David Elfstrom 🍁

@davidelfstrom.bsky.social

11089 Followers 1421 Following

P.Eng, Energy management, measurement & verification. Toronto, Canada. Born 327ppm CO2. Climate Action & electrification; Safer infrastructure; cycling; air filtration & ventilation

A four-panel comic by Nathan W. Pyle depicts a humorous take on a spoon sliding into a bowl. In the first panel, a smiling, anthropomorphic spoon rests on the rim of a bowl of orange soup, saying, "JUST DOIN' MY JOB READY TO SERVE!" In the second panel, a close-up shows the spoon relaxing into the liquid, noting, "HEY THIS SOUP FEELS SO NICE AND WARM..." By the third panel, the spoon slides lower, leaving only its face visible as it says, "THINK I'LL JUST SLIDE DOWN A BIT". In the final panel, the spoon is almost entirely submerged with only the top of its head peeking out, its final speech bubble cut short with "AW YE-"
Red full moon rising above a treed hill reflected in the still water of a lake. A boulder is in the foreground at the water's edge.
Child's hand touching bright green soft moss on a forest floor
Ontario's ambient air monitoring stations all very low PM 2.5 1-2 ug/m3
TAME Unit 2 at University of Toronto St George reading of 0.4 micrograms per cubic meter on July 22 2026 at 7:38 AM EDT
TAME unit 5 - Baby Point, Toronto, showing last 24 h readings
Tissue on the front of a box fan, being held on by suction
Post to /r/crboxes by gopher_xyzpdq Zine: How to build an air purifier for <$75 CR Box Build Guide I made a zine with instructions on how to build a cheap & effective air purifier (1-fan CR Box). The folder also has a presentation version of the instructions. Link Materials are just a box fan, the box the fan comes in, & MERV 13 filter held together with tape (design based on optimizations/testing by David Elfstrom). Share with anyone affected by the wildfire smoke plume or wants cleaner air!
Purple Air map of PM2.5 expressed as cigarettes per day, shown over greater Toronto area, values around 12 per day depending on location
Purple Air map of air quality in Ontario expressed as cigarettes per day
Specification sheet for Teledyne T640 featuring broadband spectroscopy white-light scattering measurement as low as 0.18 Îźm size up to 20 Îźm size.
Temtop S1 air quality monitor with 268 Οg/m3, 26.6 °C, 66.5% RH. US AQI score 318
Official ground station PM 2.5 measurement of 500 Îźg/m3 for July 15 2026 in Brantford Ontario Canada
Brantford: hourly fine particulate matter readings with a near vertical rise in PM 2.5 on July 15 2026
Air Quality Ontario for Sarnia is stable at 12 Îźg/m3 PM2.5
Financial Times: SpaceX bond yields rocket towards junk Won't someone think of the bondholders? NASA photo of astronaut pointing to a screen with a photo of Earth and the moon with a cheeky caption that he is pointing to "SpaceX 2056 spreads on a chart"
Kitchener: hourly fine particulate matter PM2.5 concentrations, Air Quality Ontario. Flat line around 20 micrograms per cubic meter until 7 am July 15 2026 when it has gone up by an additional ~40 micrograms per hour until present reading of over 300 at 1 PM
Photo of Brantford air quality measurement station, a boxy structure approximately 10x10x10 feet with metal siding, an air intake hood, and equipment on the roof
Brantford: hourly fine particulate matter PM2.5 concentrations, Air Quality Ontario. Flat line around 10-20 micrograms per cubic meter until 9 am July 15 2026 when it has gone up by an additional ~20 micrograms per hour until present reading of 220 at 2 PM
Weather Network: Toronto 25 C, Simcoe 32 C at 1:41 PM July 15 2026
MSN air quality map of southern Ontario showing high particulate matter in the Toronto area (orange/red) while in Norfolk County it's much better (green)
Air Quality Ontario page for Toronto Downtown: hourly fine particulate matter PM2.5 concentrations has a 503 Service Temporarily Unavailable message for the subframe that normally displays the current hourly plot of PM 2.5 level for the past three days
Toronto Downtown: hourly fine particulate matter PM2.5 concentrations plot for July 12-14 2026
Screen shot of TAME project surface air quality data for University of Toronto downtown campus for PM 2.5 for the week of July 8 to 14 2026.
Ontario Demand for July 14 2026 showing a potential peak at hour ending 17 (6 PM EDT) followed by a small drop one hour later
Firesmoke.ca map of forest fires, most by particulate matter intensity are clustered in NWT
Hourly Ontario Demand at 3 PM EDT: 24,897 MW Today's Projected Peak: 25,923 MW at 7 PM EDT
Email to customer relations at IESO: Please correct units on the website for the Demand Response status text: Hi IESO, Can you please drop the 's' from the units for the Demand Response status notice that appears at https://www.ieso.ca/power-data The units imply megawatt-second as currently written. Image on the right: shows the correct version on the website with the proper units.
Ontario Demand chart for July 14 shoeing the current demand at the top of the range of the band for the top 10 Ontario peaks for the current base period.
Weather Network: Another heat event is taking shape across the Greater Toronto Area, with some all-time temperature records in jeopardy
Screen shot of IESO control room b-roll video showing a graph of Embedded Renewable power.
Ontario Demand for July 14 2026 showing demand at 10 AM (11 AM eastern prevailing time) Eastern Standard Time of 22,454 MW. It's now in the green band of top ten Ontario peaks for this base period year.
In the screenshot below the text "284 MWs" has a red X marked over the letter "s", because MWs implies megawatt-seconds, just as how MWh is megawatt-hours. Demand Response Status: Scheduled Save on Energy Demand Response participants will reduce energy use between 5–8PM EDT. Projected demand has been reduced by 284 MWs to reflect the activation of the Save on Energy Demand Response programs.
Day Ahead Ontario Zonal Price for July 3, 2026. From hour 16 to hour 20 Eastern Standard Time the price was above $300/MWh, peaking at $502/MWh for hour ending 18 EST.
Ontario Zonal Price hit $100/MWh on Monday July 13 2026 while the forecast for Tuesday is $300/MW. Overnight is below $50/MWh.
Tuesday, July 14, 2026 Ontario Demand at 8:00 AM EDT 18,850 MW Market Demand at 8:00 AM EDT 20,782 MW Hourly Output by Fuel Type at 8:00 AM EDT Nuclear 10,257 MW Hydro 3,352 MW Gas 5,144 MW Wind 1,686 MW Solar 34 MW Biofuel 76 MW Storage 1 MW
Predicted Ontario Demand curve for July 14 2026 showing a peak well above the current top 10 peaks of the year with Save on Energy Demand Response indicated as Scheduled.
Child's vacation packing list, pencil on lined paper: 10. toilet trees
View along a sidewalk with bollards, and where the bollards end there is a car parked halfway on the sidewalk, which wouldn't be possible if the bollards were present
Ontario demand chart for July 1 2026 by IESO showing a green band of the top 10 peaks with 2 PM EST / 3 PM EDT being the new highest peak for the year followed by a drop of 1500 MW from 23719 MW between 6 PM and 7 PM EDT
Reddit post in /r/Oakville Monsoon Did anyone experience that wild blast of rain and wind that hit about half an hour ago? I couldn't see across the street as it rained so hard and the wind was crazy!
In New York City, where many developers appeared to be steps ahead of CDC’s updated guidance, the clean air campaign has been taken to lengths that two years ago would have been regarded as ludicrous. For example, within the boutique condominium building Charlotte of the Upper West Side, air in each residence is exchanged with fresh air 13 times a day. Entering fresh air is filtered through a state-of-the-art filtration system, which purifies the incoming air. The air passes through ultraviolet light, is adjusted for humidity and heated or cooled to temperatures the resident has set. In addition to its Swiss-engineered energy recovery ventilation system, the building includes rigorous insulation and air tight seals to limit leaks. The cumulative impact of these features will be considered as the structure seeks Passive House certification.
Blank angry goose cartoon meme
IESO Ontario Demand actual and predicted for June 11, 2026 showing the actual sliced off the top of the predicted curve.
As described
At 4 PM local time, 3 PM standard time, the Ontario demand is 1000 MW less than forecast by IESO 21,600 MW vs 22,600 MW forecast
IESO Ontario Demand hourly plot for June 11, 2026 shows a predicted maximum of 23 thousand megawatts in the early evening.
Laser imaging showing a clean air region on the outlet of the LaminAir and 4Lite, but not QT3 personal air cleaners.
View from behind of a transport truck driving right over top of a green painted bicycle lane. The bicycle lane is between two driving lanes in an industrial area.
Two cars parked next to a no parking sign in a video still
Video shows a two-lane road with sharrows in the right hand lane transitioning to a fully protected bike lane on a wider street
Hobbes: How did you do it, anyway? Calvin: I just dropped them. Hobbes: And they broke? Calvin: Well, I was tossing them to myself at the time, as I ran down the sidewalk.
Prompt: Rewrite this for LinkedIn: Just because there's a Rewrite with AI button doesn't mean you should press it. Soulless responses: M365 Copilot: Here are a few LinkedIn‑ready rewrites with different tones—pick what fits your voice: Straightforward •Just because there’s a “Rewrite with AI” button doesn’t mean you should use it. Thought‑provoking •A “Rewrite with AI” button is an option—not a requirement. Professional •The presence of a “Rewrite with AI” button doesn’t replace good judgment. Witty •Just because you can click “Rewrite with AI” doesn’t mean you should. Reflective •AI can rewrite your words—but it can’t replace your thinking. Leadership tone •AI is a tool. Knowing when not to use it is a skill. Want it punchier, more playful, or more provocative?
Unprotected green painted bicycle lane between lanes 2 and 3 on a suburban stroad where lane 3 is a highway onramp, via Google Streetview. The green paint has many black tire marks moving diagonally across it.
Avocado cut in half revealing a pit about 90 percent of the volume
Single point perspective looking down an exterior aisle. There is no one present. There are open cooling shelves on the left containing only some juice on the middle shelves and freezer doors on the right, which is an external wall. The freezer doors wrap around the corner at the back in the distance, and they are empty. The continuation of the back freezer wall is seen in the reflection on the right side doors.
If classes are outside, they are immediately walkie talkied into the building by the office staff
2022-2024 Review of The Workplace Safety and Health Act 33. Hot Water on Construction Sites The WSH Regulation requires employers to ensure a washbasin is located near each toilet in a workplace and has a supply of clean hot and cold water, soap and individual disposable clean towels or other suitable means of cleaning and drying hands. Additionally, they must ensure that the washbasin is kept clean, sanitary and operational. However, there is an exemption for construction project sites. According to the current regulation, if it is not reasonably practicable to provide washbasins at a construction project site, an employer and prime contractor must ensure that alternative adequate washing facilities are provided, such as waterless hand cleaners, hand sanitizers, clean water, soap and towels or other suitable facilities. The Review Committee recommended a new requirement that hot water for handwashing be provided at certain large construction project sites, namely industrial, commercial, and institutional buildings that are greater than 600 sq m or greater than three storeys in height, with more than 25 workers. This would ensure that workers at all large construction sites have consistent access to hot water for handwashing. The Review Committee noted that this requirement would contribute to a more consistent tendering practice for employers, as all large construction project sites would be required to comply with the same standard.