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Joseph Allen Profile picture
@j_g_allen
Oct 25, 2022 • 7 tweets • 4 min read • Read on X
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SCHOOLS: I'm presenting today for a State DPH on steps schools can take on ventilation. Re-sharing some things I hope people find helpful (all available since summer 2020)

Simple #HealthyBuilding strategies: more ventilation, better filtration, portable air cleaners, VERIFY
🧵 Image
But, as I've been saying since March 2020, you can't just say 'more outdoor air' without giving a specific target. My recs is 4-6 ACH. Image
How can I determine if my classroom is meeting these targets? We have a simple 5-step guide for how to do this. Image
If you're using CO2 to determine ventilation, the 'how to' is covered in the 5-step guide. You can also use our cool little tool to help set a target CO2 level based on your ACH target. (works for offices and any other place, too! link to tool: forhealth.org/tools/co2-calc… Image
If you're using portable air cleaners, but not sure how to size them for the room, we have a tool for that, too. (rule of thumb: look for CADR of 300 for every 500 square feet) Image
The multiple benefits beyond covid and infectious disease are well-documented for every age group, and go well-beyond air quality (blow up the pic and read that table (!)

Full report here: schools.forhealth.org Image
All tools and resources can be found on the Harvard #HealthyBuildings program website: ForHealth.org.

forhealth.org

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More from @j_g_allen

Joseph Allen Profile picture
Sep 8
In @AMJPublicHealth I make an argument that adding in an economic lens is good public health practice, and I leverage an excellent article by @celinegounder and @Craig_A_Spencer.
🧵 Image
In the 1980s and 1990s, the then-new field of IAQ generated research documenting that ventilation rates above this minimum standard were associated with many health benefits.
Throughout the 1990s to 2000s, research efforts were also underway to evaluate—and expand—the understanding and value proposition of better indoor air quality.
Read 12 tweets
Joseph Allen Profile picture
Sep 7
The triple-digit temps in the southwest are catching headlines ("Record-breaking heat wave expected to extend stay in the West"). Dangerous heat, for sure, but, if you look at wet-bulb, you'll see that the headlines should be about the heat wave in the West **AND** Florida🧵 Image
How we talk about hot weather is seriously flawed. As heat waves become more intense and more frequent because of climate change, we need to change the way we think about outdoor temperatures.
We’re looking at the wrong measurement. What matters is not how hot the air is but how hot the weather is to a human body. For that, we need “wet-bulb globe temperature.”
Read 10 tweets
Joseph Allen Profile picture
Sep 6
In my Editorial for @AMJPublicHealth on the history of ventilation, I share a story not many people know...

--> In late 2020, the ASHRAE Epidemic Task Force convened a group of experts and gave them an explicit task of making recommendations on ventilation rate targets...
🧵 Image
This team submitted their first recommendations to the ASHRAE Epidemic Task Force in 2021...

...but the recommendations were never released to the public.
In the fall of 2022, the Lancet COVID-19 Commission released a report which revealed to the public the previously unreleased recommendations made by ASHRAE’s internal committee. Image
Read 9 tweets
Joseph Allen Profile picture
Sep 4
The history of ventilation is fraught, indeed. And it hasn't been told through a public health lens. I was invited to write an Editorial for @AMJPublicHealth. My reflections on how we got here, and what needs to happen next.
🧵 Image
We are in the sick building era, ushered in by a historic mistake in the 1970s with the promulgation of a standard that lowered ventilation rates in nearly every building we spend our time, and which represented a gross departure from earlier health-focused higher ventilation targets.
The year 2020 marked a major turning point in the history of ventilation. SARS-CoV-2, spread predominantly indoors, found an ally in buildings designed to minimal “acceptable” ventilation standards.
Read 4 tweets
Joseph Allen Profile picture
Aug 24
This is bad public health. "Everyone stay indoors after 6pm for the next six weeks" (also happens to be the absolute nicest time of year in Massachusetts...) Totally unrealistic, totally unnecessary, and also will just be ignored, anyway.
(A major contributing problem in Massachusetts is that we have **351** local boards of health...)
Read 4 tweets
Joseph Allen Profile picture
Jul 19
NEW from our Harvard Healthy Buildings team

We used CFD modeling to evaluate the effectiveness of portable air cleaners to help remove airborne pathogens and mitigate disease transmission in schools

[tl/dr: portable air cleaners work]

THREAD Image
Portable air cleaners work!

We found that portable air cleaners w a clean air flow rate of 2.6 h−1 reduce mean aerosol intake of all students by up to 66% Image
Air mixing matters!

**A key benefit of using PACs is to facilitate
air mixing and movement in indoor environments with inadequate ventilation** Image
Read 6 tweets

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