Prof. Jose-Luis Jimenez Profile picture
Mar 24, 2022 13 tweets 7 min read Read on X
1/ El Gobierno de EEUU (La Casa Blanca, @WHOSTP45) por fin admite claramente que la COVID-19 se transmite sobretodo por aerosoles, por el aire ("airborne" = transmision aerea)

#COVIDisAirborne #SonLosAerosoles

whitehouse.gov/ostp/news-upda…
2/ "La forma más común de transmisión de COVID-19 es por pequeñas partículas que flotan en al aire [=aerosoles] minutos o horas después de que una persona infectada las haya exhalado"

"Hay varias estrategias para evitar respirarlas [..] y es importante limpiar el aire interior" Image
3/ La Administración Biden-Harris ha identificado la calidad del aire interior como una herramienta importante para luchas contra la transmisión de enfermedades de transmisión aérea en el Plan Nacional de COVID-19 (whitehouse.gov/covidplan/)" Image
4/ ¿Cómo podemos limpiar el aire de virus?

Hay 3 maneras, ilustradas aqui por @numeroteca;

(a) Echar aire y virus afuera: ventilación
(b) Quedarse con aire, quitar virus: filtración
(c) Quedarse con aire y virus, "matar" virus: desinfección

Recomendamos a y b. c SOLO con UV Image
5/ Si no hacemos nada, se acumula el virus en el aire, asi como el CO2 (que nos sirve de indicador):

Peligroso Image
6/ Con VENTILACIÓN, e.g. abrir las ventanas o con sistemas mecánicos, el aire con virus sale afuera (donde el virus se diluye muchísimo y sol lo desactiva).

El CO2 sale a la vez, y nos sirve de indicador fácil de medir. Por eso lo recomendamos para *todos* los sitios Image
7/ Con FILTRACION, el aire sigue dentro y lo seguimos respirando. Pero el virus se queda en el filtro, de donde ya no sale, y donde "muere" rápido.

[El filtro no quita CO2 (en negro), menos útil en este caso]

Filtros HEPA o **mejor y 8 veces + barato**: #CorsiRosenthalBox Image
8/ La FILTRACIÓN no solo ayuda para los virus y otros patógenos, sino que también elimina alergenos y contaminación de partículas (que son aerosoles de otros tipos). Tiene muchos beneficios aunque no haya pandemia. Image
9/ La DESINFECCIÓN con ultravioleta funciona para eliminar al virus **si se diseña, instala, y mantiene de forma profesional." Si no, puede tener riesgos serios.

Pero es mucho mas cara que los filtros portatiles. Tiene sentido en hospitales, prisiones... no en casas o escuelas. Image
10/ La DESINFECCION con métodos químicos en la mayoría de los casos no esta probada, y puede ser peligrosa. Los científicos recomendamos evitarla mientras no hay estudios revisados por pares sobre productos.

Iones, plasmas, fotocatálisis, hidroxilos, ácido hipocloroso, ozono...
11/ En este hilo expliqué esto de los limpiadores de aire en más detalle:

12/ Esto tiene que estar regulado y verificado por los gobiernos. Porque como usuarios, es difícil saber si un sitio interior es seguro o no:

[Salvo llevar tu medidor de CO2, que es muy útil] Image
13/ La Casa Blanca hace un evento de presentación sobre la ciencia de transmisión por el aire y el nuevo plan el martes 29 de marzo (supongo q habrá traducción simultánea a espanol)

Con @linseymarr @zeynep @j_g_allen and others

Para registrarse:

pitc.zoomgov.com/webinar/regist… Image

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More from @jljcolorado

May 8
1/ "After four years of fighting about it, @WHO has finally proclaimed that viruses, including the SARS-CoV-2 virus that causes COVID, can be spread through the air"



By @maggiemfoxscientificamerican.com/article/a-figh…
2/ "It took four years to get here because some leaders in public health, medicine and science clung too tightly to precision and semantics"

"One particular moment of shame came on March 28, 2020, when WHO tweeted: “FACT: #COVID19 is NOT airborne.”

3/ "Words matter. When people heard that COVID might spread on surfaces, they wasted time wiping down groceries. People who misunderstood airborne spread needlessly wore masks on outdoor walks and veered off sidewalks to avoid their neighbors."
Read 7 tweets
Apr 18
1/ @WHO has published a report on updated terminology for disease transmission

I've seen some debate about it. My take:

- Terminology itself is ok. Big progress
- But no recommendations of how to protect!

Report:

Press release: who.int/publications/m…
who.int/news/item/18-0…
2/ The report was likely the result of intense pressure on @WHO during the pandemic:

- They denied that #COVIDIsAirborne on March 2020
- They finally accepted it 2 years later

nature.com/articles/d4158…
@WHO 3/ To their credit, @WHO did invite some of their critics to be part of the committee.

What was the terminology before. In medical circles:

- droplet transmission: if it happened in close proximity, or if particles were > 5 microns

- airborne transmission: if it happened far
Read 34 tweets
Mar 28
1/ New paper in @ScienceMagazine: "Mandating Indoor Air Quality for Public Buildings"

Explaining current status of indoor air quality standards (in short: bad or non-existent), the huge health benefits that would arise from them & proposing a path forward
science.org/doi/10.1126/sc…
Image
2/ "People living in urban & industrialized societies, which are expanding globally, spend more than 90% of time indoors, breathing indoor air (IA)."

"Most countries do NOT have legislated indoor air quality (IAQ) performance standards for public spaces"

science.org/doi/10.1126/sc…
3/ "Few building codes address operation, maintenance, and retrofitting, and most do NOT focus on airborne disease transmission."

"We propose that Indoor Air Quality (IAQ) standards be mandatory for public spaces"

science.org/doi/10.1126/sc…
Read 14 tweets
Oct 4, 2023
1/ Checking the ventilation by measuring CO2 as I travel to the #AAAR2023 conference

@RideRTD bus to Denver airport. Bus route had started 3 min before I got in, already 1500 ppm

Typical of these @RideRTD buses, poor ventilation Image
2/ Not getting any better as time passes in the @rideRTD bus to the airport...

7% of the air is being re-breathed, it has already been in someone else lungs when each of us breathe it. Image
@RideRTD 3/ Given the often poor-to-mediocre ventilation in US transportation systems, I wear N95 masks (not KN95, less good)

In this case @3M VFlex, which I tested at 99.99% filtration for myself

It also stays sealed when I talk, doesn't distort my speech (& add to my Spanish accent) Image
Read 14 tweets
Oct 2, 2023
1/ Video de mi presentación sobre "Transmisión de enfermedades por el aire: cómo funciona, por qué se malentendió, y cómo reducirla"

como parte de la presentación del libro de ventilación de @aireamos

2/ Las diapositivas se pueden bajar de este enlace.

(Son de una charla más larga así que tienen más detalles, pero están todas las de la presentación de @Aireamos)

drive.google.com/file/d/1Bs0RRG…
@aireamos 3/ Miguel Ángel Campano @MA_Campano y @Aireamos han sido los motores del libro de ventilación:

Read 4 tweets
Sep 1, 2023
1/ Measuring CO2 indoors in a 10 day trip from US to Europe & back

Bus @RideRTD to Denver airport, poorly ventilated as usual.

We have not left town yet! In previous trips it kept increasing, we'll see this time. Image
2/ For background on what CO2 indoors indicates and more details, see

TLDR:
- We exhale 40000 ppm CO2
- Outdoors: 420
- Each 400 extra ppm indoors = 1% extra rebreathed air
- CO2 makes us dumber, indicator of virus & pollutants. Does not capture filteringdocs.google.com/document/d/e/2…
3/ Or by reducing recirculation. Some recirculation is ok if well-filtered, saves energy.

Energy-recovery ventilators allow ventilating well with limited energy use.

Read 18 tweets

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