Air Quality Matters

This week, we sit down with Jason Wolfson, President of AirCycler, who has spent over two decades at the centre of residential indoor air quality and energy efficiency standards in North America, to explore a question that fundamentally challenges how we think about home ventilation: What if the single biggest barrier to delivering healthy indoor air in homes isn't our lack of scientific knowledge or technology—but our complete failure to recognise that the past 25 years of ventilation strategy has been based on educated guesses using bedrooms and square footage.

Key Topics Discussed:

• From Build America to Controlled Ventilation: The DOE's Build America program in 1995 under President Clinton was the epicentre of everything that followed. Homes were made airtight to save energy, reduce carbon and cut dependence on foreign oil. Insulation improved. Ducts were sealed. But then the problem became obvious. Humans are polluters. Homes had been naturally ventilated through leaks. That worked fine. You used to walk by a window and feel a draft in winter. But that was energy loss. When that energy loss was eliminated, controlled fresh air became essential. AirCycler developed the first commercial controller in 1999 that watched the thermostat and ensured minimum runtime on the blower so homes got a measured amount of air instead of relying on random leaks.
• The Bedroom and Square Footage Problem: For 25 years, ASHRAE 62.2 has determined ventilation rates based on a formula using bedrooms and square footage. Bedrooms plus one approximates occupancy. Square footage adds a factor for the size of the home. That formula has been the foundation of residential ventilation in the United States. But it is not a feedback system. It is a guess. Jason compares it to heating a home without being able to measure temperature. You would calculate the heat loss, install a furnace with double the capacity, and run it half the time. It might work on average, but you would be overheating or underheating constantly. That is exactly what has been happening with ventilation. Most of the time homes are overventilating, wasting energy. During high pollution events like cooking or large gatherings, homes are underventilating.
• The Only Question That Matters: Jason has one ask from the scientists at the IEA EBC Annex 101 conference. Tell me when to turn the ventilation on. That is it. What are the stressors to react to? What is the base rate to handle pollutants we cannot measure? Industry is already shipping products with responsive controls. They are reading peer reviewed literature and making engineering decisions. But they are not building scientists. They need guidance. If the academic and standards community does not adapt quickly enough, industry will outrun them. Local code officials will see what works in practice and adopt it into local codes. ASHRAE 62.2 and Annex 101 could become irrelevant. It happened in the computer industry in the 1980s when Intel outpaced IEEE on bus standards. It could happen here.

GUEST:

Jason Wolfson - https://www.linkedin.com/in/jason-wolfson-b3a5045/

AirCycler - https://www.aircycler.com/

IEA EBC Annex 101 - https://annex101.iea-ebc.org/

The Air Quality Matters Podcast in Partnership with

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Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Lindab (https://www.lindab.ie/) - S&P UK (https://www.solerpalau.com/en-uk/)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) - Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast) - Farmwood (https://farmwood.co.uk/) - iE Electronics (https://www.eielectronics.ie/) and iAir Group (https://iair-group.com/)

Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we sit down with Rebecca Coates, Head of Radon Projects at PropertEco. Who has spent over 16 years managing radon testing and mitigation programs across the UK, to explore a question that fundamentally challenges how we think about indoor air quality and home safety: Our complete failure to recognise that for the price of a family meal out, any homeowner can test their property, that remediation is not tearing up floors or spending tens of thousands, but drilling one hole from outside and installing a fan in an afternoon, and that until we treat radon mitigation like servicing a boiler, something routine and well understood, over 1,100 people a year in the UK alone will continue to die from lung cancer caused by a gas they never knew was there?

Key Topics Discussed:

• What Radon Remediation Actually Looks Like: Radon remediation is not about cleaning contaminated materials or tearing up your home. Once the gas is gone, the problem is solved. The most common solution is a radon sump system installed from outside the building. A small hole is core drilled beneath the foundations, a void is excavated to create a point of low pressure, and pipework with an inline fan draws radon out from beneath the building and discharges it safely above roof level. The work is completed in a day. It costs around three to three and a half thousand pounds for a standard residential property. No one needs to leave their home. There is no dust inside. It is not disruptive. And in 95 percent of cases, it works first time.
• The Suspended Floor Challenge: Suspended timber floors are more complicated than solid floors. You have a ready made void running under the whole footprint of the building. Sometimes extracting from that void works beautifully. Sometimes it makes levels worse by drawing more radon up through the floorboards. There is no one size fits all solution. It can require trial and error. Sometimes the answer is to ignore the floor void completely and drill deeper beneath the building to create a sump at a lower level. Suspended floors bring moisture risk, thermal performance, air movement and radon together in ways that require multidisciplinary expertise. Many radon specialists come from property preservation backgrounds precisely because of this complexity.
• Ventilation as a First Line of Defence: Where radon levels are moderate, improving ventilation can be enough. Radon is a gas. Dilution works. Somewhere between 50 and 75 percent of homes do not have adequate ventilation. Fixing that can solve radon problems and bring co benefits for damp, mould and condensation. Positive input ventilation can work by gently increasing air pressure in the building to inhibit radon ingress and by diluting what is already there with fresh filtered air from outside. For low to moderate radon levels, this can be a very effective first step before considering a sump system.
• The Awareness Gap and the Path Forward: The biggest problem is that people do not know what they do not know. Carbon monoxide awareness has grown dramatically over the last two decades. Most homes now have a carbon monoxide alarm as standard. Considerably fewer people die each year from carbon monoxide poisoning than radon induced lung cancer. Yet radon remains invisible in public consciousness. The UK has one of the best radon maps in the world. Testing costs about fifty pounds. Remediation is straightforward. But unless the message reaches the man on the street, nothing changes. Social housing and schools are starting to take this seriously. The missing piece is the homeowning population. Radon testing should be as routine as an MOT on your car. You spend far more time in your house than your car. It is a one off cost to know whether the environment where your family spends 90 percent of their lives is safe.

GUEST:

Rebecca Coates - https://www.linkedin.com/in/rebeccacoates-radon-advice/

https://www.linkedin.com/in/rebecca-coates-radon/

https://properteco.co.uk/

https://radonassociation.co.uk/

https://www.ukradon.org/information/ukmaps

The Air Quality Matters Podcast in Partnership with

Mann + Hummel https://www.mann-hummel.com/en.html Particles Plus https://particlesplus.com/

Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Lindab (https://www.lindab.ie/) - S&P UK (https://www.solerpalau.com/en-uk/)

The One Take Podcast in Partnership with

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Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we sit down with Jihyun Park, associate professor in the Department of Architecture at Ewha Womans University in South Korea, Vice Director of the EWA Global Institute for Sustainable Partnerships and Empowerment, and founder and CEO of Atlasen, a venture company specialising in indoor environmental diagnostics, smart sensing and performance based management solutions, to explore a question that fundamentally challenges how we think about building performance and post occupancy evaluation.

Key Topics Discussed:

• From Architecture Practice to Building Performance: Jihyun spent over seven years working as an architectural designer in Korea, designing everything from office buildings to dormitories. But even while working in practice, she was troubled by a fundamental question. After a building was handed over, she had no idea whether it was actually a good building or not. Designers used formal references, copied details and systems from previous projects, but never knew if those systems worked in the real world. This gap between design intent and actual performance drove her into research. She wanted to understand not just how buildings were designed, but how they actually performed once people occupied them. That curiosity led her to pursue a PhD in building performance evaluation at Carnegie Mellon and eventually to founding Atlasen.
• Korea's Indoor Air Quality Evolution: Korea has had indoor air quality regulations for over 30 years, but the standards were relatively loose compared to North America. After COVID, everything changed. People became intensely interested in indoor air quality, driven not only by the pandemic but also by particulate pollution from China and increasing cases of skin conditions linked to toxic building materials. Before COVID, buyers wanted luxurious imported materials. Now they want healthy products. Younger generations are willing to pay more for healthy buildings. The shift has been dramatic and sustained. Energy was the focus. Now health and wellness are driving decisions in the built environment.
• Founding Atlasen and Building Your Own Sensors: Jihyun founded Atlasen because she wanted to integrate indoor environmental quality evaluation into building performance assessment. She had worked with Korea's electric power company, but the focus was entirely on energy savings. She believed energy efficiency should never come at the expense of occupant comfort and satisfaction. She wanted real time post occupancy evaluation combined with occupant surveys. But the equipment available was either too bulky, too expensive, or not accurate enough. So she built her own. She is now on the fourth generation of her in house sensor, which measures 15 different parameters including 10 air quality metrics covering particulates, carbon dioxide, carbon monoxide, formaldehyde, nitrogen dioxide, temperature and humidity. The sensors are small, invisible, accurate and used in projects across Korea, Canada and Hong Kong.
• The WELL Platinum Breakthrough: Jihyun led Korea's first WELL Core and Shell Platinum certification for a major mixed use development in Gangnam, Seoul. The project included two buildings with hotels, retail and office space, and housed some of the world's leading global companies. It is one of the most expensive buildings in the Gangnam area. The reason she got the project was simple. Other companies said they did not know how to do it and could not do it. She said she could. The building was already constructed and occupied for more than five years.

GUEST:

Jihyun Park https://www.linkedin.com/in/jihyun-park-3a70b212/

Atlasen - http://atlasen.com/?lang=en

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Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we sit down with Ciarán Cuffe, co-chair of the European Green Party and former rapporteur on the landmark revision of the Energy Performance of Buildings Directive, to explore a question that fundamentally challenges how we think about European policy and the built environment: What if the single biggest barrier to transforming our buildings isn't our lack of scientific knowledge or technology—but our complete failure to recognise that the most ambitious building legislation in European history was negotiated through late night deals, diplomatic trilogues, and careful political capital management, and that unless we understand how policy actually gets made, keep decision makers accountable during implementation, and translate technical directives into language that resonates with families worried about healthy homes, even the most groundbreaking legislation will fail at the national level?

Key Topics Discussed:

• From Architecture to the Brussels Machine: Ciarán brings a rare perspective, moving from architecture and local government in Dublin to national politics and finally to the European Parliament, where he landed what he calls a policy wonk paradise. As rapporteur for the EPBD recast, he spent two-thirds of his final two years in Europe negotiating what would become the most ambitious building law the continent has ever seen. The Greens threw everything at securing this file during the auction process for committee assignments. They didn't think they would get it, but they did. And it became the centrepiece of the European Green five years, alongside the European Climate Law and over 20 interconnected pieces of legislation covering everything from maritime fuels to energy trading.
• Inside the Trilogues: European policymaking is not just about the parliament. It is about three institutions: the European Parliament, the Council of Member States, and the European Commission. Ciarán spent countless hours in meetings with Commission officials from DG Energy, attending Council meetings in Luxembourg where energy ministers gathered, and working the sidelines to convince national teams that specific provisions would work for Sweden, for Malta, for Cyprus. The final deals happened in late night trilogues, where representatives from all three bodies sat in a room with pieces of paper, writing down numbers and asking, can we live with a 16 percent energy reduction by 2030? People were on the phone back to ambassadors, back to capitals. Eventually, you get a deal done. But within a complex technical document, you win in some areas and lose in others.
• The Affordability Backlash: Almost immediately after the recast was agreed, there was a political backlash on affordability. In Italy, Salvini, the Minister for Transport, declared that Brussels was going to take your home. It became a huge story. Ciarán and his team had to do outreach to major Italian newspapers like Sole 24 Ore to clarify that no, Brussels was not taking anyone's home, and in fact, Brussels would supply much of the money required for deep retrofits. The pushback showed that the directive had been pushed about as far as politically possible. If there had been no reaction, it would have meant they hadn't been ambitious enough.
• Indoor Environmental Quality Enters the Directive: One of the most significant achievements of the recast is the embedding of indoor environmental quality as a fundamental pillar of building performance. This shift, recognised globally by the indoor air quality movement, moves buildings from being seen as units of energy to being seen as homes. Ciarán believes the pandemic helped make the case. High mortality rates in northern Italy, in overcrowded urban areas with poor outdoor and indoor air quality, made it stunningly obvious that we needed to focus on the quality of the spaces where people spend most of their lives. Many of his colleagues in Brussels were living in small apartments with no balconies, no private outdoor space. Improving indoor air quality became not just a health issue, but an equity issue.
  
  GUEST:
  
  Ciarán Cuffe
  
  https://www.linkedin.com/in/ciarancuffe/The Air Quality Matters Podcast in Partnership with
  
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  Zehnder https://www.zehndergroup.com/en
  
  Charity Partner - https://www.saferairproject.org/

This week, we sit down with José Luis Gutiérrez Villanueva, a specialist radon measurement advisor at Radanova, member of the Commission on Radon Communication at the Spanish Professional Association of Physicists, and deeply involved in standards across Europe, to explore a question that fundamentally challenges how we think about indoor air quality and radiation protection: What if the single biggest barrier to protecting people from radon exposure isn't our lack of scientific knowledge or technology—but our complete failure to recognise that the only way to know your radon level is by measuring it, that no two buildings are the same, and that the invisible nature of this radioactive gas means millions of people are unknowingly breathing air that significantly increases their risk of lung cancer every single day?

Key Topics Discussed:

• The European Directive That Changed Everything: Since 2014, when the new European Directive on Radiation Protection was approved, all 27 member states now have legislation in place with reference levels for radon. For the first time in the history of radiation protection in Europe, every country must have a number in their national legislation. This is a massive game changer. Before that, there were only recommendations. Some countries followed them, others did not. Now there is a legally binding reference level, and this has moved everything forward.
• What Is Radon and Why Does It Matter: Radon is a naturally occurring radioactive noble gas that comes from the decay of uranium in soil and rock. It is everywhere. Outdoors, levels are usually very low, but indoors, radon can accumulate to dangerous concentrations. When you breathe radon, the gas itself is inert and exhaled, but during its journey through your lungs, radon decays into radioactive polonium, which attaches to lung tissue and emits alpha particles. These alpha particles have enough energy to damage DNA, and over years of continuous exposure, this damage accumulates and significantly increases the risk of lung cancer. After smoking, radon is the second leading cause of lung cancer.
• How Passive Radon Detectors Work: Passive radon detectors use a special plastic called CR39 inside a holder. Radon gas diffuses into the holder, and when radon decays, it emits alpha particles that create microscopic tracks in the plastic. After exposure, the detector is returned to the lab where the plastic undergoes chemical etching. The etching process enlarges the tracks so they can be counted under a microscope. The lab counts the number of tracks per square millimetre, applies a calibration factor, and calculates the radon exposure. This is then divided by the exposure time to give a result in becquerels per cubic metre.
• Why You Cannot Predict Radon Without Measuring: You cannot compare your home with your neighbour's home. Even if you live in detached houses next to each other, your radon levels can be completely different. Radon levels can vary dramatically within the same property, from room to room, and over time. Weather, soil moisture, air pressure, ventilation, and building characteristics all affect radon. One home on top of a hill might see radon drop when it rains, while a home in the valley below sees radon increase. Radon levels can fluctuate by more than 50 percent from year to year. The only way to know your radon level is by testing.

GUEST:

José Luis Gutiérrez Villanueva

Specialist Radon Measurement Advisor, Radanova

https://www.linkedin.com/in/joseluis-gutierrez-radonspecialist/

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Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we dive into a groundbreaking study published in The Lancet Public Health titled Impact of Ultra Low Emission Zone on Lung Function Growth in Children in London: A Prospective Parallel Cohort Study, to explore a question that fundamentally challenges how we think about air pollution and child health: What if the single biggest barrier to protecting our children's respiratory health isn't our lack of scientific knowledge or technology—but our complete failure to recognise that when we clean up urban air pollution, children's developing lungs don't just stop getting worse, they actually catch up, proving that early life deficits can be restored and that clean air zones are not just environmental policy, but direct biological interventions with immediate, measurable health benefits?

Key Topics Discussed:

• The Scale and Methodology: A Masterclass in Longitudinal Research: Known as the CHIL study, the Children's Health in London and Luton study, this was a prospective parallel cohort study. The researchers approached 122 primary schools and an impressive 69 percent agreed to participate. They recruited a massive cohort of 3,414 children aged six to nine years old. They followed these kids over four to five year periods, performing annual spirometry tests right in the school to measure FEV1, forced expiratory volume in one second, and FVC, forced vital capacity. They coupled these clinical tests with high resolution dispersion modelling to estimate annual air pollution exposure at each child's home address. This is rigorous, large scale, longitudinal public health research at its finest.
• Complete Recovery: The Gap Was Closed: Then London implemented the ULEZ and over the follow up period the researchers watched a dramatic shift occur. The children in London saw their FEV1 growth increase by an extra 10 millilitres per year compared to the children in Luton. Because of that accelerated growth, after just four years of follow up, the children in London did something many experts thought was impossible. They reached complete parity with Luton. The gap was completely closed. Even more astonishing, the proportion of children in London with clinically impaired lung function fell from 14 percent at baseline down to just 9 percent by the end of the study. The introduction of the London ULEZ was associated with improved lung function growth trajectories, suggesting that previous deficits in lung development were restored.
• The Built Environment Connection: Historically, we have often treated building ventilation and outdoor air quality as two entirely separate silos. But this paper proves that they are intimately connected. Outdoor air is the raw intake for our indoor environments. By implementing clean air zones like the ULEZ, we are performing a massive city scale pre filtration of our indoor air. If we can close a 38 millilitre lung deficit and restore clinical impairment just by cleaning up the ambient city streets, we are proving that environmental interventions have an almost immediate direct biological benefit. If cleaning up outdoor air can do this, imagine the health optimisation we can achieve if we combine ambient clean air zones with high quality filtered and mechanically ventilated indoor spaces. We spend 90 percent of our lives indoors after all.

The Air Quality Matters Podcast in Partnership with

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Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Lindab (https://www.lindab.ie/) - S&P UK (https://www.solerpalau.com/en-uk/)

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Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we sit down with Brian Renda, Programme Director for the Built Environment, and Victoria Slaughter, PPE Director at Blueprint Biosecurity, to explore a question that fundamentally challenges how we think about pandemic preparedness: What if the single biggest barrier to preventing the next pandemic isn't our lack of scientific knowledge or technology—but our complete failure to recognise that preparing for respiratory pandemics requires pathogen agnostic infrastructure deployed before emergencies strike, high quality respirators accessible to everyone who needs them, and a fundamental shift from accepting pandemics as inevitable to building systems where outbreaks are contained before they spiral into global catastrophe?

Key Topics Discussed:

• Post COVID Reality and the Challenge of Sustained Preparedness: It is incredibly hard to plan and respond to threats that are not immediately in front of you. During the pandemic, the risk was visible and destructive. Now that attention has shifted, it is difficult to maintain focus on the next pandemic when we do not know if it will happen in one year, ten years, or a hundred years. Blueprint's role is to advance our overall state of readiness so that while we may not be able to stop outbreaks from happening, we can stop them from progressing into pandemics. History has shown we cannot predict when the next large event will be. We must be in preparation mode, but we cannot assume we have infinite time. The earlier preparations are done, the better protected we are.
• The Mask Versus Respirator Problem: So much of the confusion and misinformation during COVID stemmed from a lack of access to high quality products. There is an enormous difference between a mask and a respirator. A respirator filters the air a user breathes to a regulatory standard such as N95 or FFP3. A surgical mask or cloth mask does not. Surgical masks are designed to catch large particles and spit from a wearer's mouth in sterile environments. They are not designed to filter aerosols or airborne particles. The lack of any standard for cloth masks meant protection was wildly variable. Some offered almost no protection at all. When people are given high quality respirators with known efficacy, they do not have to wonder if something is protecting them. That changes everything.
• Stockpiling Strategy and the Lessons from COVID Waste: Respirators do expire, but the standards are extraordinarily high because these products are a person's last line of defense. Most respirators last longer than their expiration date, but manufacturers want to ensure even the final 0.1 percent that may no longer be good does not reach a person. Some respirators have shelf lives upwards of 20 years. That is very different from products that expire every three years. Smart stockpiling means filling warehouses with products that are ideal for long term storage and allowing for product rotation. Post COVID, many stockpiles are starting to disappear simply because products are expiring.
• The Built Environment Programme and Pathogen Agnostic Technologies: Blueprint focuses on interventions that are pathogen agnostic, work in occupied spaces, have promising safety and efficacy profiles, integrate into current operations without major disruption, and have the potential to be cost effective. Their formal programmes include Far UVC at 222 nanometers, which has much higher exposure limits than conventional 254 nanometer UVC because of its shorter penetration depth. Conventional upper room GUV, which has been studied since the 1930s yet is still barely used. And glycol vapors such as propylene glycol and triethylene glycol, which have been shown to deactivate aerosolized pathogens and are already mass manufactured for industrial processes. These could be deployed during emergencies with emitters in homes or businesses to add air treatment capacity with relatively little cost or infrastructure.

Brian Renda https://www.linkedin.com/in/brian-renda-4264132/

Victoria Slaughter https://www.linkedin.com/in/victoriaslaughter/

Blueprint Biosecurity https://blueprintbiosecurity.org/

• The Air Quality Matters Podcast in Partnership with
  
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This week, we dive into a study published in Atmospheric Pollution Research titled Effects of Classroom Ventilation Management and User Activities on Indoor Air Quality in Madrid Primary Schools: A Two Year Field Study, to explore a question that fundamentally challenges how we think about school environments and indoor air quality: What if the single biggest barrier to delivering healthy classroom air isn't our lack of scientific knowledge or technology—but our complete failure to recognise that asking teachers to be human HVAC controllers, manually managing windows while teaching 30 active children in densely packed spaces, is a fragile, unstable and fundamentally unsustainable way to manage a building?

Key Topics Discussed:

• The Research Design: A Two Year Behavioral Intervention Study: This Madrid study wanted to see if we could solve this problem through behavioral management alone. They set up a two year field study monitoring nine classrooms across four primary schools. During the first year, they just watched. They recorded business as usual, teachers and students opening and closing windows and doors completely freely based on whether they felt hot, cold or stuffy. Then in the second year, they intervened. They implemented a structured seasonal adapted manual ventilation protocol in one classroom per school, using the other classrooms as controls. This protocol was highly detailed. It scheduled specific window and door openings, such as five minutes at the start of the classroom, during every recess and during lunch breaks. And it adapted the width of the window opening based on whether it was freezing winter, mid season or a warm spring afternoon.
  
  
• The Human Factor: When Compliance Breaks Down: The biggest weakness of all is the human factor. A manual ventilation protocol is only as good as the people executing it. Compliance was highly erratic. In the dead of winter, teachers simply refused to open the windows because the cold drafts were unbearable. During exams or quiet study periods, windows stayed closed because the outdoor street noise was too distracting. If a teacher was in the middle of a complex, engaging lesson, they forgot about the protocol entirely. We are essentially asking teachers to be human HVAC controllers, managing drafts, noise, security and air quality, all while trying to teach 30 young children. It is a fragile, unstable and unsustainable way to manage a building.
• The Carbon Dioxide Results: Alarming Spikes and Protocol Limits: During lessons with closed windows, CO2 built up at an alarming rate, frequently soaring well past 1500 parts per million and even 2000 parts per million within 30 minutes. When the scheduled breaks arrived and the windows were opened, levels dropped rapidly. Did the structured protocol help? Yes, it did. The intervention classrooms had generally lower average CO2 levels than the business as usual classrooms. But even with strict compliance, they still recorded major CO2 spikes during long, densely occupied teaching blocks. It proved that in high density classrooms, manual natural ventilation simply cannot keep up. Passive window opening has physical limits, especially when wind speeds are low

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Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we sit down with Amanda Reddy, Executive Director at the National Centre for Healthy Housing, to explore a question that fundamentally challenges how we think about housing quality and public health: What if the single biggest barrier to transforming housing quality isn't our lack of scientific knowledge or technology—but our complete failure to recognise that the places where we spend 70 percent of our lives, our homes, are either actively supporting or systematically undermining our health, and that fixing housing for the most vulnerable fixes it for everyone?

Key Topics Discussed:

• Lead Is Not a Solved Problem: Half a million children in the United States are still exposed to lead levels that threaten their ability to learn and thrive every year. Lead affects neurodevelopment, lowers IQ, impairs executive function and increases the risk of conduct disorders. But it also affects adults. A World Bank study estimated that lead exposure causes five and a half million deaths globally each year, more than AIDS, malaria and road traffic deaths combined. The amount of lead required to poison a child is invisible. Imagine a sugar packet of lead contaminated dust spread evenly over an American football field. That is still enough to be hazardous. You cannot clean your way out of this problem. You have to eliminate the source.
• The Three Pillar Strategy: The National Centre for Healthy Housing operates through research, policy advocacy and community capacity building. They identify what works through rigorous evidence, advance those solutions through federal, state and local policy changes, and then support communities to implement those solutions on the ground. But they do not arrive with predetermined answers. Communities own the bus. They decide where they are going, how fast and what route to take. The Centre brings expertise, tools and evidence to help navigate barriers, but the solutions are shaped by the people who live the experience every day.
• Climate, Housing and Health Collide: Extreme heat now affects 70 percent of Americans. Housing is central to how communities weather climate events, whether heat, cold, hurricanes or wildfires. But much of the existing housing stock was not built for the climate we are experiencing today, let alone the climate we will face in 2050. Seventy percent of the homes that will exist in 2050 are already built. Energy efficiency retrofits that sealed homes to save energy are now trapping heat. Communities are calling for a right to cooled air as part of habitability, just as heating became a requirement a century ago. But air conditioning every home is not the answer. Refuge spaces, community cooling centres, heat island mitigation and building design all have a role. The challenge is ensuring climate solutions do not fall disproportionately on low income residents who contributed least to the problem.
• Military Housing and Cultural Barriers: Over the past decade, military families have raised serious concerns about housing conditions. Mould, water damage, lead and poor maintenance are widespread. Military families face unique cultural pressures that make it difficult to report problems or advocate for repairs. Fear of repercussions for service members creates a chilling effect. Yet the cost of inaction is profound. A service member worried about their family's safety at home is a readiness issue.

GUEST:

Amanda Reddy

Executive Director, National Centre for Healthy Housing

https://nchh.org/

The Air Quality Matters Podcast in Partnership with

Mann + Hummel https://www.mann-hummel.com/en.html Particles Plus https://particlesplus.com/

Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Lindab (https://www.lindab.ie/) - S&P UK (https://www.solerpalau.com/en-uk/)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) - Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast) - Farmwood (https://farmwood.co.uk/) - iE Electronics (https://www.eielectronics.ie/) and iAir Group (https://iair-group.com/)

Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/

This week, we dive into a study published in Building and Environment titled The Impact of Energy Retrofit on Indoor Air Quality in Classrooms and Offices, to explore a question that fundamentally challenges how we think about building performance and climate action: What if the single biggest barrier to decarbonising our building stock isn't our lack of technology or ambition—but our complete failure to recognise that when we tighten buildings to save energy, we risk sealing in pollutants, moisture and carbon dioxide, turning our classrooms and offices into actively harmful environments unless we treat mechanical ventilation as an absolute physical necessity, not an optional luxury?

Buildings in Europe are responsible for about 40 percent of our total energy consumption. If we are going to meet our climate and decarbonisation goals, we have to retrofit our existing building stock. There is no way around it. But there is a massive fear in our industry, and we have seen it happen time and time again, that when we tighten up these buildings to stop heat loss, we end up destroying indoor air quality. This Irish study is important because it did a rigorous pre and post retrofit evaluation of over 50 classrooms and offices, measuring CO2, fine particulate matter, nitrogen dioxide, temperature, humidity and a whole suite of volatile organic compounds.

Key Topics Discussed:

• The One Week Snapshot Problem: The biggest methodological limitation is that the monitoring campaigns are only one week long per phase. A week is just a snapshot in time. It does not capture seasonal variations. If the pre retrofit monitoring happened during a mild windy week in autumn when the windows were open and the post retrofit monitoring happened during a freezing calm winter day with everything shut down tight, the weather and teacher behaviour would heavily skew the results. A classroom environment is highly dynamic. The number of students, the specific lessons being taught, and even the type of cleaning products being used can vary wildly from one week to the next. This is a critical limitation that must be acknowledged when interpreting the results.
• The VOC Wildcard: The study noted that while ventilation improved overall, the response of volatile organic compounds was highly variable across different buildings. Why? Because energy retrofits introduce new synthetic materials into the built environment. New insulation, new sealants, new paints and sometimes new carpets and furniture. These materials off gas chemical compounds leading to short term spikes in total VOCs, even when the overall ventilation rate is technically higher. This is a critical warning to our industry. We cannot just focus on the ventilation rate. We must also practice strict source control by selecting low emitting natural materials during retrofits where we can or perhaps increase ventilation rates in the early stages of habitation of these spaces.
• The Carbon Dioxide Victory: Carbon dioxide concentrations in the retrofitted classrooms actually reduced by an average of 28 percent. That is a massive improvement. And why did this happen? It happened because the retrofits did not just focus on insulation and air tightness. They actively integrated mechanical ventilation with heat recovery.
• The Particulate Matter Win: PM2.5 levels decreased by 27 to 30 percent in both classrooms and offices. Before the retrofits, the buildings exceeded the WHO daily average guidelines for PM2.5 on 48 percent of the monitored days. After the retrofit, that number dropped to 26 percent. This is a huge public health victory, likely driven by the high efficiency filtration systems in the new mechanical ventilation units and tighter building envelopes keeping outdoor traffic pollution from leaking in.

The Impact of Energy Retrofit on Indoor Air Quality in Classrooms and Offices

10.1016/j.buildenv.2026.114963 (https://doi.org/10.1016/j.buildenv.2026.114963)

The Air Quality Matters Podcast in Partnership with

Mann + Hummel https://www.mann-hummel.com/en.html Particles Plus https://particlesplus.com/

Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Lindab (https://www.lindab.ie/) - S&P UK (https://www.solerpalau.com/en-uk/)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) - Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast) - Farmwood (https://farmwood.co.uk/) - iE Electronics (https://www.eielectronics.ie/) and iAir Group (https://iair-group.com/)

Zehnder https://www.zehndergroup.com/en

Charity Partner - https://www.saferairproject.org/