuals who use gas stoves, the appliances are responsible for roughly a quarter of their overall nitrogen dioxide exposure on average, the team found. For those who cook more frequently or for longer durations, gas stoves can be responsible for as much as 57 percent of their total exposure. “Our research shows that if you use a gas stove, you’re often breathing as much nitrogen dioxide pollution indoors from your stove as you are from all outdoor sources combined,” says Jackson in a Stanford statement. Individuals who use gas stoves are exposed to roughly 25 percent more total residential nitrogen dioxide over the long term than those who use electric stoves, which do not emit the gas. Total exposure tends to be highest in big cities, where people often have small living spaces and outdoor levels are also high. Switching from a gas to an electric stove would help roughly 22 million Americans dip below the maximum nitrogen dioxide exposure levels recommended by the World Health Organization, the analyses suggest. The authors recommend replacing gas stoves with electric models whenever possible. “You would never willingly stand over the tailpipe of your car, breathing in pollution,” Jackson tells Women’s Health’s Korin Miller. “Why breathe the same toxins every day in your kitchen?” Dylan Plummer, acting deputy director for building electrification for the Sierra Club, a nonprofit environmental organization, agrees. Plummer, who was not involved with the research, tells Inside Climate News’ Phil McKenna that “years from now, we will look back at the common practice of burning fossil fuels in our homes with horror.” If swapping stoves is not possible, experts have some other tips for reducing nitrogen dioxide exposure. “One thing people could do is to minimize the time the stoves are on,” Jamie Alan, a toxicologist at Michigan State University who was not involved with the research, tells Women’s Health. “Another suggestion would be to increase ventilation,” such as by turning on the range hood and opening a window. Other suggestions by the New York Times’ Rachel Wharton include using a portable induction countertop unit or electric kitchen gadgets like tea kettles, toaster ovens and slow cookers. Get the latest stories in your inbox every weekday.

Parents Might Pass Depression Down To Kids Through One Specific Symptom, Experts Say

By Dennis Thompson HealthDay ReporterTHURSDAY, Dec. 11, 2025 (HealthDay News) — Children of depressed parents are more likely to develop depression...

By Dennis Thompson HealthDay ReporterTHURSDAY, Dec. 11, 2025 (HealthDay News) — Children of depressed parents are more likely to develop depression themselves, and a new study suggests this risk might be tied to one specific symptom of depression.It’s already known that depression in parents can affect how children’s brains respond to positive and negative feedback, researchers said.“If parents are experiencing forms of depression where they’re not enjoying things and aren’t interested in things, that seems to be impacting how their kids are responding to what’s going on around them,” senior researcher Brandon Gibb, director of the Mood Disorders Institute at Binghamton University, said in a news release.“They’re less reactive to positive things and negative things,” he continued. “It seems that parents’ experiences of anhedonia is the key feature of depression impacting how children’s brains are responding, at least in our study, rather than other common symptoms of depression.”For the new study, researchers performed a lab experiment involving more than 200 parents and children ages 7 to 11.The experiment was designed to see how parents’ anhedonic symptoms affect children’s brain responses to positive and negative feedback.“The idea is that if you have this risk factor of being less interested or less engaged or finding things less enjoyable, maybe that’s reflected in how your brain responds to environmental feedback,” said lead researcher Alana Israel, a doctoral student at Binghamton University, a branch of the State University of New York. “Children of parents who have higher levels of anhedonic depressive symptoms should show a reduced response while other depressive symptoms theoretically should not be as related to this specific brain response,” Israel explained in a news release.In the experiment, children were presented with two doors and asked to guess the one with a prize behind it. If they chose the right door, they won money; if they chose wrong, they lost money.Results showed that kids’ response to either winning or losing money was blunted if their parents had higher levels of anhedonic symptoms. “What that tells us is that there is something specific about parents’ anhedonia that may impact children’s neural responses,” Israel said. “It further specifies a group of children who might be at heightened risk for loss of interest or pleasure and lack of engagement, which is a core feature of depression.”Future research should investigate how family dynamics might change if parents with anhedonic symptoms receive treatment or start to feel better, the team said.Researchers said it’s also important to examine whether children’s responses to other sorts of feedback, like social feedback from peers, are also affected by parents’ depression.“There are researchers looking at interventions that are designed to increase positive mood, positive engagement and positive parent-child relationships,” Israel said. “It will be important to see if these findings can identify families who might be most likely to benefit from those types of interventions.”SOURCE: Binghamton University, news release, Dec. 4, 2025Copyright © 2025 HealthDay. All rights reserved.

We may finally know what a healthy gut microbiome looks like

Our gut microbiome has a huge influence on our overall health, but we haven't been clear on the specific bacteria with good versus bad effects. Now, a study of more than 34,000 people is shedding light on what a healthy gut microbiome actually consists of

The trillions of microscopic bacteria that reside in our gut have an outsized role in our healthTHOM LEACH/SCIENCE PHOTO LIBRARY We often hear talk of things being good for our microbiome, and in turn, good for our health. But it wasn’t entirely clear what a healthy gut microbiome consisted of. Now, a study of more than 34,000 people has edged us closer towards understanding the mixes of microbes that reliably signal we have low inflammation, good immunity and healthy cholesterol levels. Your gut microbiome can influence your immune system, rate of ageing and your risk of poor mental health. Despite a profusion of home tests promising to reveal the make-up of your gut community, their usefulness has been debated, because it is hard to pin down what defines a “good” microbial mix. Previous measures mainly looked at species diversity, with a greater array of bacteria being better. But it is difficult to identify particular communities of interacting organisms that are implicated in a specific aspect of our health, because microbiomes vary so much from person to person. “There is a very intricate relationship between the food we eat, the composition of our gut microbiome, and the effects the gut microbiome has on our health. The only way to try to map these connections is having large enough sample sizes,” says Nicola Segata at the University of Trento in Italy. To create such a map, Segata and his colleagues have assessed a dataset from more than 34,500 people who took part in the PREDICT programme in the UK and US, run by microbiome testing firm Zoe, and validated the results against data from 25 other cohorts from Western countries. Of the thousands of species that reside in the human gut, the researchers focused on 661 bacterial species that were found in more than 20 per cent of the Zoe participants. They used this to determine the 50 bacteria most associated with markers of good health – assessed via markers such as body mass index and blood glucose levels – and the 50 most linked to bad health. The 50 “good bug” species – 22 of which are new to science – seem to influence four key areas: heart and blood cholesterol levels; inflammation and immune health; body fat distribution; and blood sugar control. The participants who were deemed healthy, because they had no known medical conditions, had about 3.6 more of these species than people with a condition, while people at a healthy weight hosted about 5.2 more of them than those with obesity. The researchers suggest that good or bad health outcomes may come about due to the vital role the gut microbiome plays in releasing chemicals involved in cholesterol transport, inflammation reduction, fat metabolism and insulin sensitivity. As to the specific species that were present, most microbes in both the “good” and “bad” rankings belong to the Clostridia class. Within this class, species in the Lachnospiraceae family featured 40 times, with 13 seemingly having favourable effects and 27 unfavourable. “The study highlights bacterial groups that could be further investigated regarding their potential positive or negative impact [on] health conditions, such as high blood glucose levels or obesity,” says Ines Moura at the University of Leeds, UK. The link between these microbes and diet was assessed via food questionnaires and data logged on the Zoe app, where users are advised to aim for at least 30 different plants a week and at least three portions a day of fermented foods, with an emphasis on fibre and not too many ultra processed options. The researchers found that most of the microbes either aligned with a generally healthy diet and better health, or with a worse diet and poorer health. But 65 of the 661 microbes didn’t fit in. “These 65 bacteria are a testament to the fact that the picture is still more complex than what we saw,” says Segata, who also works as a consultant for Zoe. “The effects may depend on the other microbes that are there, or the specific strain of the bacterium or the specific diet.” This sorting of “good” versus “bad” bacteria has enabled the researchers to create a 0 to 1000 ranking scale for the overall health of someone’s gut microbiota, which is already used as part of Zoe’s gut health tests. “Think of a healthy gut microbiome as a community of chemical factories. We want large numbers of species, we want the good ones outnumbering the bad ones, and when you get that, then you’re producing really healthy chemicals, which have impacts across the body,” says team member Tim Spector at King’s College London and co-founder of Zoe. This doesn’t mean the ideal healthy gut microbiome has been pinned down, though. “Defining a healthy microbiome is a difficult task, as the gut microbiome composition is impacted by diet, but it can also change with environmental factors, age and health conditions that require long-term medication,” says Moura. “We really need to think about our body and our microbiome as two complex systems that together make one even more complex system,” says Segata. “When you change one thing, everything is modified a bit as a consequence. Understanding what is cause and effect in many cases can be very intricate.” Bigger studies are needed to tease out these links and cover more of the global population, says Segata. However, once we have established the baseline of your health and microbiome, it should become possible to recommend specific foods to tweak your gut bacteria, he says.

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