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Dr. Alex Huffman (he/him) Profile picture
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8 Nov, 6 tweets, 5 min read
Many are fighting hard at local levels for improved indoor air quality in schools (wrt COVID & beyond). One prejudice against portable HEPA purifiers is perception of "high-cost vs minimal benefit."
via @Ecole_Oubliee

A few resources below. Do you know other/better arguments? 🧵
2/ On the cost-effectiveness of HEPA filtration & ventilation. This @JohnsHopkinsSPH report from May 2021 touches into the cost of purchase & replacement for schools (+ much more).

Report via @polsiewski @ggronvall @WBahnfleth @Ep1Chrissy @Vahey_R et al.
3/ This article by Prof. Jensen Zhang from @EngineeringSU thinks through IAQ control strategies, but includes some discussion of portable HEPA filtration cost.
tandfonline.com/doi/full/10.10…
4/ On cost-effectiveness of HEPA filtration in schools, I've often pointed to the thread below by @CorsIAQ from Feb. 2021 (& multiple other versions).
Topic also discussed in the WaPo article by @CorsIAQ & @j_g_allen from July 2020: washingtonpost.com/opinions/2020/…
5/ Switching gears to add just a little (of many studies) about effectiveness of clean air using HEPA filtration, this study by Curtius et al. from March 2021 shows strong reduction in particle concentration in school room air:
tandfonline.com/doi/full/10.10…
6/ And another on in-room HEPA use (and layered with masks), this study by Lindsley et al. showed that:
masks reduced aerosol by 72%, HEPA by 65%, together by 90%.
cdc.gov/mmwr/volumes/7…

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More from @HuffmanLabDU

Dr. Alex Huffman (he/him) Profile picture
9 Nov
"On Friday night, Colorado’s COVID-19 modeling team released a new report warning that if nothing changed, 1,393 people could be hospitalized with the virus by late Nov.
It took less than three days to exceed that projection."

Article: @MegWingerter (1/x)
denverpost.com/2021/11/09/col…
2/ Data on vaxxed (breakthrough) vs unvaxxed cases & hospitalizations in Colorado always comes up as an important question. ⬇️

So get yourself & family vaxxed. But if even so, still important to be careful right now. #MaskUpColorado

Data: covid19.colorado.gov/vaccine-breakt… ImageImage
3/ Unfortunately, it's not just one area of Colorado seeing spikes. This is somewhat anecdotal, but here are cases in one suburban Denver school district. Currently on a streak of six consecutive school days of new highs.

(dips each week on weekends when less testing) Image
Read 7 tweets
Dr. Alex Huffman (he/him) Profile picture
10 Oct
The movement to bring #CO2 sensors to school empowers parents, students, & teachers to advocate for their health; Reveals invisible factors of air quality & helps see how well ventilation is matched to room activity.

Great article by @EmilyAnthes. (1/🧵)
nytimes.com/2021/10/10/hea…
2/ If you are able to buy or borrow a CO2 sensor, stick it in the mesh water bottle pocket of your kid's backpack, pin into their shorts, or send in their lunchbox. Be creative. Make sure it isn't sealed away; the more airflow the better the reading.
3/ A key goal of #COVIDCO2 monitoring is to understand how well ventilation is matched to room activity & occupancy. Share the data with your school. If CO2 rises above 800 ppm, interventions needed to reduce build-up of aerosol & risk.
Read 19 tweets
Dr. Alex Huffman (he/him) Profile picture
9 Oct
A “wellness” clinic in Colorado Springs has been barred from giving COVID vax shots bc of improper procedures.

The clinic “typically offers medical aesthetic services, such as Botox injections, laser hair removal, acne treatment”
By @TATIANADFLOWERS
coloradosun.com/2021/10/08/dr-…
“More specifically, clinic employees did not monitor storage unit temperatures for vaccines at all times and failed to use equipment and practices that comply with guidance from the federal Centers for Disease Control and Prevention, the news release said.”
“It is unclear if the Colorado Medical Board, which regulates doctors and other licensed health providers, or any other state or federal agency will take action against Dr. Moma clinic leaders.”
Read 5 tweets
Dr. Alex Huffman (he/him) Profile picture
30 Sep
Good article by @tanyalewis314 w/ summary of why we need #BetterMasks & practical tips.

Again, consistent voices from aerosol scientists that improved masks important for Delta. Quoted here: @linseymarr @kprather88 @masknerd; & see @projectn95. (1/x)
scientificamerican.com/article/why-we…
2/ Given that N95 supply has been reported fine for months, strange the CDC article comment was that “CDC continues to recommend that N95 respirators should be prioritized for protection against COVID-19 in healthcare settings”

cdc.gov/coronavirus/20…
3/ Thread by author @tanyalewis314 about the article in @sciam on improved masks:
Why We Need to Upgrade Our Face Masks—and Where to Get Them
scientificamerican.com/article/why-we…
Read 4 tweets
Dr. Alex Huffman (he/him) Profile picture
29 Sep
Airborne transmission of SARS-CoV-2 in indoor environments: A comprehensive review

Article lives up to it's comprehensive billing. A few plots, points from the paper (1/x)

HT @WBahnfleth
Article info: tandfonline.com/doi/abs/10.108…
Full preprint: linkedin.com/feed/update/ur… Image
2/ Fascinating summary of weekly global COVID cases (left) and Google search for "COVID is airborne" (right) with some key moments highlighted. Image
3/ They summarized ASHRAE guidelines on how ventilation rate changes with occupant density for different types of spaces. Image
Read 5 tweets
Dr. Alex Huffman (he/him) Profile picture
24 Sep
Preprint: "Echoes Through Time: The Historical Origins of the Droplet Dogma & its Role in the Misidentification of Airborne Respiratory Infection Transmission"

Worth time to read through fascinating history that @jljcolorado & this group unraveled. (1/x)
papers.ssrn.com/sol3/papers.cf…
2/ So many article authors on Twitter worth following incl: @jljcolorado @linseymarr @katierandall @EThomasEwing @zeynep @trishgreenhalgh @Don_Milton @jmcrookston @DFisman @Orla_Hegarty @Marcel_Loomans @WBahnfleth @pkubioaerosol @WargockiPawel @kprather88
papers.ssrn.com/sol3/papers.cf…
3/ If you want to digest aspects of the story in deeper form, spoon-fed via Twitter thread, this is a long 🧵 that @jljcolorado put together in May along similar lines:
Read 4 tweets

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