This week, we sit down with Ben Jones, Associate Professor at the University of Nottingham and one of the lead authors of AM10, CIBSE's guide to natural ventilation in non-domestic buildings, to explore a question that fundamentally challenges how we think about ventilation strategy: What if the oldest approach to ventilation—natural airflow—still has a critical role to play in some of the most advanced buildings we're designing today, and what if we've been making the same mistakes for decades because we never really understood the fundamentals?

After a decade in development, AM10 has been completely rewritten for 2026—not just to update the maths, but to make natural ventilation accessible, understandable, and practical for everyone from salespeople to architects to engineers who need to know whether natural ventilation is even feasible for their project before they waste time and money chasing the wrong solution.

Key Topics Discussed:

• Why AM10 Needed Rewriting: The 2005 version was intimidating, dense, and assumed too much prior knowledge. The 2026 version is structured in layers—chapter two is designed so that anyone, from a student to a salesperson, can understand the basic physics. If you want the deep maths, it's there. If you just need to know whether natural ventilation will work for your building, you can get that answer quickly.

• The Physics Made Simple: Warm air rises. Pressure differences drive flow. Wind complicates everything. But somewhere on every facade, there's a neutral pressure level where the sign flips—where air stops coming in and starts going out. Controlling that point is the essence of natural ventilation design. Get it wrong, and your building doesn't breathe.

• Effective Area vs Free Area: One of the biggest changes in AM10 is how openings are measured. Combining free area with discharge coefficients into a single effective area metric forces window manufacturers to actually test their products aerodynamically and gives engineers a real number they can design with. No more fudging the geometry.

• Single-Sided Ventilation Gets Smarter: The old equations were too simplistic. The new version accounts for recirculation zones in large openings—where air comes in at the bottom, goes out at the top, and mixes in the middle. It accounts for wind-driven turbulent mixing. The result: better-sized openings that won't leave buildings overheating in summer

GUEST:

Ben Jones

Associate Professor, University of Nottingham | Lead Author, CIBSE AM10

https://www.linkedin.com/in/benjamin-jones-0686a214/

CIBSE AM10: Natural Ventilation in Non-Domestic Buildings

https://www.cibse.org/knowledge-research/knowledge-portal/am10-natural-ventilation-in-non-domestic-buildings-2026-pdf/

The Air Quality Matters Podcast in Partnership with

Particles Plus https://particlesplus.com/

Lindab (https://www.lindab.ie/) - Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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.

Chapters

• 00:00:00 Introduction: The Return of Air Quality Matters
• 00:02:14 The Genesis of AM10: A 20-Year Evolution
• 00:06:03 From PhD to Practice: Ben's Natural Ventilation Journey
• 00:08:34 The Philosophy Behind AM10: Making Physics Accessible
• 00:10:14 Why Ventilate: Sizing for Summer, Surviving Winter
• 00:11:19 The Physics of Buoyancy: When Hot Air Actually Rises
• 00:13:09 When Design Meets Reality: The Complexity Challenge
• 00:14:41 The Feasibility Question: Is Natural Ventilation Right for Your Building?
• 00:15:48 The Neutral Pressure Level: Where Physics Flips Sign
• 00:16:50 Wind's Wild Card: Adding Complexity to Buoyancy
• 00:18:44 The Case for Natural Ventilation: Energy, Carbon, and Human Connection
• 00:19:17 The Adaptive Comfort Advantage: When Control Matters More Than Precision
• 00:23:19 Natural Ventilation Through the Ages: Ancient Wisdom Meets Modern Buildings
• 00:31:59 The Outdoor Air Reality: When Fresh Air Isn't Fresh
• 00:42:15 The Great Automation Failure: 3200 PPM in London's Smartest Building
• 00:35:04 What Changed in 2026: New Physics and Effective Area
• 00:39:25 From Spreadsheets to Software: How AM10 Gets Used
• 00:40:40 Designed for Everyone: Who Should Read AM10
• 00:42:40 The Sensor Revolution: Transparency in Natural Ventilation Performance
• 00:54:26 Hot Climate Solutions: Thermal Mass and Ancient Technologies
• 00:55:47 The Fundamental Design Principle: Natural Ventilation from Day One
• 00:56:43 Getting Your Hands on AM10: Access, Training, and the Future

This week, we sit down with Danny Ashton, founder and host of HouseFresh, a consumer comparisons and testing YouTube channel and website for residential air cleaners, to explore a question that fundamentally challenges how we buy, trust, and understand indoor air quality technology: What if the air cleaner market is deliberately designed to confuse you—and what if the only way to cut through the noise is to test everything, measure what matters, and refuse to play the game?

Danny brings a rare combination of technical rigour, marketing insight, and consumer advocacy to a sector that desperately needs it. Since 2020, he has tested over 130 air cleaners in real-world conditions, measuring particulate removal performance, sound levels, energy consumption, and filter costs—creating one of the most valuable independent resources available to consumers today.

Key Topics Discussed:

• The 2020 Fog of War: What it was like looking out at the air cleaner landscape during the pandemic. A marketplace flooded with products from every corner of the planet, tested in different ways, presenting benefits in wildly inconsistent formats. An unbelievable minefield for consumers desperate to protect their families.

• The Invisible Product Problem: Why air cleaners are uniquely vulnerable to being sold poorly. You can tell if an air fryer doesn't work. You can't see particulate matter. A product could be absolutely rubbish and you'd have no idea. That opens the door for companies to sell what sells, not what works.

• The Affiliate Revenue Trap: How the entire online ecosystem is rigged around pushing products that pay the highest commissions, not the ones that perform best. Some models offer 40 to 50 percent affiliate cuts versus 2 or 3 percent for others. The incentive structure is broken, and consumers pay the price.

• What Actually Matters: Performance at quiet fan speeds, not just top speed. Energy consumption over time. Filter replacement costs. Sound quality, not just decibel ratings. The ability to turn off ionizers, UV lights, and other additive technologies. The fundamentals that marketing doesn't want you to focus on.

• The PC Fan Revolution: Why DIY air cleaners built with computer fans and standard filters consistently outperform expensive retail units on performance, noise, and cost. Clean Air Kits, New Care, Nukit—small teams delivering serious engineering without the marketing budget or the proprietary filter lock-in.

• The Carbon Filter Lie: How thin fabric carbon layers smell sweet for a few weeks and then fail completely, triggering consumers to replace entire filter assemblies. Meanwhile, thick bonded carbon filters can last significantly longer—but they cost more and don't drive repeat sales as aggressively.

GUEST:

Danny Ashton

Founder and Host, HouseFresh

Danny Ashton LinkedIn - https://www.linkedin.com/in/dannyashton/

https://housefresh.com/

https://www.youtube.com/@HouseFresh

The Air Quality Matters Podcast in Partnership with

Particles Plus https://particlesplus.com/

Lindab (https://www.lindab.ie/) - Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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.

Chapters

• 00:00:00 Introduction: The Invisible Problem with Air Purifiers
• 00:02:41 The Fog of War: Air Quality During the Pandemic
• 00:03:18 Learning from the Past: The 2010s Air Purifier Landscape
• 00:06:06 The Bamboozle Business: How Confusion Sells Products
• 00:08:07 The Testing Philosophy: Benchmarking What Actually Matters
• 00:09:37 The Sound and the Fury: Why Quiet Performance Matters Most
• 00:12:03 The Amazon Hellscape: Peak Online Shopping Meets Air Quality
• 00:13:38 The Air Fryer Test: Why Air Purifiers Are Uniquely Deceptive
• 00:29:23 The Great Filter Debate: HEPA Hype vs Real World Performance
• 00:27:12 The PC Fan Revolution: When Computer Nerds Met Air Quality
• 00:34:24 The Razor Blade Business Model: Filters as Recurring Revenue
• 00:37:26 The Size Problem: Why Bigger Really Is Better
• 00:54:30 The Sensor Gimmick or Game Changer Question
• 01:07:05 The Carbon Conundrum: When Filters Fight Odors and Lose
• 01:16:42 The Additive Air Cleaner Minefield: Ionizers, UV, and Chemistry
• 01:27:06 The Testing Reality: 133 Units and Counting
• 01:44:22 The YouTube Education Effect: Maturing the Consumer Market
• 01:37:25 The Future: Matter Protocol and Smart Home Integration
• 01:50:06 The Mission: Raising the Bar in a Rigged Market

This week, we step slightly outside the building envelope to examine a question that fundamentally challenges everything we think we know about air pollution: What if the metric the entire world uses to measure air quality is structurally blind to the most dangerous particles we breathe?

The document is a perspective piece published in the Bulletin of the World Health Organization, titled Air Quality Standards and WHO Guidance on Particulate Matter Measurement 2.5 Microns. It represents a profound wake-up call for the global air quality community, arguing that PM 2.5—the gold standard metric used worldwide to regulate, monitor, and discuss particulate air pollution—has serious fundamental blind spots that could be undermining decades of public health policy.

The World Health Organization's normative guidance on ambient air quality is fundamentally based on evidence from health and exposure studies regarding the harms associated with mass concentrations of airborne particulate matter expressed as PM 2.5. These WHO guidelines are a critical reference point for jurisdictions all over the planet when developing or revising their own ambient air quality standards. But this paper makes a stark argument: our global gold standard is missing the full scope of health-harming particulate air pollution.

Key Topics Discussed:

• The Harmonization Problem: The current WHO guidance does not cover harmonization of averaging methods for concentrations measured during data aggregation, nor does it cover how to handle exceedances of PM 2.5 levels. Variations in how different countries measure and aggregate data can obscure true ambient air pollution levels—comparing apples with oranges on a global scale.

• The Mass-Based Metric is Fundamentally Flawed: PM 2.5 is a mass-based metric. It simply weighs the dust. It completely fails to consider the physicochemical characteristics of airborne particles—their specific size, chemical composition, bioavailability of potentially harmful elements, and critically, the particle number concentrations of different sized particles, including ultrafine particles.

• The Bowling Ball vs. Marbles Problem: Imagine a box. A single bowling ball gives you a high weight reading. But what if that box is filled with tens of thousands of marbles? The mass of PM 2.5 comes mostly from larger fine particles. The mass of ultrafine particles is negligible when compared to bigger particles. However, the vast majority of particles in typical ambient environments are ultrafine particles—defined as being less than 0.1 microns. A city could hit its WHO mass targets by removing a few heavy bowling balls but leave tens of thousands of smaller marbles floating around.

• The 5 Microgram Threshold: When PM 2.5 is higher than 5 micrograms per cubic meter, the mass concentration does not correlate well with the particle number of ultrafine particles. Therefore, control measures that aim to reduce high PM 2.5 levels might not actually reduce the ultrafine particle count at all. A good correlation does exist below 5 micrograms per cubic meter, but as the authors bluntly state, most countries are far from achieving such low ambient air pollution.

• Why Ultrafine Particles Are So Dangerous: Because they are so small, they don't just get stuck in your throat or upper airways—they go deep. Short-term exposure is associated with respiratory symptoms and systemic inflammation, affecting your heart and blood pressure. Long-term exposure is associated with increased mortality, especially cardiovascular and lung-related mortality, as well as ischemic heart disease.

Air Quality Standards and WHO Guidance on Particulate Matter Measurement 2.5 Microns

Bulletin of the World Health Organization 10.2471/BLT.23.290522 (https://doi.org/10.2471/BLT.23.290522)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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

Chapters

• 00:00:00 Introduction: The Blind Spot in Our Global Air Quality Standard
• 00:01:49 The Structural Problem: Missing Harmonization in WHO Guidance
• 00:02:45 The Fundamental Flaw: Why Mass-Based Metrics Miss the Point
• 00:03:49 The Bowling Ball vs Marbles Problem: Understanding Particle Count
• 00:05:14 The Five Microgram Threshold: Where Mass and Number Diverge
• 00:06:18 The Health Threat: Why Ultrafine Particles Are So Dangerous
• 00:07:13 The Solution: Introducing PM 2.5 Number Density Metric
• 00:08:33 The Practical Challenges: Monitoring Ultrafine Particles in the Real World
• 00:09:32 The Indoor Air Quality Wake-Up Call: What Your Monitors Are Missing
• 00:11:20 The Path Forward: Harmonizing Global Standards for Real Protection

This week, we sit down with Jason Jones, Director of Air Quality Management at Fellowes, to explore a question that fundamentally challenges how we sell, specify, and sustain indoor air quality solutions in the real world: What if the biggest barrier to clean indoor air isn't technology or science—but the economic conversation we're having with the people who actually have to write the cheques?

Jason leads Fellowes' sales and marketing efforts in the air quality space, working closely with distributors, sales representatives, and end users to help them understand the role of smart, responsive air quality management. This is a theory into practice conversation, and it's critically important. We can discuss the impacts of air quality on health, wellbeing, performance, and energy all day long—but at some point, someone, somewhere, has to literally buy into the idea. Jason provides a fascinating window into how a respected player in the sector, delivering products that actually improve air quality, frames the problem and the solutions, how those conversations are going, and where they think this sector is heading next.

Key Topics Discussed:

• Post-Pandemic Reality: How air quality awareness has evolved since COVID. Some people internalized the lesson and carried it forward into the environments they work in. Others were willing to just get back to normal. The perception problem: if it doesn't smell bad, chances are the air must be clean. But we don't get to control the air we breathe in most of the spaces we're in.

• Where the Traction Is: Healthcare, education, K-12, higher ed, and assisted living facilities are where air quality is sticking most. The generation that missed prom because of the pandemic took that lesson forward into their lives. That's why there's a bright future for air quality—it made an indelible mark on that generation.

• Leaning Into Energy Savings: Why Fellowes is talking more and more about energy savings and using standards like ASHRAE's Indoor Air Quality Procedure to specify air purification alongside HVAC systems. The goal: reach the same or better air quality while reducing outside air reliance. Clean air is a human right, but the reality is that building owners have bills to pay and balance sheets to worry about.

• VRP vs IAQP—A 101: Ventilation Rate Procedure is the blunt instrument—prescriptive ventilation rates based on building type and occupancy. Indoor Air Quality Procedure is more sophisticated—designing around specific contaminants of concern, factoring in air purification and filtration, and allowing you to reduce outside air by 30, 40, 50 percent or more. Less outside air means less heating and cooling, smaller HVAC systems, and potential first cost savings.

• The Education Experiment: Schools are a massive data set. With thousands of classrooms being phased into air quality solutions over time, we'll finally be able to see clear trends in absenteeism rates, teacher sick days, and student test scores. You can't learn if you're not in class. It's that simple. And it's the most black and white metric of them all.

GUEST:

Jason Jones https://www.linkedin.com/in/jason-jones-0aa672b/

Director of Air Quality Management, Fellowes

Fellowes https://www.fellowes.com/

The Air Quality Matters Podcast in Partnership with

Particles Plus https://particlesplus.com/

Farmwood (https://farmwood.co.uk/) - Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Ultra Protect (https://www.ultra-protect.co.uk/air-quality-matters)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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.

Chapters

• 00:00:00 Introduction: The Commercial Reality of Indoor Air Quality
• 00:03:11 Post-Pandemic Reality: Who Still Cares About Air Quality?
• 00:08:09 The Budget Battle: Nice to Have vs Need to Have
• 00:10:05 The Energy Efficiency Angle: A New Way to Sell Clean Air
• 00:26:00 VRP vs IAQP: Two Approaches to Building Ventilation
• 00:24:47 The HVAC Energy Equation: Why Outside Air Is So Expensive
• 00:34:18 The Complexity Challenge: Is the Industry Ready for IAQP?
• 00:37:51 The Subjective Element: Why Human Perception Still Matters
• 01:25:09 The Fellows Ecosystem: Networked Air Quality Management
• 01:16:44 Education as the Testing Ground: The Data Goldmine
• 01:41:28 The AI Revolution: Natural Language Control of Building Systems

This week, we examine a document that represents a profound shift in how we think about school environments: What if the debate over airborne transmission and clean air in schools is finally over—and the real fight is just beginning?

The document is titled Ventilation and Air Quality in Education and Childcare Settings, published on 24 February 2026 by the UK Department for Education. It applies specifically to England, and it codifies into official government guidance something we've been arguing about for years: that good ventilation is absolutely essential for healthy and productive learning environments. This isn't a theoretical discussion anymore. This is operational policy.

The guidance plainly states that effective ventilation does more than just prevent overheating. It improves pupils' alertness and concentration. It removes polluted air. And crucially, it removes air that might contain virus particles, reducing the spread of respiratory infections like colds, flu, and COVID-19. This is massive. It places the management of indoor air quality squarely in the realm of basic school health and safety.

Key Topics Discussed:

• The Monitoring Framework: Schools are expected to regularly monitor CO2 concentrations across their buildings. The guidance provides best practices on sensor placement—at head height or table height, at least half a meter away from people, and away from doors, windows, or ventilation outlets. If you're under 800 ppm, your ventilation is good. Between 800 and 1500 ppm, it's adequate but could be improved. Over 1500 ppm, your ventilation is officially poor and you need to act.

• Pragmatic Winter Compromises: The guidance addresses the real-world conflict between keeping kids warm and keeping their air clean. Partially open windows, open higher-level windows to reduce drafts, air out rooms for 10 minutes every hour during breaks. But crucially, do not prop fire doors open to get cross ventilation.

• Beyond CO2: The document talks about multifunctional environmental sensors that can track temperature, humidity, particulate matter like PM2.5 and PM10, and volatile organic compounds from sources like formaldehyde, cleaning chemicals, body odors, and vaping products. Yes, they specifically mention monitoring for vapes.

• Air Cleaning Units—With Massive Caveats: The Department for Education is crystal clear that while air cleaning units reduce airborne contaminants including viruses, bacteria, and fungal spores, they do absolutely nothing to improve ventilation or lower CO2 levels. They are not a substitute for ventilation. The government only recommends HEPA filtration units—subtractive technology that physically catches pollutants. They explicitly reject air ionizers, ozone generators, and units with unenclosed UV fields.

• The Funding Sting: Between 2021 and 2023, the Department for Education provided CO2 monitors and air cleaning units to all state-funded education settings. But now, in 2026, the guidance explicitly states that the government will not replace faulty or damaged devices, and they will not pay for replacement filters. The ongoing financial burden of maintaining clean air has been shifted entirely onto individual school budgets.

• The Controversial Bits: The guidance talks about bringing in fresh outdoor air—a phrase doing a lot of heavy lifting when many schools are backed up against busy roads. It standardizes on NDIR CO2 sensors, which are solid but arguably already behind the times compared to photoacoustic sensors. And that 1500 ppm threshold—many in our community will argue that allowing CO2 levels anywhere near 1500 ppm is simply not acceptable for vulnerable populations.

Ventilation and Air Quality in Education and Childcare Settings UK Department for Education, 24 February 2026

https://www.gov.uk/government/publications/ventilation-and-air-quality-in-education-and-childcare-settings/ventilation-and-air-quality-in-education-and-childcare-settings

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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

Chapters

• 00:00:00 Introduction: The UK's New School Air Quality Guidance
• 00:01:15 The Science Is Settled: Air Quality as Basic Health and Safety
• 00:02:16 The Monitoring Solution: CO2 as Your Ventilation Indicator
• 00:03:19 The Traffic Light System: Understanding CO2 Thresholds
• 00:04:03 Winter Pragmatism: Balancing Warmth and Fresh Air
• 00:04:46 Beyond CO2: Multifunctional Environmental Sensors
• 00:05:36 Air Cleaning Units: The Promise and the Limitations
• 00:06:39 HEPA Only: The Government's Firm Stance on Technology
• 00:07:41 The Sting in the Tail: Who Pays for Ongoing Maintenance
• 00:08:56 The Uncomfortable Details: Fresh Air, NDIR, and 1500 PPM
• 00:10:41 The Bottom Line: Science Won, Now the Funding Battle Begins

This week, we sit down with Stephanie Taylor, a unique physician architect whose career is dedicated to bridging the deep chasm between the medical profession and the built environment, to explore a question that fundamentally challenges how we think about buildings: What if the real problem isn't just that our buildings are failing us—but that we're measuring the wrong things entirely?

As medical advisor for ThinkLite Air, she applies her clinical insights to the development of advanced air sensing and cleaning technology, transforming raw environmental data into actionable health impact scores. By integrating medical science into engineering standards, she continues to champion the idea that engineers are in many ways the physicians of the future, responsible for the preventative care of billions of people who spend so much of their time indoors.

Key Topics Discussed:

• Buildings as Extensions of Health: Why treating buildings as part of caring for human health could be one of the biggest advances of our century. The opportunities are clear: decreased acute and chronic diseases, improved productivity, better financial outcomes. But will we actually do it? The obstacles include resistance to change, difficulty bringing the medical community into building management, and the legal ramifications of talking about health.

• Defining the Finish Line: What does good indoor environmental health actually look like? Stephanie's answer: an indoor space that does not increase our physiological stress level. Not just measuring hazards, but diminishing components of the indoor environment that cause stress on our cardiovascular, respiratory, neurological, and immune systems.

• The Imperceptible Forces Problem: We design buildings and respond to environments as we can perceive them—rain, cold, visible mould. But the imperceptible exposures are the ones causing us problems. Low humidity impairing immunity. Ultrafine particles penetrating deep into the lungs. VOCs we cannot smell. The challenge is monitoring and controlling what we cannot sense.

• The Platinum Building Paradox: Why even the most advanced buildings with all the badges can fail spectacularly. A healthy buildings conference held in a room where 100 experts sat in a fog of their own breath for four hours, CO2 climbing to 3,000 parts per million in one of the smartest buildings in London. The disconnect between design intent and operational reality.

• Beyond Wells Riley: Rethinking how we model risk. The traditional Wells Riley equation models exposure to infectious bioaerosols. Stephanie is expanding that framework to model not only exposure risk, but also what indoor air quality is doing to your immune system—your protective mechanisms. It's not just how many weapons are shooting at you, but your ability to defend yourself.

• ThinkLite and the Health Index: Seeing what's going on through sensors, analyzing the data in a way that is relevant for the human body system by system—lungs, brain, cardiovascular health—and then remediating. Turning arbitrary data points into relevant health metrics. Moving from zigzag lines on dashboards to actionable health impact scores

GUEST:

Stephanie Taylor

Physician Architect | ASHRAE Fellow | Medical Advisor, ThinkLite Air

Stephanie Taylor - LinkedIn https://www.linkedin.com/in/stephanie-taylor-md-b6456b8/

https://www.thinkliteair.com/

The Air Quality Matters Podcast in Partnership with

Particles Plus https://particlesplus.com/

Farmwood (https://farmwood.co.uk/) - Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Ultra Protect (https://www.ultra-protect.co.uk/air-quality-matters)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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.

Chapters

• 00:00:00 Introduction: Buildings as an Extension of Human Health
• 00:06:42 The Medical-Building Disconnect: Why Healthcare Must Join the Conversation
• 00:12:17 Defining the Finish Line: What Does a Healthy Building Actually Look Like?
• 00:23:29 The Imperceptible Hazards: Why We Design for What We Can Sense
• 00:27:38 The Autonomic Building: Automation as an Extension of Human Physiology
• 00:33:27 The Platinum Building Paradox: When Award-Winning Spaces Fail Their Occupants
• 01:01:43 The Legal Minefield: Why Talking About Health Is Terrifying for Building Professionals
• 00:51:23 Think Light Air: Translating Environmental Data into Human Health Impact Scores
• 01:40:37 Beyond Wells-Riley: Modeling Vulnerability, Not Just Exposure
• 01:28:54 The Path Forward: Regulation, Education, and the Courage to Do the Hard Thing

This week, we tackle a question that cuts through decades of technical progress and scientific consensus: What if the reason we still don't have clean indoor air isn't because we lack the technology—but because we lack the policy to actually implement it?

The paper is a policy commentary titled Federal and State Policy Opportunities to Improve Indoor Air Quality, published in the Journal of Health Security. It's authored by a powerhouse group of experts, including Georgia Lagoudas and colleagues from Brown University, Harvard, and several other leading institutions. Many of them have been previous guests on this podcast. This isn't a theoretical exercise. It's a roadmap—a practical, actionable menu of policy interventions that could finally bring indoor air quality into the same regulatory and public health framework that we've successfully built for drinking water, fire safety, and smoking bans.

Here's the glaring truth: we spend about 90% of our time indoors, yet we have no unified national initiative for clean indoor air. We have the Clean Air Act. We have the EPA regulating outdoor air. But outdoor regulations completely fail to account for the fact that outdoor pollutants make their way inside—where we spend all our time—and they ignore the fact that indoor spaces have their own unique pollutant sources. Concentrations of certain pollutants can be two to five times higher indoors than outdoors. And outdoor regulations do absolutely nothing to address one of the biggest indoor threats: the spread of respiratory pathogens like COVID-19 and influenza.

Key Topics Discussed:

• The Current Mess: The federal government doesn't really regulate indoor air outside of occupational settings, leaving jurisdiction to state and local governments. Building codes are adopted and enforced locally, creating a massive patchwork of different standards. Some states like California, Connecticut, and Minnesota have taken steps, especially for schools, but there's no comprehensive national roadmap.

• Develop Health-Based Indoor Air Quality Targets: Right now, building owners and facility managers don't have a simple unified goal. We need clear thresholds for easy-to-measure indicators like carbon dioxide and PM2.5. The EPA or a coalition of NGOs should publish voluntary health-based targets, providing a clear benchmark that states and local entities can adopt. If you don't know what the target is, you can't hit it.

• Support States and Local Communities to Adopt Standards: Develop a national model indoor air quality code—similar to national model energy codes. Provide tax incentives to commercial buildings that make indoor air quality improvements, similar to deductions for energy efficient buildings. Create a state playbook filled with template language for regulations and building codes to make it easy for local governments to take action.

• Implement Sector-Specific Standards: Schools need indoor air quality monitors, regular HVAC inspections, and better filtration. Nursing homes should have indoor air quality standards as a strict condition of participation, just like hospitals. Federal buildings housing around a million federal employees need robust ventilation verification programs. OSHA needs to update its permissible exposure limits—many were developed in the 1970s, nearly half a century ago.

• The Two Biggest Priorities: Developing health-based indoor air quality targets and getting states to adopt indoor air quality building standards. If we can agree on what good air looks like and put it into the building code, the market will innovate to meet those demands.

Federal and State Policy Opportunities to Improve Indoor Air Quality

10.1177/23265094251410880 (https://doi.org/10.1177/23265094251410880)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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

Chapters

• 00:00:00 Introduction: The Missing Framework for Clean Indoor Air
• 00:01:12 The Glaring Gap: Why Indoor Air Quality Has Been Ignored
• 00:01:45 Why Outdoor Regulations Fail Indoors
• 00:02:22 The Astronomical Cost of Inaction
• 00:03:01 The Current Mess: A Patchwork of Standards
• 00:03:55 Recommendation One: Health-Based Indoor Air Quality Targets
• 00:04:43 Recommendation Two: Supporting States with Standards and Financing
• 00:05:38 Recommendation Three: Sector-Specific Standards
• 00:07:13 Recommendation Four: Research and the Wild West of Air Purifiers
• 00:08:30 The Bottom Line: Clean Air Is a Choice We Must Make

This week, we sit down with Frank Kelly, Professor at Imperial College London and Director of the Environmental Research Group, to examine a question that fundamentally challenges how we think about air pollution: What if the real danger isn't just how much dust we're breathing, but what that dust is made of and what it does to our bodies at a cellular level?

For over three decades, Frank Kelly has been one of the architects of London's modern understanding of air quality. His pioneering work on the oxidative potential of particulate matter has transformed how we evaluate the toxicity of everything from diesel exhaust to wood smoke. By proving how these pollutants trigger harmful free radical reactions and deplete antioxidants in the lungs, he provided the scientific backbone for London's most ambitious public health interventions, including the Congestion Charging Zone and Ultra Low Emissions Zone.

Key Topics Discussed:

• Beyond Size and Mass: Why PM10, PM2.5, and ultrafine particles are categorized by size, but size alone doesn't tell us what's actually harmful. The real story is in the chemistry, the physics, and the biology of what those particles carry and what they do when they reach the lung.

• The Meteor Analogy: Particulate matter isn't just carbon spheres. It's a complex, ever-changing cocktail of metals, gases, chemicals, and biological material that picks up and sheds components as it moves through the environment and into our bodies.

• Oxidative Potential: What free radicals are, why transition metals on particle surfaces drive oxidative stress, and how the body's antioxidant defences like glutathione, vitamin C, and vitamin E fight back. When the balance tips, inflammation and cellular damage begin.

• The Seesaw Model: On one side, you have particulate pollution with oxidative potential. On the other, your body's natural defences. Your genetics, your diet, and your environment all determine where you sit on that seesaw and when the damage starts.

• The London Success Story: How Frank's research directly influenced the introduction of the Ultra Low Emissions Zone. The data showed that children living in East London exposed to heavy traffic pollution had slower lung growth than children outside London. That evidence became the catalyst for policy change.

• Indoor Air Quality and the Well Home Study: Over 100 homes in West London instrumented for two months each to understand indoor pollution sources. The findings: damp and mould in social housing, gas cooking as a major pollutant source, and pollution migrating from kitchens into children's bedrooms where it stayed trapped overnight.

• The Microplastics Problem: Modern tyres are 55% plastic. As the fossil fuel industry loses its market in surface transport, it's shifting to plastic production. Frank's team has developed methods to characterize plastic particles in air, water, and food. The challenge: distinguishing plastic signatures from human tissue in toxicology studies.

• The Future of Air Quality Monitoring: Moving beyond mass-based metrics to real-time oxidative potential monitoring. Frank's team is developing prototype instruments that measure free radical activity in the air instantaneously, allowing us to identify which pollution sources are truly harmful.

GUEST:

Frank Kelly

Professor, Imperial College London | Director, Environmental Research Group

https://www.imperial.ac.uk/people/frank.kelly

The Air Quality Matters Podcast in Partnership with

Particles Plus https://particlesplus.com/

Farmwood (https://farmwood.co.uk/) - Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Ultra Protect (https://www.ultra-protect.co.uk/air-quality-matters)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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.

Chapters

• 00:00:00 Introduction: The Hidden Complexity of Particulate Matter
• 00:05:50 Understanding PM10, PM2.5, and Ultrafine Particles
• 00:08:01 The Lung as an Open Door: Why We're Vulnerable
• 00:09:52 The Meteor Effect: What Particles Are Really Made Of
• 00:20:41 The Seesaw Battle: Oxidative Potential and Free Radicals
• 00:25:46 The London Laboratory: Evidence That Drove the Ultra Low Emission Zone
• 00:59:13 The Indoor Air Quality Challenge: A New Frontier
• 01:11:43 The Kitchen Problem: Why Cooking Dominates Indoor Pollution
• 01:26:46 The Research Ecosystem: Eight Teams Tackling Air Quality
• 01:44:51 The Future: Real-Time Oxidative Potential Monitoring

This week, we dive into a question that challenges one of the most common assumptions in building energy efficiency: What if the chemical tests we use to validate air cleaning technology are completely missing the point—and what if the human nose is actually the most reliable instrument we have?

The paper is titled A Method for Testing the Gas Phase Air Cleaners Using Sensory Assessment of Air Quality, published in the Journal of Building and Environment. It's authored by Cantor Amada, Lee Fang, Pavel Wargocki, and colleagues from Waseda University in Japan and the Technical University of Denmark. This research was conducted as part of the IEA Energy and Buildings and Communities Annex 78 project, and it proposes a radically practical testing protocol for gas phase air cleaners—one that puts human perception at the center, not just chemical spreadsheets.

But here's the problem. Current standards typically test these air cleaners by challenging them with a few selected chemicals—measuring how well they remove formaldehyde, for example. But indoor air contains hundreds of different gaseous pollutants. If you only use chemical analysis on a handful of compounds, you might completely underestimate real-world performance. Worse, you might completely miss harmful byproducts the air cleaner is actually creating.

Key Topics Discussed:

• Subtractive vs. Additive Air Cleaners: Subtractive cleaners remove chemicals using things like activated carbon. Additive cleaners decompose chemicals using active components like photocatalytic oxidation, ion generators, UV, or ozone. Some additive technologies can transform relatively harmless pollutants into dangerous unwanted species—or pump ozone into the space. If your chemical test isn't looking for those specific byproducts, the machine gets a pass grade while actively making the room worse.

• The Two-Phase Testing Protocol: Phase one is a screening phase—do no harm. The goal is simply to make sure the air cleaner doesn't have a negative effect on air quality. Phase two is the deep dive, testing the air cleaners at various ventilation rates from very low to standard levels, with panelists rating acceptability and odor intensity.

• The UVO Zone Device Failed Immediately: One additive air cleaner—a UVO zone device—actually increased the odor intensity in the room, particularly when humans were present. It was dropped from the study. An ion generator was allowed through to phase two just to see if poor results would be repeated. They were. It significantly decreased the acceptability of the air.

• Activated Carbon Worked—But Only for Building Materials: When the pollution source was purely building materials like old carpets and linoleum, the activated carbon air cleaners significantly improved air quality. But when the pollutant source was humans—people just sitting there breathing and existing—the air cleaners did not significantly improve perceived air quality.

• The Chemical Data Lied: Parallel chemical measurements showed that total VOCs dropped significantly when using the carbon air cleaners, regardless of whether the pollutant came from materials or humans. If you were only looking at the chemical spreadsheet, you would say the air cleaners worked perfectly in all scenarios. But the human panelists were telling a completely different story. The chemical measurements simply did not match the sensory evaluations.

• The ISO 16000-44 Standard: This research heavily supports the new ISO 16000-44 standard approved in 2023, which outlines the test method for measuring perceived indoor air quality to test the performance of gas phase cleaners. The sector is slowly recognizing that the human experience is a metric.

A Method for Testing the Gas Phase Air Cleaners Using Sensory Assessment of Air Quality

https://doi.org/10.1016/j.buildenv.2024.111630

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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

Chapters

• 00:00:00 Introduction: The Challenge of Testing Gas Phase Air Cleaners
• 00:01:14 The Energy Dilemma: Why Air Cleaners Matter for Buildings
• 00:02:12 The Chemical Testing Problem: What Current Standards Miss
• 00:02:53 Additive vs Subtractive: Understanding Air Cleaner Technologies
• 00:03:43 The Human Nose Solution: Sensory Assessment as a Testing Method
• 00:04:04 The Experimental Setup: Real Materials and Real People
• 00:04:50 Phase One Results: The Do No Harm Screening
• 00:05:54 Phase Two Deep Dive: Testing at Various Ventilation Rates
• 00:06:31 The Big Reveal: When Chemical Data Doesn't Match Human Experience
• 00:07:28 The Massive Implication: Why Chemical Analysis Alone Fails
• 00:08:21 The Path Forward: ISO 16000-44 and Sensory Testing Standards
• 00:09:24 Closing Thoughts: The Human Nose Remains Essential

This week, we sit down with Mark Lynn, Managing Director of Eden Renewable Innovations and Chair of the Alliance for Sustainable Building Products, to explore a question that cuts to the heart of indoor air quality: What if the materials we bring into our buildings are the forgotten foundation of healthy indoor air—and what if natural materials offer solutions we've systematically overlooked for decades?

Recorded live at the Alliance for Sustainable Building Products Annual Healthy Buildings Conference in London, this conversation takes us deep into the world of building materials, their chemistry, their moisture behavior, and their profound impact on the air we breathe indoors. Mark brings over two decades of experience in natural fiber insulation and nearly 30 years in natural building materials, with a particular focus on building physics and the chemistry of materials.

Key Topics Discussed:

• The Forgotten Inflection Point: In the mid to late 1990s, society cared deeply about indoor air quality. MDF was scrutinized for formaldehyde emissions. Smoking bans were introduced. Ventilation moved up the agenda. But somewhere around the early 2000s, we shifted our focus entirely to ventilation as the sole solution—and stopped asking hard questions about the materials themselves.

• The Chemical Experiment: A single 1970s living room contained perhaps a dozen materials, most locally sourced. Today's living rooms contain thousands of materials, sourced globally, with complex chemistries we barely understand. We are living in a grand chemical experiment, and the results won't be clear for decades.

• Hurdle Technology and the Swiss Cheese Model: Ventilation alone is not enough. Good indoor air quality requires multiple layers of defense—elimination of harmful materials at source, moisture buffering through hygroscopic materials like wood and wool, and only then, ventilation as a final backstop. Relying on ventilation alone assumes it works perfectly. It rarely does.

• The Moisture Problem: Ventilation removes 95% of moisture from a building. But the remaining 5% can cause catastrophic problems—mold, structural decay, and poor air quality. Natural materials like sheep's wool and wood fiber can buffer moisture safely, acting as a critical redundancy when ventilation underperforms.

• Wool and Formaldehyde: Sheep's wool uniquely reacts with formaldehyde through a condensation reaction, permanently binding the carbon from formaldehyde into the keratin protein structure of the fiber. It's not just inert—it's actively neutralizing a harmful indoor pollutant.

GUEST:

Mark Lynn

Managing Director, Eden Renewable Innovations | Chair, Alliance for Sustainable Building Products

https://asbp.org.uk/

https://thermafleece.com/

The Air Quality Matters Podcast in Partnership with

Particles Plus https://particlesplus.com/

Farmwood (https://farmwood.co.uk/) - Eurovent (https://www.eurovent.eu/) - Aico (https://www.aico.co.uk/) - Ultra Protect (https://www.ultra-protect.co.uk/air-quality-matters)

The One Take Podcast in Partnership with

SafeTraces (https://www.safetraces.com/) and Inbiot (https://www.inbiot.es/?utm_campaign=simon&utm_source=airqualitymatters&utm_medium=podcast)

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.

Chapters

• 00:00:00 Introduction: The Forgotten Fundamentals of Building Materials
• 00:02:19 The Inflection Points: When We Cared About Indoor Air Quality
• 00:05:16 The Chemical Soup: Living Rooms Then and Now
• 00:08:16 The Grand Chemical Experiment: Unknown Long-Term Impacts
• 00:10:58 Custodianship and Consumption: The Lost Art of Make Do and Mend
• 00:13:07 Particles as Trojan Horses: The Chemistry Happening in Your Home
• 00:15:22 Hurdle Technology: The Swiss Cheese Approach to Risk Management
• 00:17:34 Learning from Food: Why Digestive Biscuits Have Better Moisture Science
• 00:20:15 The Ventilation Fallacy: What Happens When Your Backup Plan Fails
• 00:25:00 Natural Technology: The Evolution Already Solved the Problem
• 00:32:59 The Standards Dilemma: Innovation Versus Established Frameworks
• 00:36:00 Post-Completion Reality: When Sensors Reveal the Truth
• 00:38:27 Transparency and AI: The Coming Revolution in Material Selection
• 00:57:59 Sheep's Wool and Formaldehyde: When Materials Fight Pollutants
• 01:01:20 The Trajectory Forward: Capacity, Policy, and Bottom-Up Change
• 01:04:39 From Belfast to Buildings: Optimism Through Experience