Thread by @jljcolorado

1/ HOW TO AVOID TRANSMISSION and have #CleanAirHolidays?

Most important: understand and explain clearly that we get infected by breathing infected air (aerosols) exhaled by SOME (not all) the infected

Mainly in close proximity, and in shared room air

journalofhospitalinfection.com/article/S0195-…

2/ Recognize that this is an INDOOR PANDEMIC

20 times more likely to get infected indoors than outdoors (can only be explained by airborne transmission)

DO EVERYTHING YOU CAN OUTDOORS (family and work meetings, schools etc.)

pubmed.ncbi.nlm.nih.gov/33249484/
nytimes.com/2020/07/17/nyr…

3/ If you have to go indoors, there is NO SILVER BULLET. You need to do multiple things to reduce risk.

I.e. the "SWISS CHEESE" model of @MackayIM

#CleanAirHolidays

4/ A mnemonic to remember what to do: "A CIVIC DUTY"

time.com/5883081/covid-…

#CleanAirHolidays

5/ Try to MINIMIZE time spent INDOORS, and with as few people as feasible. Understand that distance helps, but is not enough

#CleanAirHolidays

numeroteca.org/cat/en-el-aire/

6/ Understand that PLEXIGLASS BARRIERS help in a cashier / teller situation. But they actually INCREASE TRANSMISSION when lateral, as they make ventilation more difficult.

dx.doi.org/10.1126/scienc…

7/ Understand that DISINFECTION OF SURFACES is an UTTER & COMPLETE WASTE OF TIME AND MONEY

(except perhaps in hospital COVID ward, per the @CDCgov)

nature.com/articles/d4158…
cdc.gov/mmwr/volumes/6…

#CleanAirHolidays

8/ Understand that LOUD VOCALIZATION (talking, yelling, singing) is STRONGLY associated with transmission.

Talking less loudly (or not talking when possible, e.g. public transportation) reduces transmission a lot.

arxiv.org/abs/2009.04060

#CleanAirHolidays

9/ MASKS are the most effective layer of protection indoors.

bmj.com/content/375/bm…

MASKS ARE NOT SIEVES, they can filter aerosols much smaller than the gaps in the mask through microscopic mechanisms.

medium.com/@asit.mishra76…


#CleanAirHolidays

10/ Any mask is better than no mask. But to work best, masks need to:

1) Be a good filter (aerosols stick to it when air goes through its cloth)
2) Let us breathe (low resistance)
3) NOT LEAVE GAPS between face & mask - BIGGEST PROBLEM IN THE REAL WORLD

11/ Since #COVIDisAirborne and AIRBORNE IS THE DOMINANT mode of transmission (see our paper in @TheLancet, thelancet.com/article/S0140-…), we should recommend higher quality masks, especially for riskier situations when sharing indoor air

FFP2/3, N95, or elastomeric

#CleanAirHolidays

12/ How to GET RID OF VIRUS IN INDOOR AIR?

1) Get rid of air & floating virus: ventilation - BEST
2) Keep air, remove virus: filtration - GOOD
3) Keep air + floating virus, "kill" virus: disinfection - DANGEROUS, AVOID (except UV disinfection, does work)

#CleanAirHolidays

13/ How to know that VENTILATION IS GOOD ENOUGH?

Measure CO2 with an infrared meter (NDIR, ~$100). Keep it below 700-800 ppm (parts per million)

See section 9 of Bit.ly/FAQ-A

#CleanAirHolidays

14/ Install PUBLICLY-VIEWABLE CO2 meters everywhere where we share indoor air

(Can be done for low cost $200 or so per location -- much lower than pandemic economic losses)

See section 9 of Bit.ly/FAQ-A

#CleanAirHolidays

15/ If ventilation is not sufficient or practical, then go with FILTRATION.

- Commercial HEPA filters: work well, but they are expensive, huge variation in cost, quality, and noise (many companies selling substandard ones)

#CleanAirHolidays

https://twitter.com/marwa_zaatari/status/1439101890621550596

16/ But filters DO NOT NEED TO BE HEPA!! Cheaper filters built with a regular (Comfort) fan and HVAC filters work just as well and are much cheaper. E.g. #corsirosenthalbox

#CleanAirHolidays

en.wikipedia.org/wiki/Corsi-Ros…

17/ For more information on the science, the historical errors that have made it so difficult for @WHO and @CDCgov and other govs. to accept that #COVIDisAirborne etc., see this thread and the linked articles and threads:

https://twitter.com/jljcolorado/status/1461356173081276420

#CleanAirHolidays

18/ Este mismo hilo en español / castellano:

https://twitter.com/jljcolorado/status/1463211154457575427