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Chris Iddon

@chrisiddon.bsky.social
124 followers 291 following 338 posts

Music, walking, ventilation. Research fellow Chair of the CIBSE natural ventilation group

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Chris Iddon @chrisiddon.bsky.social · 28/07/2026
Results of a cluster RCT on HEPA filters in care homes tldr; finds no effect on winter respiratory infections respiratory infection rate per bedroom resident ❌ Staff absenteeism ❌ the additional CADR is pretty meagre a 🧵 1/n
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Chris Iddon @chrisiddon.bsky.social · 24/07/2026
New preprint on randomized crossover trial of HEPA air cleaners on school classroom attendance tldr; no statistical significant impact on absenteeism or symptom scoring deeper dive, read on... 1/n
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Chris Iddon @chrisiddon.bsky.social · 24/07/2026
barely visit here these days, too much to keep track across platforms, might post some interesting studies...
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Chris Iddon @chrisiddon.bsky.social · 23/01/2026
New study looking at influenza transmission 1 infected person shared small low humidity and poorly ventilated room with 8 uninfected subjects (plus 2 observers). Chatting, playing uno, bit of exercise 5000+ppm CO2 no one got infected 🧵 1/n
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Chris Iddon @chrisiddon.bsky.social · 23/01/2026
New study looking at influenza transmission 1 infected person shared small low humidity and poorly ventilated room with 8 uninfected subjects (plus 2 observers). Chatting, playing uno, bit of exercise 5000+ppm CO2 no one got infected 🧵 1/n
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Chris Iddon @chrisiddon.bsky.social · 13/01/2026
New thesis on HEPA air cleaners in school classrooms: 🧵 TL;DR: In this school study, HEPA air cleaners showed little reliable impact on absenteeism, and air-quality improvements were limited during actual classroom use.
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Chris Iddon @chrisiddon.bsky.social · 07/01/2026
New study protocol for a pragmatic, cluster-randomised, parallel, two-arm, group sequential superiority trial of HEPA filters in school classrooms to commence later this year in Norway pmc.ncbi.nlm.nih.gov/articles/PMC... -Using school absence as outcome -be interesting to see the results
pmc.ncbi.nlm.nih.gov
Classroom air purifiers for reducing school absence: study protocol for a pragmatic, cluster-randomised, parallel, two-arm, group sequential superiority trial
Respiratory infections like influenza and SARS-CoV-2 pose significant global health risks due to their high transmissibility and severity. SARS-CoV-2 has caused over 7 million deaths worldwide, and the Lancet Commission estimates a >20% chance of a ...
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Health Nerd @gidmk.bsky.social · 26/11/2025
The stuff you find when you actually read the RCTs in a systematic review... This paper is one of the foundational studies on vitamin D to prevent respiratory infections in kids. Cited 1,400 times as per Google Scholar.
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Chris Iddon @chrisiddon.bsky.social · 21/11/2025
New study on HEPA air cleaners in Finnish school study. Kids fill in daily diary of respiratory symptoms and the prevalence of symptoms reduced when the air cleaner was on. However the prevalence also decreased when the air cleaner was on but HEPA removed 🧵
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Chris Iddon @chrisiddon.bsky.social · 06/11/2025
During the COVID-19 pandemic in 2021, researchers monitored air quality in marquees and semi-outdoor venues at UK mass gatherings to understand ventilation and airborne infection risk — work that directly informed how such events could safely reopen. 🧵
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Chris Iddon @chrisiddon.bsky.social · 15/10/2025
A lot of the analysis on this misses the mark: • “They weren’t on” — maybe, but filtration data says otherwise • “Too small / not ASHRAE 241” — data disagrees. And none of it actually says anything about transmission of respiratory illnesses. 🧵1/n
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Chris Iddon @chrisiddon.bsky.social · 15/10/2025
A lot of the analysis on this misses the mark: • “They weren’t on” — maybe, but filtration data says otherwise • “Too small / not ASHRAE 241” — data disagrees. And none of it actually says anything about transmission of respiratory illnesses. 🧵1/n
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Chris Iddon @chrisiddon.bsky.social · 01/09/2025
With UK heatwaves intensifying, are passive cooling strategies enough? At CIBSE’s seminar, experts explored natural ventilation limits, AirCon efficiency, façade carbon trade-offs & why overheating in schools is a learning crisis. cibsejournal.com/technical/pu...
cibsejournal.com
Pushing the cooling limit: CIBSE Natural Ventilation Group - CIBSE Journal
The limits of passive cooling, healthy learning environments and mitigating overheating were the core subjects of a topical summer event hosted by the CIBSE Natural Ventilation Group in July. Chair Ch...
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Chris Iddon @chrisiddon.bsky.social · 01/09/2025
With UK heatwaves intensifying, are passive cooling strategies enough? At CIBSE’s seminar, experts explored natural ventilation limits, AirCon efficiency, façade carbon trade-offs & why overheating in schools is a learning crisis. cibsejournal.com/technical/pu...
cibsejournal.com
Pushing the cooling limit: CIBSE Natural Ventilation Group - CIBSE Journal
The limits of passive cooling, healthy learning environments and mitigating overheating were the core subjects of a topical summer event hosted by the CIBSE Natural Ventilation Group in July. Chair Ch...
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Chris Iddon @chrisiddon.bsky.social · 14/07/2025
ASHRAE Standard 241 sets guidelines for how much “clean air” (via ventilation, filtration, etc.) is needed in buildings to reduce the airborne spread of infectious diseases like COVID-19. But how were these numbers chosen? 1/n
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Chris Iddon @chrisiddon.bsky.social · 25/06/2025
New oped from @benjonesieq.bsky.social & me 💨 The push for better school ventilation is well-meaning, but claims that it boosts cognition or learning lack strong, causal evidence. Many studies are low quality, poorly controlled, and often overstate effects. #IAQ #ventilation #education 1/5
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rehva.bsky.social @rehva.bsky.social · 24/06/2025
The June issue of the #REHVA #Journal is out now! 📯 "#Education #Buildings: a Net Zero Transition Conducive to #Health and #Cognitive Performance". 📱 Read it online: www.rehva.eu/rehva-journa... 📨 Want to receive the #REHVA Journal in your inbox? Subscribe here: www.rehva.eu/newsletter-s...
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Chris Iddon @chrisiddon.bsky.social · 25/06/2025
New oped from @benjonesieq.bsky.social & me 💨 The push for better school ventilation is well-meaning, but claims that it boosts cognition or learning lack strong, causal evidence. Many studies are low quality, poorly controlled, and often overstate effects. #IAQ #ventilation #education 1/5
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Chris Iddon @chrisiddon.bsky.social · 06/06/2025
Just read one of the most ridiculous claims in a scientific journal discussion I've ever seen 👀 a therapeutic approach to gut microbiome to improve lung health impacts from air pollution 🤯 in rural Uganda! read on if you want to see how..1/n
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Chris Iddon @chrisiddon.bsky.social · 05/06/2025
New paper describes an in vitro method to infect cell culture with different flu strains by direct inoculation and by aerolised viral solution. Whilst it is an interesting novel methodology, I think it is limited in what it can tell us about the nature of aerosol transmission 1/n
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Chris Iddon @chrisiddon.bsky.social · 18/05/2025
The pandemic was a time when you would have thought people might want to improve their ventilation. But, behaviour change is hard because there are many barriers to change.
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Chris Iddon @chrisiddon.bsky.social · 16/05/2025
Great new study by on behavioural aspects of ventilation in hospitality venues. Many monitored venues had poor ventilation, but hosts list many barriers to improve - tho some venues attempt to improve following info campaign. let's see why it's not always simple to ⬆️ ventilation:
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Chris Iddon @chrisiddon.bsky.social · 16/05/2025
Great new study by on behavioural aspects of ventilation in hospitality venues. Many monitored venues had poor ventilation, but hosts list many barriers to improve - tho some venues attempt to improve following info campaign. let's see why it's not always simple to ⬆️ ventilation:
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Chris Iddon @chrisiddon.bsky.social · 13/05/2025
or a new study shows that either, or a combination of: ▪️reduced viral emission (bcos air cleaner added several days later from initial readings) ▪️changes to window ventilation ▪️presence of an air cleaner see below for fag packet calc to show it can't all be due to air cleaner...
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Chris Iddon @chrisiddon.bsky.social · 13/05/2025
or a new study shows that either, or a combination of: ▪️reduced viral emission (bcos air cleaner added several days later from initial readings) ▪️changes to window ventilation ▪️presence of an air cleaner see below for fag packet calc to show it can't all be due to air cleaner...
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Chris Iddon @chrisiddon.bsky.social · 07/05/2025
Off to see Bjork's cornucopia experience today. Trips to see her at the cinema are always an experience. Be that the harrowing Dancer in the Dark or the strangely hypnotic Matthew Barney art film Drawing Restraint 9. I'm sure there will be something to remember
media.tenor.com
a woman in a green fur coat is standing in front of a blue background
ALT: a woman in a green fur coat is standing in front of a blue background
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Chris Iddon @chrisiddon.bsky.social · 02/05/2025
This really interesting paper on SARS-CoV-2 viral emission dynamics in a hamster model has just been published. There’s lots to unpack, but thought I’d start on this expt that investigates characteristics of close range emission 1/n
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Chris Iddon @chrisiddon.bsky.social · 02/05/2025
Had a great time watching Stranger Things: The First Shadow. Fantastic special effects and illusions brought a gripping story to life.
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Chris Iddon @chrisiddon.bsky.social · 30/04/2025
Nice headline, scant on details. it's just a report based on a presentation given by a researcher. Look forward to seeing the methods and data. Researchers report that unknown if reduced exposure to pollution or pathogens or both is causative factor in reported absence reduction
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Chris Iddon @chrisiddon.bsky.social · 29/04/2025
Anyone know why the DHHS in the US have pulled the funding for this clinical trials for far UV to reduce indoor transmission of respiratory infections? nationalacademies.org/our-work/cli...
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Chris Iddon @chrisiddon.bsky.social · 28/04/2025
Disappointing that this headline suggests there may be causal links, when the article itself highlights the data is low quality wrt drawing any conclusions about UPF consumption and mortality bbc.co.uk/news/article...
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Chris Iddon @chrisiddon.bsky.social · 24/04/2025
Really interesting data showing how actual energy use is much lower than predicted energy use from residential EPC modelling. The gap may not be all down to how the housing is used by occupants but other assumptions that the model makes #cibsetechnicalsymposium
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Chris Iddon @chrisiddon.bsky.social · 24/04/2025
Looking forward to the CIBSE and IBPSA technical symposium today. I'll be at Session 7 Embodied Carbon and Energy Trade-offs: Optimising Building Systems
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Prof. Michael Fuhrer @michaelsfuhrer.bsky.social · 17/04/2025
Gather 'round Bluesky, while I tell the hoary tale of epidemic vs. endemic. How can it be that pandemic interventions that were vitally important in 2020 are marginally effective in 2025? Science will give us the answers! Follow me... 1/
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Chris Iddon @chrisiddon.bsky.social · 17/04/2025
Enjoyed the citrus grove at Ventnor botanical gardens yesterday and we came across what we thought was some kind of diseased lemon. Turns out its a Buddha's Hand
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Chris Iddon @chrisiddon.bsky.social · 13/04/2025
yes, you definitely need to imagine...
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Chris Iddon @chrisiddon.bsky.social · 12/04/2025
Except the data doesn't support the conclusion. The air purifier is sized at 0.44 eACH based on 34m3 card and there is no measurement of ventilation/window usage despite this being the primary removal mechanism in the space. Viral emission rates also unlikely to be constant several days in a row
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Chris Iddon @chrisiddon.bsky.social · 12/04/2025
I've been doing this wrong, instead of highlighting flaws and uncertainties in the study I should have said, increased ventilation and reduced CO2 improves your cognitive ability.
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Chris Iddon @chrisiddon.bsky.social · 11/04/2025
Watching Harry Potter with the kids and I'm like my dad used to be when I was a kid watching Dad's Army. "He's dead now, and she is, oh he's dead too"
media.tenor.com
a man with long hair and a beard says `` you 're a wizard , harry '' .
ALT: a man with long hair and a beard says `` you 're a wizard , harry '' .
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Chris Iddon @chrisiddon.bsky.social · 10/04/2025
New study shows that there *might* be some limited affect of room CO2 on doing some online cognitive test game on a phone for students after they have finished class, but sample size is small. 🧵 1/n
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Chris Iddon @chrisiddon.bsky.social · 07/04/2025
Some cool natural ventilation aspects at the natural history museum. Check out this spider underfloor air vent and the cross ventilation made the vault lovely and fresh.
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Chris Iddon @chrisiddon.bsky.social · 06/04/2025
Interesting study that purports to show transmission of SARS-CoV-2 from humans to hamsters via the air. Transmission confirmed by immune responses from hamsters. However they are unable to isolate any viral genomic material from hamsters by rt-pcr so some uncertainty 🧵
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Chris Iddon @chrisiddon.bsky.social · 06/04/2025
Went to see the stage performance of My Neighbour Totoro yesterday. Wondered how they could possibly stage iconic scenes like this, but they did! Incredible set design and a wonderful family outing. Well worth seeing if you like Studio Ghibli
media.tenor.com
a cartoon of a bear saying yawn good morning !!!
ALT: a cartoon of a bear saying yawn good morning !!!
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Chris Iddon @chrisiddon.bsky.social · 29/03/2025
Spectacular gig last night from public service broadcasting @psbhq.bsky.social. Amazing visuals brought the music to life. Incredible performance, loops, pedals, horn section, vocoders creating a cacophonous background to the spoken word recorded footage
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Chris Iddon @chrisiddon.bsky.social · 17/03/2025
A fascinating correspondence from Dr Mildred Wells (pioneer of airborne transmission with her husband). She outlines that UV irradiating classrooms will be fore-doomed to failure in preventing the transmission of airborne infections bcos of other places of transmission 1947 1/n
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Chris Iddon @chrisiddon.bsky.social · 17/03/2025
A fascinating correspondence from Dr Mildred Wells (pioneer of airborne transmission with her husband). She outlines that UV irradiating classrooms will be fore-doomed to failure in preventing the transmission of airborne infections bcos of other places of transmission 1947 1/n
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Chris Iddon @chrisiddon.bsky.social · 12/03/2025
many comments I've seen on this article are outraged with sugary drinks and suggest banning slushies. Yet it seems the tax on sugar content that has resulted in glycerol being used as a sugar substitute ingredient which has resulted in children being hospitilised www.bbc.com/news/article...
bbc.com
Children should avoid drinking slushies with glycerol, says study
Paediatricians studied 21 children in the UK and Ireland who became very ill after the icy drinks.
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Matt Green @mattgreencomedy.com · 11/03/2025
Inside the PR campaign for private schools!
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Chris Iddon @chrisiddon.bsky.social · 10/03/2025
Saw a frog whilst out on a bike ride with the kids yesterday. We got excited when we saw a couple more. A few metres further on and we could no longer keep count of how many we saw!
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Chris Iddon @chrisiddon.bsky.social · 07/03/2025
New conference poster: No evidence for portable HEPA filtration units reducing respiratory infection episodes in care home residents • No evidence that episodes of fever/ delirium, gastrointestinal infections, falls or antibiotics consumed are reduced either
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