Air Quality Matters

This week, we sit down with Plum Stone, founder and CEO of the Safer Air Project, to explore a question that fundamentally challenges how we think about indoor air quality and accessibility: What if the single biggest barrier to transforming indoor air quality isn't our lack of scientific knowledge or technology—but our complete failure to recognise that millions of people living with chronic health conditions face invisible barriers to accessing public spaces every single day, and that fixing air quality for the most vulnerable fixes it for everyone

Key Topics Discussed:

The Lived Experience of Poor Air Quality: For people living with chronic health conditions, poor air quality is not an abstract future risk. It is a daily, immediate barrier to participation in public life. For someone with a compromised immune system, an underventilated classroom or meeting room can mean a week of illness, hospitalisation, or worse. For their families, it means constant vigilance, isolation, and the burden of protecting themselves when policymakers and building operators fail to act. This is not just a health issue. It is an accessibility issue. And yet, unlike wheelchair ramps or hearing loops, air quality remains invisible, unregulated, and largely ignored.

Prevention as the Biggest Lever: Whilst the Safer Air Project started by advocating for people with existing chronic health conditions, Plum has come to see air quality as the single biggest lever we have to prevent chronic disease in the first place. Cardiovascular disease, stroke, dementia, asthma, and long term respiratory conditions are all driven by exposure to poor air quality. If we can push down on air pollution and airborne infection transmission, we give ourselves a real head start on prevention. This is not just about protecting the vulnerable. It is about reducing the growing burden of chronic disease on society and freeing up resources to invest in health, not just treat illness.

Making the Invisible Visible: The first step to solving any problem is measuring it. The Safer Air Project is running a global campaign called Making the Invisible Visible, asking organisations to monitor air quality in public spaces and display that information transparently. If you are not measuring it, you are not managing it. And if you are not making it visible, people cannot make informed decisions about their safety. The campaign is simple. Monitor your air quality. Display your air quality. Commit to transparency. This is not just about CO2 numbers. It is about giving people the information they need to assess risk in real time, whether that is a vulnerable person deciding whether to enter a space, or a facilities manager realising their ventilation system is not performing as it should.

The Role of Unions and Workplace Safety: Unions have been at the forefront of workplace safety for centuries, yet they have been almost entirely absent from the air quality conversation. That is starting to change. The Australian Council of Trade Unions has been a strong advocate, recognising that air quality is a workplace health and safety issue. Employers have a responsibility to provide safe working environments. That includes the air employees breathe. The new Model Code of Practice for the Control of Biological Hazards in the Workplace recognises biological hazards that transmit through the air. This is a huge step forward. But enforcement and implementation remain the challenge. Unions have the power to demand safe air for workers. And when you fix air quality for workers, you fix it for students, patients, and the public.

GUEST:

Plum Stone

Founder and CEO, Safer Air Project

https://www.saferairproject.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 A Scalable Framework for Impact Analysis of Faults on Indoor CO2 in Buildings, to explore a question that fundamentally challenges how we think about building maintenance and indoor air quality: What if the single biggest barrier to delivering healthy indoor environments isn't our lack of technology or standards—but our complete failure to recognise that the faults we routinely ignore in HVAC systems are actively degrading the air we breathe, and we've had no systematic way to prioritise which faults actually matter until now?

Key Topics Discussed:

The Correlation Versus Causation Problem: In a building, everything is connected. If you just look at raw data, you might see counterintuitive things. For example, when the outdoor air damper is wide open, CO2 levels might actually be higher. A simple correlation analysis might conclude that opening the damper causes CO2 to rise, which makes no physical sense. What's actually happening is demand controlled ventilation. The system opens the damper because CO2 is rising. High CO2 is causing the damper to open, not the other way around. It's a classic feedback loop. To get around this simultaneity bias, the researchers used a clever approach called double machine learning. They stripped away all the noise and confounding variables like building ID, time of day, weather and current CO2 baseline, so they could isolate the true causal impact of a specific fault on CO2 levels.

The Worst Faults for Air Quality: The absolute worst fault for indoor air quality is an AHU discharge fan failure. When the fan isn't generating the static pressure needed to move air, supply airflow drops off a cliff and return air CO2 spikes. The next worst is a poorly tuned system where the outside air damper is oscillating wildly, constantly cycling back to its closed position, severely reducing the overall volume of fresh air entering the building. Then there are valve leaks. A leaking cooling valve causes the supply air temperature to drop too low. The control system opens the heating valve and closes the outside air damper to keep warm air in. Because of a leaking cooling valve, your fresh air intake gets choked off and indoor CO2 shoots up. A leaking heating valve does the opposite. It opens the outside air damper to take advantage of free cooling, which actually dilutes indoor CO2 and improves air quality, but at a massive energy penalty.

Zone Level Faults: At the zone level, the worst fault is terminal unit airflow set point unreachable low. This is when the VAV box damper is stuck or there's a ductwork issue, and the actual airflow to the room is consistently lower than what the thermostat is asking for. You get localised underventilation and zone CO2 spikes dramatically because fresh air is simply not getting into the space.

The Prioritisation Framework: In facility management, we are constantly bombarded with fault alerts. In a large building, you might have hundreds of alerts a day, and maintenance teams are almost always stretched thin. Without a way to prioritise those faults, you end up ignoring them or focusing only on the ones that trigger immediate comfort complaints. This paper provides an evidence-based, data-driven ranking that lets facilities teams prioritise maintenance actions based on their actual impact on both energy and indoor air quality.

A scalable framework for impact analysis of faults on indoor CO2 in buildings

https://doi.org/10.1016/j.buildenv.2026.114443

The Air Quality Matters Podcast

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

Do check them out in the links and on the Air Quality Matters Website. (https://www.airqualitymatters.net/podcast)

If you haven't checked out the YouTube channel its here (https://www.youtube.com/@airqualitymatters-SimonJones). Do subscribe if you can, lots more content is coming soon.

This week, we sit down with Lisa Greenfield, Regional Programme Manager for the Midwest at the Centre for Green Schools at the US Green Building Council, to explore a question that fundamentally challenges how we think about educational environments: What if the single biggest barrier to transforming school air quality isn't our lack of scientific knowledge or technology—but our complete failure to recognise that schools need practical roadmaps, peer networks, and trusted voices who've walked the path before to turn good intentions into real world action?

Coming from a family of educators and having spent almost 20 years in the classroom herself, Lisa brings a deeply personal perspective to this work. After developing allergic asthma from mold exposure in her own classroom, and later experiencing long COVID that kept her out of teaching for three months, she left the profession to make a bigger impact. Now she's building the infrastructure to help hundreds of school districts across the United States navigate the complex journey toward healthier indoor environments.

Key Topics Discussed:

The Fellowship Network: The Centre for Green Schools is launching its largest cohort yet, bringing on 53 fellows from public school districts across the country. These aren't consultants or outside experts. They're facilities managers, finance directors, operations staff, and district leaders who will learn together, implement the Energy Efficiency Indoor Air Quality Toolkit, and become mentors for the next wave. The goal is simple. Build a peer network where schools that have already navigated this journey can guide those just starting out. Because nobody wants to reinvent the wheel. They just need someone to hold their hand and show them what good looks like.

The Stakeholder Ecosystem: Improving school air quality requires buy in from decision makers like superintendents and school boards, implementers like facilities managers, the teachers and staff who work in those buildings every day, the students who spend up to 10 hours breathing that air, and the parents who can become powerful advocates. Each group sees the problem through a different lens. But when you frame it properly, fiscal savings from reduced absenteeism, lower health insurance premiums, improved test scores, better teacher retention, the case becomes compelling across every stakeholder group.

Schools as Workplaces: We often talk about children in schools, but teachers spend entire careers in these buildings. One in 13 students has asthma. But teachers are the ones who may develop COPD, allergic asthma, or long term respiratory illness from decades of exposure. Lisa's story is not uncommon. Too many educators have gotten sick from mold, poor ventilation, or chronic pathogen exposure. These are workplaces. Employers have a responsibility to provide safe environments. Yet air quality is rarely treated with the same urgency as fire safety, water quality, or food standards.

The Funding Reality: American schools face a $90 billion annual funding gap. They are the second largest infrastructure in the nation after roads and highways. Most school funding comes from local real estate taxes, which creates massive inequity. Title I schools, rural districts, and tribal schools often lack the resources for preventative maintenance, let alone major HVAC upgrades. But here's the thing. You don't need to overhaul an entire system on day one. Start with ventilation and filtration. Measure what's happening. Make small changes. Be transparent. Show progress. The roadmap exists. The toolkit is free. The support network is being built. Funding often follows when expectations are set and schools demonstrate genuine effort.

GUEST:

Lisa Greenfield

Regional Programme Manager, Centre for Green Schools, US Green Building Council

https://centerforgreenschools.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

Do check them out in the links and on the Air Quality Matters Website. (https://www.airqualitymatters.net/podcast)

If you haven't checked out the YouTube channel its here (https://www.youtube.com/@airqualitymatters-SimonJones). Do subscribe if you can, lots more content is coming soon.

This week, we sit down with David Gottfried, co-founder of the US Green Building Council and founder of the World Green Building Council, a movement now spanning 85 countries that has ignited a trillion-dollar green building economy.

What if the single biggest barrier to transforming the built environment isn't our lack of scientific knowledge or technology—but our complete failure to recognise that green building, while extraordinarily successful, is still just putting solar panels on the Titanic unless we fundamentally rewire how civilisation values life itself? Key Topics Discussed: • The Unlikely Origins of a Movement: It's easy now with hindsight to forget just how unlikely the green building effort was back then.

The idea that buildings could be designed, constructed and operated in ways that meaningfully reduced environmental impact was not a given. David walked into rooms as an early green building consultant and faced the same three developer questions every time. Will it slow my project down? Will it cost more? Will it even work?

The movement spent years fighting that perception, proving that green buildings could be more profitable, lower risk, and deliver better performance.

• From Green to Regenerative: Green building has become a multi-trillion dollar global movement. We have rating systems in 181 countries. We've saved monstrous amounts of energy. But the slope of climate change is still steep. CO2 is at 430 ppm when scientists say don't go past 350. Global population is 8.2 billion headed to 10.

A billion people still have no electricity, no fresh water. Countries are dropping bombs. AI is consuming electricity at an exponential rate. Green building is flattening the curve, but it's not reversing it. We need to move beyond sustainability, which is neutral, and embrace regeneration. If you're 500 pounds overweight and you change your diet to be neutral, you're going to be 500 pounds till you die. We need to lose weight. We need to regenerate.

• The Architecture of Love and the Codes for Life: David's new book, Regen360, synthesises decades of experience, 200 conversations with AI, 2,600 pages of transcripts, and a lifetime of reflection into 15 fundamental codes for regenerative civilisation. Each code is distilled into a simple equation. If it destroys life, then it is false. Truth equals oxygen. Love equals regeneration. Wealth equals health on planet Earth. These aren't abstract philosophies. They're operational frameworks for rewiring capitalism, governance, technology and human behaviour. The book is David's last lecture, his modern elder contribution, interwoven with personal stories, memoir, and a call to action for the next generation.

• The Role of AI and the Next Generation: David used AI, specifically ChatGPT and Claude, as thought partners to synthesise his ideas, challenge his assumptions, and structure the book. AI can be the differentiator of governance, helping us move from the hot amygdala survival wiring to the smart prefrontal cortex. But AI also consumes electricity and CO2. The tool is phenomenal, but it creates externalities. The book is written for everyone, but especially for college students, the next generation who will inherit this mess. David is teaching sustainable finance at Stanford next spring, but he'll be talking to the soul in the student. He's sorry for the world his generation is handing over, but he's here to help, with tools, maps, compasses, and Regen Circles to create base camps for the change agents climbing the mountain of Earth.

GUEST: David Gottfried https://regen360.net/

Author, Regen360: An Operating System for Regenerative Earth

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 Do check them out in the links and on the Air Quality Matters Website.

This week, we dive into a fascinating study published in Railway Engineering Science titled Study on Air Quality Improvements in Train Compartments by Coordinating Exhaust of Multiple Air Outlets, to explore a question that fundamentally challenges how we think about ventilation in mass transit: What if the single biggest barrier to protecting passengers on high speed trains isn't our lack of technology—but our complete failure to recognise that static, one size fits all ventilation systems can never deliver both thermal comfort and effective infection control across changing seasons?

Key Topics Discussed:

The Physics of Human Thermal Plumes: Most modern trains pump fresh conditioned air in from vents in the ceiling. But where does that stale air go? Usually it's exhausted through vents down near the floor. This study used CFD modelling to look at what happens if we rethink that. What if we coordinate exhaust at both the top and the bottom of the carriage? Human bodies create thermal plumes. We are basically 100-watt heaters and warm air naturally rises off us, carrying our exhaled breath upwards. In the summer, when the air conditioning is trying to cool the cabin, if you exhaust the air entirely from the top of the carriage, like near the luggage racks, you are working with that natural thermal plume. The hot, polluted air rises off the passengers and gets sucked right out of the top vents. The study found this significantly improves the cooling efficacy and efficiency. You aren't forcing hot air down past passengers to reach the floor vents. It also clears out pollutants near the passengers' breathing zones much faster.

The Winter Problem: In the winter, the scenario flips. You're trying to heat the cabin. If you pull all the air out from the top vents, you are just sucking all that nice buoyant warm air straight out of the roof before it reaches the passengers, leaving their feet freezing. It creates massive temperature stratification and makes people incredibly uncomfortable. The study found that in winter, a 50 50 split using both the top and the bottom exhaust provides the best balance. The bottom exhaust pulls the warm air down to feet level, maintaining thermal comfort, while the top exhaust still helps capture the rising respiratory pollutants.

The End of Static Ventilation Design: This proves that static one size fits all vent designs is dead. You cannot have a ventilation system that operates the exact same way in January as it does in July and expect optimal results for both comfort and importantly infection control. We need dynamic systems. If you want to truly manage the risk of airborne transmission in mass transit, while simultaneously hitting our net zero energy efficiency targets, train manufacturers and frankly designers of any large, densely occupied space, need to implement variable exhaust systems that adapt to the season, the thermal load and the occupancy.

The Future of Mass Transit Ventilation: It's a brilliant example of how nuanced, targeted and responsive our ventilation strategies need to become to protect public health in the built environment, especially technical ones like trains. You can imagine the exact same thinking being applied to buses, to aeroplanes and so on. This is the frontier of mass transit air quality management.

https://link.springer.com/article/10.1007/s40534-025-00398-0

The Air Quality Matters Podcast in Partnership with

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

Do check them out in the links and on the Air Quality Matters Website. (https://www.airqualitymatters.net/podcast)

If you haven't checked out the YouTube channel its here (https://www.youtube.com/@airqualitymatters-SimonJones). Do subscribe if you can, lots more content is coming soon.