Thread by @HuffmanLabDU

ICYMI, @By_CJewett did an excellent job last week on #ScienceFriday w/ @iraflatow. Worth a 14-min listen on key points about air cleaners for school & elsewhere.

Here are some additional thoughts & links on in-room air cleaners as a 🧵 (1/x)
soundcloud.com/scifri/are-hig…

2/ I think this bit from @By_CJewett takes it home:
"Your HEPA filter is kind of like a pair of kaki pants or a garden hose. It's not on-patent, it's not expensive, it's not that hard to find, and there's not a salesforce for it."
soundcloud.com/scifri/are-hig…

3/ "But what you do see is the more electronic air cleaners. Those are the companies going to the school boards, talking about ionization ... they sound spectacular"

4/ (via @By_CJewett & also @LaurenWeberHP)
"... people can make $600+ per device on some of these electronic air cleaners."
"This sounds amazing. The school board just wants to tell the parents everything is safe & things just sort of snowball from there."
soundcloud.com/scifri/are-hig…

5/ An associated thread by @By_CJewett on the radio show, with other great links to follow.
Summary of IAQ advice -- stick to HEPA filtration for in-room use and avoid ionization and other unproven technologies.

https://twitter.com/By_CJewett/status/1433900894379130880

6/ These are four of the great articles on air cleaners by @By_CJewett & @LaurenWeberHP via @KHNews:
khn.org/news/article/b…
khn.org/news/article/a…
khn.org/news/article/r…
khn.org/news/article/f…
khn.org/news/article/g…

7/ @msjpauly has also written several great articles on avoiding ionizers technology for air cleaners, e.g. here via @MotherJones:
motherjones.com/coronavirus-up…
motherjones.com/politics/2021/…

8/ Unfortunately, a LOT of schools in the US & worldwide have bought into the hype of ionization and other unproven air cleaning technology:

https://twitter.com/marwa_zaatari/status/1372358128252166144

9/ But indoor air quality experts are consistent in their strong recommendations to focus on proven technologies like HEPA filtration, ventilation, and/or upper-room germicidal UV when necessary.
E.g. letter here by @marwa_zaatari & @MarcelHarmon1:
medium.com/open-letter-to…

10/ There is a lot of evidence to support extreme caution to applying ionization for air cleaning, e.g.:
pubs.acs.org/doi/10.1021/ac…
sciencedirect.com/science/articl…
onlinelibrary.wiley.com/doi/epdf/10.11…
researchgate.net/publication/30…
epa.gov/covid19-resear…

https://twitter.com/HuffmanLabDU/status/1432830297813385222

11/ There is also plenty of reason to avoid chemical-based air cleaning technologies. For example, see this nice thread by @CorsIAQ on the dangers of ozone (O3) use indoors:

https://twitter.com/CorsIAQ/status/1434418322976612356?s=20

12/ The near-unanimous recommendation from #IAQ scientists is to apply proven technologies like HEPA filtration.

See, e.g. recommendations in this Lancet report on infectious disease resilience for school buildings. But benefits go well beyond pandemics:

https://twitter.com/HuffmanLabDU/status/1386892817402720257

13/ Or see similar recommendations by the @JohnsHopkinsSPH team, incl. @polsiewski. Same story: avoid unproven technologies, rely on ventilation and HEPA filtration indoors.

https://twitter.com/JohnsHopkinsSPH/status/1430156203754233857?s=20

14/ The studies supporting the use of proven technologies, especially in-room HEPA filtration, are seemingly endless. One important one is the Lindsley et al. study via @CDCMMWR from earlier this year:

https://twitter.com/HuffmanLabDU/status/1410998986064863235

15/ There are questions people often ask on what filtration-based air cleaner to buy. @marwa_zaatari has put out some nice analyses, like those shown below. She is a great person to follow for these.

https://twitter.com/marwa_zaatari/status/1429629474878988288?s=20

16/ DIY air cleaners like the #CorsiRosenthalBox or single-filter #BoxFaFilter units can be good choices to save some money. See e.g. this great summary resource by @CleanAirCrewOrg:
cleanaircrew.org/boxfanfilterfa…

17/ There has been a lot written recently about school districts making poor choices on air cleaners for classrooms, e.g.:
gothamist.com/news/nyc-offic…
ny.chalkbeat.org/2021/8/18/2263…
philadelphia.chalkbeat.org/2021/7/21/2258…

https://twitter.com/stephensbrent/status/1423673302535614464

18/ Again, upper-room germicidal UV is another strategy for in-room disinfection.

Webinar:

@ShellyMBoulder is an expert to follow here:
shellym80304.files.wordpress.com/2020/05/isiaq-…

19/ Much has been written on the importance of improved indoor air quality, including the needed focus on proven methods like ventilation with outdoor air & HEPA filtration. E.g. see old OpEd by @ChemDelphine, @marinavance, and me:

https://twitter.com/HuffmanLabDU/status/1385619444567666688

20/ And in the current context of Delta-COVID concerns, it's not just masks and ventilation that are important, but another opportunity to deploy HEPA filtration for immediate improvements in indoor air quality:

https://twitter.com/HuffmanLabDU/status/1428388707141263360

21/ I wanted to share some of these stories. But follow experts like these wrt topics of indoor air cleaning, e.g.
@ChemDelphine @ShellyMBoulder @CorsIAQ @stephensbrent @EarthMechanic @WaringIAQ @gcmorr @marwa_zaatari @marinavance @WBahnfleth @Poppendieck @CathNoakes @j_g_allen