David Elfstrom 🍁
@davidelfstrom.bsky.social
P.Eng, Energy management, measurement & verification. Toronto, Canada. Born 327ppm CO2. Climate Action & electrification; Safer infrastructure; cycling; air filtration & ventilation
Reposted by David Elfstrom 🍁
This is literally the method they used for aerosol droplet sample collection.
November 11, 2025 at 12:55 AM
This is literally the method they used for aerosol droplet sample collection.
The deets in the ALT text 🥇
If Evidence Based Medicine has a poster child, it's the 2015 Antimicrobial Resistance and Infection Control study claiming N95s interfere with breathing in pregnant women.
Here's their setup, which they described as "simulating the actual wearing of an N95 respirator".
The RCT "gold standard" 🤣
Here's their setup, which they described as "simulating the actual wearing of an N95 respirator".
The RCT "gold standard" 🤣
November 11, 2025 at 12:34 AM
The deets in the ALT text 🥇
Reposted by David Elfstrom 🍁
Gas stoves emit methane, nitrogen dioxide and fine particulates at levels known to contribute to asthma and cardiovascular disease.
🧪 NEW STUDY: The annual indoor health cost of a single gas stove = $5,258
A big part this is from childhood asthma.
www.zmescience.com/medicine/gas...
🧪 NEW STUDY: The annual indoor health cost of a single gas stove = $5,258
A big part this is from childhood asthma.
www.zmescience.com/medicine/gas...
Gas Stoves Are Slowly Poisoning Homes and Cost Families Over 5,000 Dollars a Year in Hidden Health Effects
That "clean" gas stove? It's costing you a fortune in health.
www.zmescience.com
November 10, 2025 at 8:45 PM
Gas stoves emit methane, nitrogen dioxide and fine particulates at levels known to contribute to asthma and cardiovascular disease.
🧪 NEW STUDY: The annual indoor health cost of a single gas stove = $5,258
A big part this is from childhood asthma.
www.zmescience.com/medicine/gas...
🧪 NEW STUDY: The annual indoor health cost of a single gas stove = $5,258
A big part this is from childhood asthma.
www.zmescience.com/medicine/gas...
Here is the flight track for the aircraft in question. Note the ~250 knot speed because of its low altitude, about 6075 ft most of the flight, with 20 minutes at 10000 ft.
November 10, 2025 at 2:42 AM
Here is the flight track for the aircraft in question. Note the ~250 knot speed because of its low altitude, about 6075 ft most of the flight, with 20 minutes at 10000 ft.
"Great cycling cities do not use sharrows. The end."
“We never suggest using sharrows to create a bikeway,” Snyder concludes. “We’ve learned our lessons. Now that we know better, it’s time to do more.”
“We never suggest using sharrows to create a bikeway,” Snyder concludes. “We’ve learned our lessons. Now that we know better, it’s time to do more.”
Sharrows used to make sense in theory, but are now mostly useless and possibly dangerous.
momentummag.com/sharrows-use...
momentummag.com/sharrows-use...
Sharrows used to make sense in theory, but are now mostly useless and possibly dangerous
Road sharrows are about as effective as trying to protect yourself from a charging rhino with a wet paper towel
momentummag.com
November 9, 2025 at 3:26 PM
"Great cycling cities do not use sharrows. The end."
“We never suggest using sharrows to create a bikeway,” Snyder concludes. “We’ve learned our lessons. Now that we know better, it’s time to do more.”
“We never suggest using sharrows to create a bikeway,” Snyder concludes. “We’ve learned our lessons. Now that we know better, it’s time to do more.”
Reposted by David Elfstrom 🍁
@pipedreaming.bsky.social is one of the most esoterically interesting accounts I follow on here. If you are a nerd about buildings, you should follow
November 4, 2025 at 9:33 PM
@pipedreaming.bsky.social is one of the most esoterically interesting accounts I follow on here. If you are a nerd about buildings, you should follow
Reposted by David Elfstrom 🍁
Scare those viruses away - now proven by EPA! (Costume photo: Neil Comparetto)
November 1, 2023 at 2:20 AM
Scare those viruses away - now proven by EPA! (Costume photo: Neil Comparetto)
Reposted by David Elfstrom 🍁
We have ****ed the climate. Dressing this up as temporary overshoot is indefensible. But this does not mean we are doomed, & it certainly doesn't mean there is no point in trying to turn off the fossil fuel spigot. It's time to get real with climate risks.
www.technosphere.earth/derailment-w...
www.technosphere.earth/derailment-w...
Derailment warning as world faces threats to its ability to act on climate change
We may have seriously underestimated the risks of climate change. This includes derailment risks. This does not mean we are doomed, and it certainly does not mean there is no point in trying to turn o...
www.technosphere.earth
October 31, 2025 at 8:23 AM
We have ****ed the climate. Dressing this up as temporary overshoot is indefensible. But this does not mean we are doomed, & it certainly doesn't mean there is no point in trying to turn off the fossil fuel spigot. It's time to get real with climate risks.
www.technosphere.earth/derailment-w...
www.technosphere.earth/derailment-w...
Highly livable family apartment layouts that we need but unfortunately can't build in Canada or the U.S.
6 units with 16 bedrooms in a twinned point access block on ~75% of the floor plate area of this double loaded corridor w/ 9 units and 10 bedrooms. one of most compact i've ever seen
to get the same number of bedrooms in the double loaded corridor - it would have to grow by at least 2,400 sf
to get the same number of bedrooms in the double loaded corridor - it would have to grow by at least 2,400 sf
October 31, 2025 at 3:36 AM
Highly livable family apartment layouts that we need but unfortunately can't build in Canada or the U.S.
Building Science FTW! Why interzonal air flow matters in Multi-Unit Residential Buildings - presentation by Marianne Touchie of Cara Lozinsky's work. www.youtube.com/watch?v=8C-H...
Boots on the Ground: Why interzonal air flow matters in Passive House MURBS.
YouTube video by Passive Buildings Canada
www.youtube.com
October 22, 2025 at 10:28 PM
Building Science FTW! Why interzonal air flow matters in Multi-Unit Residential Buildings - presentation by Marianne Touchie of Cara Lozinsky's work. www.youtube.com/watch?v=8C-H...
When I was a child we had to separate LEGO flats from base plates using fingernails, teeth and brute force. Not all pieces survived.
What's the greatest invention of my lifetime? Computers? The Internet? Medical imaging? Incorrect. It's this:
October 18, 2025 at 1:27 PM
When I was a child we had to separate LEGO flats from base plates using fingernails, teeth and brute force. Not all pieces survived.
Happy 10th anniversary to the best political tweet, ever.
October 17, 2025 at 11:35 PM
Happy 10th anniversary to the best political tweet, ever.
21 years ago I saw the Canadian indie documentary documentary The End of Suburbia and it had a profound impact on my career.
This new article by Richard Heinberg serves an introduction and update to the issue of peak oil and what comes after.
This new article by Richard Heinberg serves an introduction and update to the issue of peak oil and what comes after.
Peak Oil for Gen Z: Seven Questions and Answers for a New Generation
Peak oil calls on us to imagine a lower-energy future and to start adapting now. It’s a game-changer, and a life-changer.
www.resilience.org
October 1, 2025 at 12:04 PM
21 years ago I saw the Canadian indie documentary documentary The End of Suburbia and it had a profound impact on my career.
This new article by Richard Heinberg serves an introduction and update to the issue of peak oil and what comes after.
This new article by Richard Heinberg serves an introduction and update to the issue of peak oil and what comes after.
New from Canadian Coalition for Green Health Care:
Displacement Ventilation: Rethinking Indoor Air for Health and Climate
Displacement Ventilation: Rethinking Indoor Air for Health and Climate
Displacement Ventilation: Rethinking Indoor Air for Health and Climate
YouTube video by Canadian Coalition for Green Health Care
youtu.be
September 26, 2025 at 12:08 AM
New from Canadian Coalition for Green Health Care:
Displacement Ventilation: Rethinking Indoor Air for Health and Climate
Displacement Ventilation: Rethinking Indoor Air for Health and Climate
The motor vehicle-centric societal thinking observed by @shawnmicallef.bsky.social is demonstrated by @ianwalker.bsky.social et al in "Motonormativity: How social norms hide a major public health hazard" doi.org/10.31234/osf... /1
September 25, 2025 at 2:55 AM
The motor vehicle-centric societal thinking observed by @shawnmicallef.bsky.social is demonstrated by @ianwalker.bsky.social et al in "Motonormativity: How social norms hide a major public health hazard" doi.org/10.31234/osf... /1
That's ... not good.
The United States will have control over TikTok’s algorithm in the acquisition of the social media platform’s US operations, White House press secretary Karoline Leavitt said.
US will complete TikTok deal ‘in coming days’ and control its algorithm, White House says | CNN Business
The United States will have control over TikTok’s algorithm in the acquisition of the social media platform’s US operations, White House press secretary Karoline Leavitt said on Saturday.
www.cnn.com
September 21, 2025 at 12:29 PM
That's ... not good.
New full-length CBC documentary on the iconic 90's music festival, Lilith Fair, on YouTube. Such great music!
Lilith Fair: The story behind the iconic ’90s music festival
YouTube video by CBC Docs
www.youtube.com
September 20, 2025 at 11:57 PM
New full-length CBC documentary on the iconic 90's music festival, Lilith Fair, on YouTube. Such great music!
Changing the filters on the open source PC fan-based air cleaner. It was still keeping the particulate mass in the bedroom below measurable (0.1 μg/m3) but it's been running for at least 17,000 hours. /1
September 20, 2025 at 11:46 PM
Changing the filters on the open source PC fan-based air cleaner. It was still keeping the particulate mass in the bedroom below measurable (0.1 μg/m3) but it's been running for at least 17,000 hours. /1
Wayfinding and footpath for the GO Train platform at Bloor Station and to/from the International Centre at Malton Station is horrible. This is my second trip this year and I still took wrong turns and wrong staircases at both stations.
September 17, 2025 at 7:41 PM
Wayfinding and footpath for the GO Train platform at Bloor Station and to/from the International Centre at Malton Station is horrible. This is my second trip this year and I still took wrong turns and wrong staircases at both stations.
Emily May Rose signs her latest piece outside Northern Contemporary gallery during the Roncesvalles Polish Festival in Toronto
September 14, 2025 at 8:08 PM
Emily May Rose signs her latest piece outside Northern Contemporary gallery during the Roncesvalles Polish Festival in Toronto
My daughter and her friends made bracelets and sold them at the street festival yesterday.
Apparently two or three people bought a pair each, and paid the higher amount!
Apparently two or three people bought a pair each, and paid the higher amount!
September 14, 2025 at 1:36 PM
My daughter and her friends made bracelets and sold them at the street festival yesterday.
Apparently two or three people bought a pair each, and paid the higher amount!
Apparently two or three people bought a pair each, and paid the higher amount!