Mark Hernandez News

K-12 air quality research spotlighted by industry group

Anonymous — Wed, 04 Sep 2024 16:08:45 +0000

K-12 air quality research spotlighted by industry group Anonymous (not verified) Wed, 09/04/2024 - 10:08

Mark Hernandez's air quality research is being highlight by Chemical and Engineering News.

Hernandez is a professor in the Environmental Engineering Program and air quality expert.

The work being spotlighted by C&EN, which is a publication of the American Chemical Society, initially focused on reducing the spread of COVID-19 in Denver Schools during the pandemic. It later expanded beyond concerns of infectious diseases to helping to improve air quality in schools across the board.

Launched in 2022 with funding from the CDC, the project seeks to correlate air quality in classrooms with the number of student absences due to respiratory illness.

The study’s provided portable HEPA air purifiers to classrooms across Colorado. Hernandez and his team installed air quality monitors to measure how well the filters were performing. By the end of 2023, 369 schools were enrolled in the project and agreed to send the researchers anonymous data on student absences.

Read the full article at C&EN...

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Research shows air filters in classrooms improves overall ventilation and air quality

Anonymous — Mon, 19 Aug 2024 20:17:43 +0000

Research shows air filters in classrooms improves overall ventilation and air quality Anonymous (not verified) Mon, 08/19/2024 - 14:17

Mark Hernandez's air quality research is being highlight by Denver 9 News.

The work which initially focused on reducing the spread of COVID-19 in Denver Schools during pandemic is now expanding beyond concerns of just infectious diseases and helping to improve air quality in schools across the state.

Hernandez is a professor in the Environmental Engineering Program and air quality expert.

"We now have data from ventilation performance for buildings all over the state. The good news was, we found out a lot of our buildings and classrooms are high performing. They have really good air quality and they really didn’t need the air cleaners," Dr. Hernandez said. "Others are less performing and when we put those in, we found out they helped ventilation systems do their job."

Read the full story at 9News...

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Can air purifiers help keep kids in school? New study seeks to find out

Anonymous — Wed, 27 Sep 2023 19:42:51 +0000

Can air purifiers help keep kids in school? New study seeks to find out Anonymous (not verified) Wed, 09/27/2023 - 13:42

Engineers at CU Boulder kicked off a new project this month that aims to investigate whether improving classroom air quality with air purifiers can help students miss fewer school days. The study comes at a time when millions of students across the country are chronically absent from school, a worsening trend that could have large impacts on students’ academic performance.

Mark Hernandez, the SJ Archuleta Professor in the Department of Civil, Environmental and Architectural Engineering, is co-leading the project with researchers at the CU Anschutz Medical Campus with a $2.2 million grant the Centers for Disease Control and Prevention awarded this month.

Over the past four months, Hernandez and his team, including eight engineering students, helped install air quality monitors in 2,400 classrooms across Colorado’s K-12 schools. These monitors can provide teachers, school officials and researchers with real-time data on classroom temperature, humidity, CO2 and air pollutant levels.

Mark Hernandez (Credit: CU Boulder)

The team also helped install air cleaners with high-efficiency particulate air (HEPA) filters in tens of thousands of classrooms statewide. These commonly available air purifiers can effectively filter out air pollutants—such as particulate matter from vehicle exhaust and wildfire smoke—that can trigger negative respiratory reactions and remove airborne pathogens like the coronavirus. The team will compare student absenteeism rates in classrooms with air purifiers with those without.

“Linking positive student outcomes to affordable air quality interventions has yet to be done on a large epidemiological scale,” said Hernandez. “I am thankful our flagship engineering college and public health school was chosen by CDC to team up for this work as a national model.”

An epidemic of absenteeism

During the 2022–23 school year, over a third of Colorado K-12 students were chronically absent—defined as missing 10% of the school days in a year. That’s up from one in five students before the pandemic. �鶹��Ժ are absent from school for a myriad of reasons—bullying, transportation problems and financial hardship—and asthma stands out as the leading cause of absenteeism due to chronic illness.

Funded by Colorado’s Ryan Innovation Fund, Hernandez started testing air purifiers in Denver Public School (DPS) classrooms in 2020, in an effort to help reopen schools under better conditions during the pandemic.

“When the pandemic broke out, there were a lot of people introducing air purifiers in classrooms. But many of the purifiers weren't sized correctly, didn’t work well or were too loud. No one had systematically assessed the purifiers’ performance in actual educational settings at this scale” Hernandez said.

In 2021, Hernandez and his team installed air purifiers coupled with air quality monitors in 20 public elementary school buildings with funding from the Intel Corporation and the Carrier Company. Most of the schools are located along the I-25 and I-70 highways, and their proximity to high-traffic corridors and industrial zones increases students’ exposure to air pollution, which could worsen the effects of COVID-19. In some of these schools, more than 20% of the students have asthma.

Mark Hernandez (middle) and his students installed air quality monitors and purifiers in Colorado classrooms. (Credit: The Hernandez lab)

The pilot trial’s data showed that the purifiers, when working properly, were effective in improving classroom ventilation and reducing air pollutants. Impressed by the results, DPS funded Hernandez’s team to extend the program to 800 classrooms in 100 schools in 2021.

In 2022, Hernandez received a $5.5 million grant from the Colorado Department of Public Health and Environment to expand the work state-wide into a new program called Clean Air for Schools. The additional CDC grant will allow the team to continue monitoring air quality in Colorado classrooms and investigate if there is a connection between air purifier operations, ventilation performance and student attendance.

“Until COVID-19, nobody really did anything about air quality in classrooms except in response to extreme weather conditions. Many political leaders and agency decision-makers projected systemic air quality improvements to be too expensive,” Hernandez said.

An inexpensive, but powerful solution

Hernandez estimates that effectively reducing airborne particles in indoor air pollution with air purifiers would cost $65 per student, per classroom, per year.

“Installing a couple of air purifiers in a classroom is cheaper than a textbook, but schools are always strapped for money. Now we have data that shows these commonly available appliances, which don’t disrupt teaching, can be systematically prioritized. It’s well worth it in both the immediate and long term,” Hernandez said.

CU Boulder students set up air monitors in a classroom. (Credit: The Hernandez lab)

The project has a huge community and educational impact, Hernandez added. He is proud of the students and contractors who worked day and night to install the air monitors in thousands of classrooms over the past summer. Many of the young researchers working on the project are first-generation college students who come from communities disproportionately affected by air pollution and COVID-19. Studies have found that Black and Hispanic students have the highest asthma rates in the U.S.

“A few of my students actually attended these schools near the industrial zones, and they are able to give back to the community with their education,” Hernandez said. The diverse group of students will continue to track the data and analyze air quality’s impact on absenteeism using the new grant.

“While I’m an engineer, I’m also an educator. Through this project, I get to work with our engineering students and watch them increase their skills and competence and advance their educational potential while doing something good for the community. This is one of the most rewarding projects I've had in nearly 30 years here at CU,” Hernandez said.

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Hernandez discusses indoor air quality with Washington Post

Anonymous — Mon, 12 Jun 2023 17:57:11 +0000

Hernandez discusses indoor air quality with Washington Post Anonymous (not verified) Mon, 06/12/2023 - 11:57

The Washington Post is highlighting ways to keep air quality better indoors.

The outlet interviewed Mark Hernandez, who advocates for installing HEPA air cleaners in homes, especially now, with smoke from Canadian wildfires blanketing the northeastern United States.

“I look at them (air purifiers) as the seat belts for lungs," he said. Hernandez is helping to install filters in schools across the state in partnership with Colorado’s Clean Air for Schools program.

Hernandez is a professor in the Environmental Engineering Program and air quality expert.

Read the full article at the Washington Post.

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Three years in: What we’ve learned about COVID

Anonymous — Wed, 08 Mar 2023 15:57:36 +0000

Three years in: What we’ve learned about COVID Anonymous (not verified) Wed, 03/08/2023 - 08:57

Three years ago this week, Colorado recorded its first known cases of COVID-19. A week later, on March 12, CU Boulder announced its first positive case and quickly shifted to fully remote classes.

Meanwhile, researchers at CU and universities across the country jumped into action to learn everything they could about the virus, including how to test for and trace it; how to prevent its spread; and how to develop a vaccine to reduce its death toll.

Today, the pandemic and its impacts persist. While deaths in the U.S. are down significantly from peaks in previous years, in 2023 COVID-19 still kills more than 3,500 people each week and tens of millions still struggle with serious, lasting health effects.

Yet we know more than ever before about the virus and how to stop the next pandemic before it starts. Here’s a look at what CU Boulder researchers learned in year three.

COVID-19 is still a public health threat—but we can end it

While the U.S. federal public health emergency is set to expire on May 11, it is still a global public health threat and continues to disproportionately impact vulnerable populations around the world, according to 386 multidisciplinary experts from more than 100 countries and territories.

The authors of a Nature paper published in November recommended countries take a “vaccine-plus” approach to end the pandemic, including improved indoor air ventilation and filtration, increased masking, testing and treatment. They also emphasized a need to address the global inequities involved in access to vaccinations and healthcare.

“Unfortunately, COVID-19 is not yet over,” said Jose-Luis Jimenez, co-author of the study, distinguished professor of chemistry at CU Boulder and fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES). “But there are many things we can and should be doing about it here in the U.S. and across the world, and a high priority should be paying attention to and taking action by cleaning our indoor air.”

Jimenez and environmental engineering professor Shelly Miller are also co-authors on a recent publication in Clinical Infectious Diseases, which argues that the World Health Organization (WHO) dismissed scientists’ concerns at the start of the pandemic that the SARS-CoV-2 virus spreads through airborne particles (which float in the air like smoke), leading to avoidable consequences that can be learned from.

Read: COVID still a ‘dangerous global health threat.’ New international study spells out how we can end it

Take more care in drier air

Recent CU Boulder research has found that airborne particles carrying coronavirus can remain infectious for twice as long in drier air, in part because the saliva emitted with them serves as a protective barrier around the virus, especially at low humidity levels.

“It shows this virus can hang around for quite a while—hours, even,” said Mark Hernandez, senior author of the study and S. J. Archuleta Professor of Civil and Environmental Engineering.

This first-of-its kind study published in PNAS Nexus carries implications for mitigating transmission of coronavirus, as well as other viruses, in drier climates across the country, as well as in airplane cabins and during dry winter months worldwide.

Humidifying indoor spaces is expensive and inefficient, however, said Hernandez. Instead, adding high efficiency particulate air (HEPA) air filters, opening windows and improving ventilation are all easy and affordable measures anyone can implement.

Read: Tend to get sick when the air is dry? New research helps explain why

Given a moment to think, people choose to lower risks

When people simply take a moment to reflect on the consequences of their behavior, they tend to choose options that impose fewer risks on other people, according to research from Leaf Van Boven, professor of psychology and neuroscience.

The international study of 13,000 people, published in November in PNAS Nexus, was conducted at the height of the pandemic. Van Boven and his colleagues presented the global participants with hypothetical scenarios related to joining social gatherings during the pandemic, for which they had to decide to attend, cancel, or reduce capacity.

But before they did so, some participants were instructed to pause and practice a technique called “structured reflection.” Those in the structured reflection group were significantly more likely to err on the side of minimizing public health risks.

As COVID-19 restrictions lift, such personal responsibility will grow increasingly important.

“I would encourage everyone to develop a habit of asking themselves when they are considering any sort of large social gathering: What is the risk you might impose on other people, and is the benefit of the gathering worth the risk?” said Van Boven.

Read: Got the sniffles? Here’s how to make the right decision about holiday gatherings

�鶹��Ժ stepped up at CU and across the country

A study in BMC Public Health from researchers at CU Boulder, Colorado State University (CSU) and the Centers for Disease Control and Prevention (CDC) found that more than 90% of people on CU Boulder and CSU campuses wore masks correctly amid the pandemic during spring 2021. The new research indicates that students understood masks’ effectiveness, knew masking helped them take more classes in person and generally care about the health of others.

“The study supports the idea that masks are an effective, low-cost measure to reduce disease transmission and establishes masking as a viable way to reduce respiratory disease transmission on college campuses,” says Tanya Alderete, assistant professor in the Department of Integrative Physiology at CU Boulder and a principal investigator of the project.

Read: Vast majority of students were up for the mask

Germicidal ultraviolet light remains a useful tool

A study led by scientists at the Cooperative Institute for Research in Environmental Sciences (CIRES) and CU Boulder has helped shine a light on another approach to disinfecting our shared indoor air: germicidal ultraviolet light (GUV), which can inactivate airborne pathogens but also has potential to create an unhealthy indoor “smog.”

Published in Environmental Science & Technology Letters, the work found that after GUV disinfection, the amount of harmful secondary chemicals in indoor air have an impact, but are not so detrimental as to recommend against the use of GUV. This suggests that GUV can be used to fight COVID, as well as influenza and respiratory syncytial virus (RSV), in environments at high risk of virus transmission, such as emergency waiting rooms, restaurants and gyms.

Read: Destroying Coronavirus vs. Creating Indoor Smog

Working to prevent the next pandemic

CU Boulder virologist Sara Sawyer’s career was inspired by the defining pandemic of her childhood: the HIV/AIDS pandemic. Throughout the ongoing coronavirus pandemic, she has spent her time trying to prevent the next one.

Sawyer has spent the last 15 years gathering hundreds of samples from primate, rodent, bat and other mammalian species to better understand what evolution has taught them about how to live with viruses. In her lab at CU Boulder’s BioFrontiers Institute, she also employs cutting-edge genetic sequencing and lab techniques to better understand why when some viruses jump into new species, some succeed, and others fizzle out.

Her lab’s research has found that genetics plays a role, not only in how viruses spread within the same species, but also how they jump from species to species, including to people.

In September, she and her colleagues identified an obscure family of viruses, already endemic in wild African primates and known to cause Ebola-like symptoms in some monkeys, that is, as they put it, “poised for spillover” to humans. While no human infections have been reported to date, she urges the scientific community to be vigilant.

“COVID is just the latest in a long string of spillover events from animals to humans, some of which have erupted into global catastrophes,” Sawyer said. “Our hope is that by raising awareness of the viruses that we should be looking out for, we can get ahead of this, so that if human infections begin to occur, we’re on it quickly.”

Read: Virus Hunter, Preventing the Next Pandemic

Diet and lifestyle factors might reduce disease risks

Besides avoiding infection and reducing transmission, what can people do?

Feeding our gut microbes with healthy foods, spices and antioxidants, as well as addressing our stress and balancing physical activity with adequate recovery are some actions we can take to give ourselves a chance at less severe outcomes and full recovery following infection, said Barbara Demmig-Adams, professor of distinction and director of the EBIO Honors Program within the Department of Ecology and Evolutionary Biology.

Demmig-Adams is co-author on a study published last year in the American Journal of Lifestyle Medicine, detailing how the human body is predisposed to chronic, low-level inflammation—which puts us at a biological disadvantage when fighting off the virus that causes COVID-19.

Due to our bodies’ inflammatory responses, she notes that we should be just as careful about overexerting our bodies as not moving them enough. If you are actively sick or recently recovered, it may be wise to schedule in more rest and recovery time than anticipated.

Read: 4 easy ways to reduce your risk of severe COVID-19

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Tend to get sick when the air is dry? New research helps explain why

Anonymous — Thu, 23 Feb 2023 23:58:49 +0000

Tend to get sick when the air is dry? New research helps explain why Anonymous (not verified) Thu, 02/23/2023 - 16:58

Recent research from CU Boulder may have finally revealed why humans tend to get sick from airborne viral diseases more often in drier environments.

Published in December in PNAS-Nexus, the study found that airborne particles carrying a mammalian coronavirus closely related to the virus which causes COVID-19 remain infectious for twice as long in drier air, in part because the saliva emitted with them serves as a protective barrier around the virus, especially at low humidity levels.

The study carries major implications for not only the current COVID-19 pandemic but potentially for all infectious diseases transmitted by saliva-coated viruses. The research also further emphasizes the importance of managing indoor air filtration and ventilation to mitigate airborne disease spread, especially for buildings in arid states such as Colorado, dry enclosed environments such as airplane cabins and during dry winter months in temperate climates worldwide.

“The physics of the air in our buildings and the climate in which we live affect things that can make us sick and how long they persist. Now we have conservative indications of how long coronaviruses like the one that causes COVID-19 can stick around in the air and be an infectious disease threat,” said Mark Hernandez, senior author and S. J. Archuleta Professor of Civil and Environmental Engineering.

In 2020, Hernandez had a hunch that both relative humidity and saliva were important factors in the transmission of the novel virus sweeping the globe. He also happened to run the Environmental Engineering Microbiology and Disinfection Lab, one of the country’s only full-scale bioaerosol labs ready and able to take on the challenge at the start of the pandemic.

Professor Mark Hernandez and doctoral graduate Marina Nieto-Caballero stand inside a bioaerosol chamber in the Environmental Engineering disinfection laboratory at the Sustainability, Energy and Environment Complex (SEEC). Photo by Patrick Campbell/CU Boulder.

Civil engineers design and operate buildings in the U.S. to maintain an indoor relative humidity between about 40% and 60%. In the real world, however, these percentages vary more widely. In San Francisco for example, where Hernandez grew up, the relative humidity pushes a dewy 60%. In comparison, Colorado hovers at an arid 25%.

Unique bioaerosol lab, dedicated students made COVID research possible

As one of the first interdisciplinary bioaerosol labs established in the U.S., the Environmental Engineering Microbiology and Disinfection Lab at CU Boulder is home to one of the biggest bioaerosol chambers in the country at an academic institution. At about 350 cubic feet, it provides a large experimental space that realistically mimics the indoor environments people live, work and play in every day...Read more.

So they released virus-laden, airborne particles into several state-of-the-art, sealed chambers—the largest one about the size of a large bathroom—both with and without saliva, and at 25%, 40% and 60% relative humidity. They found the saliva acted as a protective mechanism for the virus regardless of the humidity level. At both 40% and 60% relative humidity, half of the airborne coronavirus particles were still infectious after aging for one hour in the chamber. But at 25% humidity, that time doubled: Half of the original particles released into the chamber remained infectious for two hours.

“It shows this virus can hang around for quite a while—hours, even. It's longer than a class, longer than the time you're in a restaurant, longer than the time you take to hang out in the cafe. An occupant may come in, spread coronavirus in the air, and leave. Depending on architectural factors, then someone else could walk into that space with potent doses still hanging around,” said Hernandez.

As the virus can remain infectious in the air longer than it takes most ventilation systems to remove it, additional air-focused mitigation measures such as filtration are required to reduce transmission, the study suggests.

“I hope this paper has an engineering impact in our buildings, for example, in schools and hospitals, so we can minimize the infectivity of these viruses in the air,” said Marina Nieto-Caballero, lead author, who earned her doctorate in the Hernandez bioaerosol lab in 2021 and is now a postdoctoral researcher at Colorado State University.

Colored sample media is used to demonstrate aerosolization of the particles in the chamber. Photo by Patrick Campbell/CU Boulder.

Marina Nieto-Caballero, CU graduate and now a postdoctoral researcher at Colorado State University, assesses the infectious potential of airborne murine coronavirus using computer aided microscopy. Photo by Patrick Campbell/CU Boulder.

Using saliva for science

Temperature, light and relative humidity can all affect how long a viral particle remains infectious, but until now, no study had accounted for the fluids that carry them. Yet people are always producing saliva and emitting tiny particles into the air every time they talk, laugh or even sing, said Hernandez.

The team used medical-grade fake saliva to mimic those particles and turned to chemistry professor Magaret Tolbert to examine samples of saliva-protected virus under a typical microscope on flat plates, as well as with a special microscope that measures them in air.

Together, they found it’s not the proteins in saliva—as hypothesized by other scientists—that allow the virus to persist so well in drier air, but its sugary carbohydrates that stabilize them. While many types of airborne particles, such as common salt particles, crystallize in lower relative humidity, the saliva particles became gelatinous, even glassy, said Tolbert.

The researchers suspect it is this physical state, somewhere between solid and liquid, that provides the virus extra protection and allows it to linger longer in dry air.

Hernandez hopes the findings can help open the door for more “messy” research using more realistic scenarios to better understand airborne particles.

“Let's get more real about how we test things in the lab. Let's use saliva. Let's use lung fluids. Let's use blood. It's scary, and it's more expensive. But without that data, we don't know,” said Hernandez

Research in dry climates, for dry climates

Coloradans are among the 100 million Americans who live in a dry climate and who could, as a result, be at increased exposure risk indoors for airborne viruses such as coronavirus.

While more research is needed, this study could partially explain why Colorado was one of 16 states with a "very high" rate of influenza-like illnesses last November, according to data from the Centers for Disease Control and Prevention.

But what can those of us who live or spend time in drier environments do?

While it may be worth increasing relative humidity indoors to at least 40%, humidifying indoor spaces is expensive and inefficient, said Hernandez.

“Instead, we can add simple, inexpensive air filters that will take particles out of the air faster. We can increase the ventilation rate, open windows, and make sure we get more fresh air through,” said Hernandez. “We've known this from the beginning, but this research gives us a target.”

Additional authors on this paper include: Odessa Gomez and Margaret Tolbert of CU Boulder; Shuichi Ushijima of CU Boulder and CIRES; Ryan Davis and Erik Huynh of Trinity University; Eddie Fuques of Oregon State University; and Alina Handorean of the Colorado School of Mines.

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Unique bioaerosol lab, dedicated students made COVID research possible

Anonymous — Thu, 23 Feb 2023 23:31:41 +0000

Unique bioaerosol lab, dedicated students made COVID research possible Anonymous (not verified) Thu, 02/23/2023 - 16:31

As one of the first interdisciplinary bioaerosol labs established in the U.S., the Environmental Engineering Microbiology and Disinfection Lab at CU Boulder is home to one of the biggest bioaerosol chambers in the country at an academic institution. At about 350 cubic feet (10 cubic meters), it provides a large experimental space that realistically mimics the indoor environments people live, work and play in every day.

While set up to study infectious airborne particles, this state-of-the-art facility is one of the safest places on campus, said Mark Hernandez, S. J. Archuleta Professor of Civil and Environmental Engineering and director of the lab. Equipped with top-tier indoor air ventilation and filtration, it receives 100% fresh air from outside the lab and undergoes 12 air changes per hour (ACH)—an industry gold standard.

Professor Mark Hernandez and doctoral graduate Marina Nieto-Caballero stand inside the 10-cubic-meters bioaerosol chamber used to study live airborne coronavirus persistence in the Environmental Engineering disinfection laboratory at the Sustainability, Energy and Environment Complex (SEEC). Photo by Patrick Campbell/University of Colorado.

But the most important part of the lab’s recent COVID-19 research was having the right people in the right place at the right time, said Hernandez.

Marina Nieto-Caballero had one year left in her doctoral program, one last chapter of her thesis yet to write, and a career-changing decision to make in 2020: Should she switch from studying bacteria and microbes to focusing on the virus that had come to dominate the world’s attention?

“It was very important to me to be able to have an impact during this pandemic,” said Nieto-Caballero.

Her gut decision to take this “hard left turn” was influenced by the timely presence of virologist and study co-author Eddie Fuques, who had come to the lab as a visiting researcher but could not return to his home country of Uruguay due to sudden travel restrictions. He stayed several extra months with the team and helped Nieto-Caballero pivot her research focus.

Odessa Gomez, one of Hernandez’s previous students who now works at the Colorado Department of Public Health and Environment as an Indoor Air Quality Assessment Program supervisor, also came back to assist with this project and other COVID-related research.

Tend to get sick when the air is dry? New research helps explain why

This team of CU Boulder researchers, alumni and visiting collaborators worked for 18 straight weeks, on weekdays and weekends, day and night, to complete this work in 2020.

For their recent study published in PNAS-Nexus, the team used murine hepatitis virus (MHV), a coronavirus that is very closely related to its pathogenic human counterpart SARS-CoV-2—however, it cannot infect humans. MHV is now a widely accepted model for pathogenic human viruses in scientific settings. At this CU Boulder engineering-based disinfection lab, MHV is grown on mouse brain tumor cells in a secure and safe laboratory space.

While maintaining a cozy room temperature of 71.6 degrees F (22 C), the researchers sprayed droplets of the virus mixed with artificial saliva into the large, sealed chamber, closely mimicking what humans release when we breathe and speak. Fans were used to mix the particles within the chamber, as the researchers took measurements of the particles while they floated around for two hours. In their data, they also accounted for the particles that had landed on the wall, floor and ceiling of the chamber. After each testing session, the sealed chambers were also zapped with ultraviolet light (UV) so that no infectious particles remained.

Specialized equipment placed inside the sealed chambers collected samples, which were then tested for infectious virus, and finally, visually interpreted by researchers with a computer aided high-resolution microscope. While healthy cells created a consistent pattern of small dots across the screen, infected cells looked pulled apart, ravaged.

“That's what it does when it gets in your brain or your lungs,” said Hernandez. “When you see that, it is remarkable—the damage that the virus can do.”

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CU Boulder scientists shine a light on what comes up when you flush

Anonymous — Thu, 08 Dec 2022 23:17:58 +0000

CU Boulder scientists shine a light on what comes up when you flush Anonymous (not verified) Thu, 12/08/2022 - 16:17

Thanks to new CU Boulder research, scientists see the impact of flushing the toilet in a whole new light—and now, the world can as well.

Using bright green lasers and camera equipment, a team of CU Boulder engineers ran an experiment to reveal how tiny water droplets, invisible to the naked eye, are rapidly ejected into the air when a lid-less, public restroom toilet is flushed. Now published in Scientific Reports, it is the first study to directly visualize the resulting aerosol plume and measure the speed and spread of particles within it.

These aerosolized particles are known to transport pathogens and could pose an exposure risk to public bathroom patrons. However, this vivid visualization of potential exposure to disease also provides a methodology to help reduce it.

“If it's something you can't see, it's easy to pretend it doesn't exist. But once you see these videos, you're never going to think about a toilet flush the same way again,” said John Crimaldi, lead author on the study and professor of civil, environmental, and architectural engineering. “By making dramatic visual images of this process, our study can play an important role in public health messaging.”

Researchers have known for over 60 years that when a toilet is flushed, solids and liquids go down as designed, but tiny, invisible particles are also released into the air. Previous studies have used scientific instruments to detect the presence of these airborne particles above flushed toilets and shown that larger ones can land on surrounding surfaces, but until now, no one understood what these plumes looked like or how the particles got there.

Understanding the trajectories and velocities of these particles—which can transport pathogens such as E. coli, C. difficile, noroviruses and adenoviruses—is important for mitigating exposure risk through disinfection and ventilation strategies, or improved toilet and flush design. While the virus that causes COVID-19 (SARS-CoV-2) is present in human waste, there is not currently conclusive evidence that it spreads efficiently through toilet aerosols.

“People have known that toilets emit aerosols, but they haven't been able to see them,” said Crimaldi. “We show that this thing is a much more energetic and rapidly spreading plume than even the people who knew about this understood.”

The study found that these airborne particles shoot out quickly, at speeds of 6.6 feet (2 meters) per second, reaching 4.9 feet (1.5 meters) above the toilet within 8 seconds. While the largest droplets tend to settle onto surfaces within seconds, the smaller particles (aerosols less than 5 microns, or one-millionth of a meter) can remain suspended in the air for minutes or longer.

It’s not only their own waste that bathroom patrons have to worry about. Many other studies have shown that pathogens can persist in the bowl for dozens of flushes, increasing potential exposure risk.

“The goal of the toilet is to effectively remove waste from the bowl, but it's also doing the opposite, which is spraying a lot of contents upwards,” said Crimaldi. “Our lab has created a methodology that provides a foundation for improving and mitigating this problem.”

Aaron True, postdoctoral researcher (left), and John Crimaldi pose for a photo with the equipment.

A powerful green laser helps visualize the aerosol plumes from a toilet when it’s being flushed. Photos by Patrick Campbell/CU Boulder.

Not a waste of time

Crimaldi runs the Ecological Fluid Dynamics Lab at CU Boulder, which specializes in using laser-based instrumentation, dyes and giant fluid tanks to study everything from how odors reach our nostrils to how chemicals move in turbulent bodies of water. The idea to use the lab’s technology to track what happens in the air after a toilet is flushed was one of convenience, curiosity and circumstance.

During a free week last June, fellow professors Karl Linden and Mark Hernandez of the Environmental Engineering Program, and several graduate students from Crimaldi’s lab joined him to set up and run the experiment. Aaron True, second author on the study and research associate in Crimaldi’s lab, was instrumental in running and recording the laser-based measurements for the study.

They used two lasers: One shone continuously on and above the toilet, while the other sent out fast pulses of light over the same area. The constant laser revealed where in space the airborne particles were, while the pulsing laser could measure their speed and direction. Meanwhile, two cameras took high resolution images.

The toilet itself was the same kind commonly seen in North American public restrooms: a lid-less unit accompanied by a cylindrical flushing mechanism—whether manual or automatic—that sticks up from the back near the wall, known as a flushometer style valve. The brand-new, clean toilet was filled only with tap water.

They knew that this spur-of-the-moment experiment might be a waste of time, but instead, the research made a big splash.

“We had expected these aerosol particles would just sort of float up, but they came out like a rocket,” said Crimaldi.

The energetic, airborne water particles headed mostly upwards and backwards towards the rear wall, but their movement was unpredictable. The plume also rose to the lab’s ceiling, and with nowhere else to go, moved outward from the wall and spread forward, into the room.

The experimental setup did not include any solid waste or toilet paper in the bowl, and there were no stalls or people moving around. These real-life variables could all exacerbate the problem, said Crimaldi.

They also measured the airborne particles with an optical particle counter, a device that sucks a sample of air in through a small tube and shines a light on it, allowing it to count and measure the particles. Smaller particles not only float in the air for longer, but can escape nose hairs and reach deeper into one’s lungs—making them more hazardous to human health—so knowing how many particles and what size they are was also important.

While these results may be disconcerting, the study provides experts in plumbing and public health with a consistent way to test improved plumbing design and disinfection and ventilation strategies, in order to reduce exposure risk to pathogens in public restrooms.

“None of those improvements can be done effectively without knowing how the aerosol plume develops and how it's moving,” said Crimaldi. “Being able to see this invisible plume is a game-changer.”

Additional authors on this publication include: Aaron True, Karl Linden, Mark Hernandez, Lars Larson and Anna Pauls of the Department of Civil, Environmental, and Architectural Engineering.

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Clearing the Air on COVID-19: Duo Campus Project Aimed at Keeping Schools Open

Anonymous — Wed, 20 Apr 2022 18:35:17 +0000

Clearing the Air on COVID-19: Duo Campus Project Aimed at Keeping Schools Open Anonymous (not verified) Wed, 04/20/2022 - 12:35

The classrooms of Barnum Elementary School in Denver echo with the chatter of students and the instruction of teachers. The white, waist-high, curved machine in the corner is quiet as can be.

The machine, which looks like a less-complicated R2D2, contains a NASA-designed HEPA filter and is part of a cross-campus initiative between the University of Colorado Boulder and the Colorado School of Public Health (ColoradoSPH) at the CU Anschutz Medical Campus. The project’s goal is to test and clean the air in classrooms across the state, preventing the spread of SARS-CoV-2 and keeping the state’s schools open.

Reading the air

Mark Hernandez, PE, PhD, S. J. Archuleta professor of environmental engineering at CU Boulder, is leading the air-filtration part of the initiative that monitors the biomatter in classroom air. The system, designed at CU Boulder, is borrowed from a military technology that was used for bioterrorism or biological warfare assessment.

“This crossed over in the civilian sector for indoor assessment,” Hernandez said. “And prior to COVID-19, it was used for flood-damaged buildings. So we go into the public schools, characterize the ventilation performance and look at that biological quality of what the kids are breathing in school.”

The monitoring system can separate inorganic matter from biological matter in the air, helping assess the levels of viruses, such as RSV, influenza, COVID-19, tuberculosis, whooping cough and COVID-19. Hernandez’s lab has been researching the characterization and control of airborne microorganisms for almost 25 years. The study uses the large bioaerosol chamber in Hernandez's lab.

“We are using classic methods for culturing mammalian viruses as well as emerging instrumentation from the Colorado tech sector that helps them characterize the identity, distribution and infectious potential of indoor airborne microorganisms — notably including coronavirus,” Hernandez said.

Testing student masks

After seeing Hernandez’s project featured on 9News, May Chu, PhD, a clinical professor in epidemiology at the ColoradoSPH, reached out. Chu and her team have spent the last year successfully implementing a COVID-19 testing program in Denver Public Schools and local universities. The project uses disposable face coverings (masks) with a polyvinyl alcohol strip inside, right under the wearer’s nose, used to detect SARS-CoV-2.

�鶹��Ժ who opt to participate in the study – which is currently testing at seven college campuses representing 73% of all the registered college students in the state and at four K-12 schools – pick up masks in the morning and return them three to four hours later. Once the student hands in their mask, the ColoradoSPH team works with COVID Check Colorado to administer a nasal swab PCR test to detect SARS-CoV-2. The school gets the results of the nasal swab testing in the evening each day.

The study, funded by the World Health Organization, also includes the University of Leicester in England. Using the strip, researchers can determine whether participants are COVID-19-positive, even those who are asymptomatic or test negative through a nasal swab PCR test.

While the ColoradoSPH team has received overwhelming support from schools that welcomed the help to test students, they have been slow to find new participants, as many are experiencing burnout with all COVID-related activities and discussions.

“Our theory is that someone could be infected with SARS-CoV-2 in their nose, but we want to understand how much they’re actually exhaling the virus, because it's the exhalation that makes the person infectious,” Chu said. “If it stays in your nasal cavity and is not detected by the strips in a mask, then there's a good chance you're really not at high risk of infecting other people. We believe there is a difference in being PCR-positive and being actually of some risk.”

Keeping levels at bay

While the machines testing and filtering the air from Hernandez’s project give easy-to-read levels that schools can monitor independently, the ColoradoSPH team is working to compare the levels of SARS-CoV-2 in the air with the mask and positivity rates from her study. The ColoradoSPH study is seeking evidence that may lead to delineating when people should or should not wear a mask.

“If it stays in your nasal cavity and is not detected by the strips in a mask, then there's a good chance you're really not at high risk of infecting other people. We believe there is a difference in being PCR-positive and being actually of some risk.” – May Chu, PhD

“These students are in congregate situations all day, in dorms, at parties, shouting at sporting events, etcetera. So we hope to determine the ways in which they’re transmitting the virus or not,” Chu said.

“We want to find out the metrics that we can use to measure a classroom by the level of infectivity in the students and teachers,” Chu said. “This will allow schools to stay open because they’ll be able to measure and test the viral content in the air, and hopefully meet the metrics of low transmission, low particles or have high particles with fast removal.”

“This partnership between the ColoradoSPH and CU Boulder is so important,” Hernandez said. “We are interfacing building science and engineering with epidemiology, which we have never done before.”

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COVID-19 has spurred investments in air filtration for K-12 schools – but these technologies aren’t an instant fix

Anonymous — Tue, 24 Aug 2021 22:01:08 +0000

COVID-19 has spurred investments in air filtration for K-12 schools – but these technologies aren’t an instant fix Anonymous (not verified) Tue, 08/24/2021 - 16:01

The COVID-19 pandemic has brought increased attention to indoor air quality and the effect that ventilation has on reducing disease transmission in indoor spaces. A recent infrastructure survey reported that of the nearly 100,000 operating public school buildings across the U.S., more than a third have an immediate need for upgrades to the ventilation systems that help control indoor air quality and the spread of “aerosols.”

Aerosol is the term used to describe the millions of microscopic particles that float in air – both indoors and out. People constantly inhale and exhale aerosols, some of which include allergens, particles from automobile exhaust, wildfire ash and microbes.

Our University of Colorado environmental engineering team has been studying the microbiological components of indoor air, called “bioaerosols”, for more than 25 years. We have surveyed the ventilation systems of hundreds of K-12 classrooms, health care facilities and restaurants. And we have provided facilities managers with affordable plans to improve indoor air quality.

Our own work as well as others’ has found that many classrooms are unfortunately poorly ventilated, and that better ventilation can reduce student absences due to illness – both during a pandemic and more normal times.

After surveying the installation of air filtration systems over the past year, we found that they can significantly improve air quality in classrooms by lowering aerosol levels, which in turn lowers COVID-19 transmission risk. But effective installation is key.

A new age of filtration

As the pandemic continues to highlight the need for better ventilation and indoor air quality, many academic institutions, government agencies, nongovernmental organizations and professional building science societies have been promoting better building-management practices to improve school ventilation.

Some building scientists have called for bringing the ventilation conditions in schools up to the levels prescribed for medical clinics. Unfortunately, the infrastructure investments required for that level of upgrade are well out of practical reach for many public buildings: Between 2008 and 2017 alone, state capital funding for schools was cut by $20 billion, or 31%.

In the absence of funding for major building upgrades, simple in-room filtration technologies have been installed in some schools to improve ventilation in classrooms where many students spend their days in close quarters. However, these filters have only been deployed in a small fraction of public schools across the country.

This technology, called high efficiency particulate air (HEPA) filtration, was born in the aerospace industry more than 50 years ago. HEPA filtration has been proved to efficiently remove microscopic airborne particles – including respiratory viruses – from air in higher occupancy spaces like classrooms.

Over the past few years, a new generation of HEPA filters have emerged from the U.S. commercial sector. These filters are more compatible with educational settings and less intrusive than their research-grade counterparts that are commonly used in the aerospace and pharmaceutical sectors, where “clean rooms” are needed. These latest models include improvements like multidirectional intake, reduced noise, lower power requirements, better durability and relatively small footprints.

HEPA filters have also become more widely used over the past couple of decades in homes in response to the recognition of rising asthma rates among children. But until the COVID-19 pandemic, they were rarely used in public school settings.

Bringing fresher air to classrooms

Over the 2021 spring academic semester, our team installed hundreds of new HEPA filters in public elementary classrooms in Denver, Colorado, the largest metropolitan school district in the Mountain West. These upgrades were possible due to a recent industry-university cooperative effort between the University of Colorado, the Intel foundation and the Carrier Corporation, a multinational ventilation equipment company. Together, these organizations contributed more than $500,000 for large-scale ventilation assessments, HEPA filter installations and other air quality improvements for Denver-area schools.

University of Colorado, Boulder, professor Mark Hernandez, engineering student Ricardo Reyes and architecture student Halle Sago take microbial counts on a classroom desk in Boulder in spring 2021.Glenn Asakawa/CU Boulder, CC BY-ND

A yet-unpublished poll of teachers in many of those classrooms overwhelmingly reported that this new generation of HEPA filters were welcome and easy to accommodate in their classrooms.

But like all engineering solutions, air filter effectiveness depends on proper installation. Our team’s field studies demonstrate that a simple “plug-and-play” approach will not address the complicated reality of aerosol exposures in densely occupied classrooms. In many situations, we have found HEPA filters that were undersized and placed inappropriately – such as facing a wall or in a remote corner – and sometimes not even turned on.

Networks of HEPA filters need to be thoughtfully installed, and the process must take into consideration other factors such as existing ventilation system performance, ceiling height, desk layouts and the presence or absence of ceiling fans. HEPA filters can only work up to their full potential if schools have the right number of them, they are the appropriate size and are placed in optimal positions.

The best HEPA filter installations consider details like student seating charts, high traffic areas and other variables based on student behaviors. Fortunately, building facility managers and custodial staff can be trained, with modest time investment, to install, operate and maintain HEPA filters in classrooms, with minimal distraction to teachers.

Air quality improvements are an investment in health and education

A 2020 review on indoor air quality strategies estimates that an individual HEPA filter, sized for elementary school classrooms with average energy use, costs about $361. This is consistent with our team’s experience in the Denver Public Schools system, where we typically installed at least two units per classroom at a cost of less than $800 per room. We estimate that this is roughly equal to the cost of one extra textbook per student over an academic year. In our opinion, that is well worth the potential improvement in indoor air quality in classrooms.

In-room HEPA filtration is a long-term investment that supplements existing ventilation systems. And though COVID-19 was the impetus for the installation of many HEPA filters, they are effective for far more than just reducing exposures to airborne viruses. Well-maintained and properly functioning filtration systems also reduce exposure to wildfire ash that can penetrate buildings, as well as allergens and other unwanted particles like automobile exhaust, tire detritus and construction dust.

But even the best indoor HEPA filtration cannot guarantee protection from airborne respiratory threats in schools. HEPA filters are effective only as part of an integrated approach. Ultimately, masks, distancing and reducing the number of students packed into tight spaces will determine how well students are protected from COVID-19.

HEPA filters are the modern analogy of “seat-belts” for indoor air quality in the age of COVID-19. If fitted correctly, they can only help lower the exposures to COVID-19 and other aerosols that students experience during their school days.

[Understand new developments in science, health and technology, each week.Subscribe to The Conversation’s science newsletter.]

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Reading the air

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Keeping levels at bay

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