Prof. Jose-Luis Jimenez@jljcolorado
Nov 23, 2021
18 tweets
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 @ɪᴀɴ ᴍ. ᴍᴀᴄᴋᴀʏ, ᴘʜᴅ 🦠🤧🧬🥼🦟
#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 @CDC)
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
youtu.be/eAdanPfQdCA
#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
youtu.be/mJ81IBTMvcU
11/ Since #COVIDisAirborne and AIRBORNE IS THE DOMINANT mode of transmission (see our paper in @The Lancet, 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
twitter.com/marwa_zaatari/
Marwa Zaatari@marwa_zaatari
Sep 18 21
View on Twitter
1a - Selection Graph - All (includes ionizers = unproven tech)
- X axis first cost + first year filter replacement cost in USD
- Y axis: Clean Air Delivery rate = volume of clean air in CFM (cubic feet per min) = ~efficiency x airflow
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 @World Health Organization (WHO) and @CDC and other govs. to accept that #COVIDisAirborne etc., see this thread and the linked articles and threads:
twitter.com/jljcolorado/st
#CleanAirHolidays
Prof. Jose-Luis Jimenez@jljcolorado
Nov 18 21
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1/ HOW COVID TRANSMISSION WORKS: the short version
I believe it is extremely important to communicate clearly how transmission really happens.
Then, one can understand easily real ways to limit transmission. And it reduces resistance to e.g. masks.
18/ Este mismo hilo en español / castellano:
twitter.com/jljcolorado/st
Prof. Jose-Luis Jimenez@jljcolorado
Nov 23 21
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1/ ¿COMO EVITAR LA TRANSMISION DE COVID ESTAS VACACIONES?
Lo + importante: entender que nos contagiamos al respirar aire infectado (aerosoles con virus) exhalado por ALGUNOS (no todos) los infectados
En proximidad cercana, y en aire compartido en habitación
#CleanAirHolidays
Prof. Jose-Luis Jimenez
@jljcolorado
Dist. Prof. Chem. & CIRES, Univ. Colorado. #HighlyCited2021, Fellow AAAR & AGU. Aerosols, pollution #EndFossilFuels #COVIDisAirborne https://t.co/XIzMmaLNh7 https://t.co/o4YmfYG18L
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