Alex Huffman, Ph.D. - Profile picture
(bio)aerosol scientist & professor in chemistry dept. @DUsciencemath; he/him Mastodon:
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Oct 7, 2022 4 tweets 3 min read
Important article by @PatriciaFabianS & @jonlevyBU: investment in improving school air quality is critical.

Adds to reminder by @IAQinGWN at #AAAR2022 yesterday that investing in filtration can realize $10-100 return per $ spent e.g. via ⬇️ absences.… Well-maintained HVAC filters or portable air cleaners can “also clean the air of pollen particles, mold spores & pollution from car exhaust and industrial operations. And in areas where wildfires are common, filters reduce the concentration of smoke particles inside buildings.”
Aug 18, 2022 66 tweets 44 min read
"Indoor Air Management of Airborne Pathogens: Lessons, Practices, and Innovations"…

Workshop by @theNASEM focusing on the current state of knowledge ➡️ practical lessons learned. Session 1 starting now.

Live-tweets below
#EHMI #NASEM #EnviroHealthMatters ImageImage 2/ @Don_Milton summarizes evidence that saliva PCR much better at catching COVID positive cases than PCR from nasal swabs. ImageImage
Jul 6, 2022 23 tweets 9 min read
A family emergency means I’m flying today for the first time since 2019. Fortunately I’ve got my N95 to reduce my inhaled dose as much as possible + my CO2 meter to gauge air.

Short 🧵 to occupy me while on a layover.

The CO2 was nicely & low in the Shreveport, LA airport (1/x) ImageImage 2/ On this tiny United commuter flight, 45 minute flight time from Shreveport to Houston, no one with N95 masks. Maybe 2 w/ surgical masks.

Boarding & taxi process, the #AirplaneCO2 briefly peaked at 1600 ppm, but mostly in 1100 range. Obviously higher than ideal, but not bad. Image
Apr 4, 2022 11 tweets 5 min read
Excellent OpEd by @linseymarr & @jljcolorado on the early and persistent confusion around the word "airborne" wrt the pandemic. It's a short overview on the effects of these miscomms across medical & disciplinary boundaries.
Some salient quotes, links (1/)… 2/ “This fundamental misunderstanding of the virus disastrously shaped the response during the first few months of the pandemic & continues to this day. We still see it now in the surface cleaning protocols that many have kept in place even while walking around without masks. …”
Jan 14, 2022 15 tweets 13 min read
CDC came out with another incremental update on #mask & #respirator guidance today:…

Clarifies N95s aren't in short supply & can be worn again!

It's still not perfect, but it feels like we're at least inching in the right direction. Some thoughts via a🧵. 2/ New statement that most respirators (i.e. #N95s) "are disposable and should be discarded WHEN they are dirty, damaged, or difficult to breathe through."

So you CAN #ReuseN95s‼️
See, e.g.:

That's *much* better guidance than to toss after a single use!
Jan 12, 2022 6 tweets 6 min read
Really happy to see our paper led by @DaveyRachel1 just out in the #Forefront section of @AnalBioanalChem:

Improves a procedure to expose surrogate proteins to urban air (especially NO2, O3) to quantify changes in protein nitration ➡️ allergies, etc.
1/🧵 Image 2/ @DaveyRachel1 did a great job of quantifying & improving each step of the #bioanalytical procedure; ozone loss across PM filters, extraction & detection efficiencies, even good old analytical #FiguresOfMerit sensitivity & limit of detection. Image
Jan 6, 2022 4 tweets 4 min read
If you have more experience & credibility than Dr. @brosseau_lisa on topics of industrial hygiene, aerosol science & mask use, etc. - then by all means speak up.
Otherwise, dispense w/ silliness that surgical masks are safer than N95s. Use #BetterMasks.
🔹… 2/ See also this additional flurry of tweets by @brosseau_lisa on the importance & use of high-quality N95 respirators:
Jan 5, 2022 6 tweets 4 min read
It's frustrating to see pervasive misunderstanding that N95 masks (respirators) need to be fitted or they are useless. Some of the same people champion surgical masks instead.
Illogical - If N95s don't work unless prof. fitted, how could surgical masks w/ big gaps work better? 1/ 2/ The chart & thread here gathered by @akm5376 helps add perspective. Yes, a professionally fitted N95 provides tremendous protection! But even a un-fitted N95 is better than almost anything else, b/c the filtration is great & fit is already good.
Dec 17, 2021 12 tweets 5 min read
Another good study simulating effects of masks, HEPA cleaners, ventilation in a small meeting room. By NIOSH team incl. Lindsley, et al.…

🔸 Masks reduced aerosol by 50% +
🔸 Additive further exposure reduction w/ any combo of HEPA, ventilation
Summary 🧵 2/ For reference, this is essentially the same NIOSH team that did some other really nice work on masks and air cleaners:
Dec 5, 2021 14 tweets 8 min read
Nice mask study ~consistent w/ prev. results.…

"... face masks sign. reduce the risk of SARS-CoV-2 infection compared to social distancing. We find a very low risk of inf. when everyone wears a face mask, even if it doesn’t fit perfectly on the face." 1/🧵 2/ The authors perform "upper bound" analyses to get around complexities in modeling risk.

"We conclude that wearing appropriate masks in the community provides excellent protection for others and oneself, and makes social distancing less important."…
Dec 2, 2021 10 tweets 6 min read
The #Omicron variant has been found in Colorado, thx to thorough surveillance by @CDPHE.

Omicron cases now detected in three counties in the US. I live in one of them. Seems like a great*time to take both individual & collective responsibility to slow spread. How?
Short 🧵 Image 2/ Don't freak out. It's "not a time for panic, a time for caution." You have some indiv control over your COVID health risk:
✅ Vax + boost yourself & family
✅ Wear a tight-fitting, high-quality mask
When possible:
✅ Avoid crowded areas
✅ Move meetings outside
✅ Open windows
Dec 1, 2021 10 tweets 8 min read
"Mask mandates are back for the Denver metro area. Here are the types of masks you should be wearing."
Article by @oscarcontrarius for @DenverChannel

Me: Although any mask can help some … just ditch your old one & upgrade to better fit & quality.
[1/🧵]… 2/ On the subject of #BetterMasks and new #MaskMandates, I recently gathered a bit more info & motivation in this thread:
Dec 1, 2021 7 tweets 6 min read
Led by @RommieAmaro, "a team of 50 scientists has for the first time created an atomic simulation of the coronavirus nestled in a tiny airborne drop of water."

“People have literally never seen what this looks like.”
Article by @carlzimmer @13pt:…
(1/x) 2/ The @nytimes article by @carlzimmer @13pt is a fantastic overview of the complexity of viruses hitching a ride in aerosols. Little drops full of virus, proteins, mucins, surfactants, lung fluid, water.

The simulations are mind-blowingly cool.…
Nov 30, 2021 19 tweets 13 min read
"Nearly 40% of COVID cases related to outbreaks in Colorado are at schools"; By @EricaBreunlin @fishnette

This is equally unsurprising & disappointing. I'm torn by thoughts that districts often:
* are overwhelmed
* largely ignore airborne prevention
🧵⤵️… 2/ There have been *countless* sources for good, data-backed science on how to radically slow COVID spread in schools. Pick from any number of excellent Colorado experts or widen the net to advocates & experts all over the country and world.
The solutions are ready to be applied.
Nov 29, 2021 16 tweets 10 min read
Never been a better time to help improve indoor air quality:
* Schools may see COVID increases from holiday travel
* Omicron variant threatening
* Black Fri & Cyber Mon deals at play

If you have any $ margin, consider buying a HEPA filter or two for your local school.
(Short 🧵) 2/ Many commercial HEPA air cleaners you can choose from. Choose:
✅ Enough CADR for room (~2/3 of room area)
✅ HEPA (& ignore ionization/plasma)
✅ Look for lower cost & sound

See excellent thread by @marwa_zaatari w/ helpful tips & data below:
Nov 24, 2021 14 tweets 8 min read
Several counties in Colorado put a #MaskMandate order into effect starting today:…
It's a great time to remind people that masks aren't all the same. Any mask is more effective than no mask, but better fit & filtration quality upgrades protection.
Short 🧵 2/ There are so many great articles & resources on choosing a good mask, I picked just a few examples.
This article by @yeahyeahyasmin in @TheAtlantic is a great discussion of the need to wear #BetterMasks:…
Nov 15, 2021 14 tweets 8 min read
Discussions today about our Thanksgiving got me thinking about what guidance has been put out lately. Thoughts & links in a 🧵. (1/x)

Gathering for the holiday brings risk, but some efforts can make it somewhat safer. A range of thoughts by PH experts:… 2/ @mimbsy talked with @KatherineJWu on her ideas about how to be safest for Thanksgiving.…
Nov 12, 2021 4 tweets 2 min read
I can't believe Colorado is actually having mtgs to draft possible care rationing plans before seriously working towards preventing people from being infected in the first place.

How is this the 21st century? We effing know how to slow it down, people. 1/… 2/ “I would hate to see… sending someone home who’s homeless”. Um, ya. I think that would pretty well violate medical oaths!

Draft plans being discussed in preparation for the possibility of hospital beds & staff being overwhelmed in Colorado.… Image
Nov 9, 2021 8 tweets 5 min read
"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)… 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

Nov 8, 2021 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.
Oct 10, 2021 19 tweets 13 min read
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/🧵)… 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.