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jljcolorado's profile
Prof. Jose-Luis Jimenez
Prof. Jose-Luis Jimenez
Prof. Jose-Luis Jimenez
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@jljcolorado

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Prof. Jose-Luis JimenezVerified account

@jljcolorado

Dist. Prof. Chem. & CIRES, Univ. Colorado. #HighlyCited2021, Fellow AAAR & AGU. Aerosols, pollution #EndFossilFuels #COVIDisAirborne http://Bit.ly/FAQ-A  http://Bit.ly/c-est 

Boulder, CO
colorado.edu/chemistry/jose…
Joined July 2009

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    1. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      19/ A level of airborne virus is established in the room. Depends on: - how much virus is being exhaled - how big the room is - how quickly is the virus being removed Analogous to height of water in a sink, depends on flow from faucet, size of sink, and size of drain:pic.twitter.com/geIX5q7wlM

      9 replies 112 retweets 340 likes
      Show this thread
    2. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      20/ For those interested in more details and more references, the model is freely-available in spreadsheet format at http://tinyurl.com/covid-estimator  Useful for those familiar with spreadsheets and quantitative stuff. [Often confusing for those not familiar with those tools]

      1 reply 39 retweets 213 likes
      Show this thread
    3. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      21/ Multiple very similar models have been published (I'll add a list at the end), they all do the same thing. But one complexity is that the result depends on many parameters, hard to represent / summarizepic.twitter.com/3Gq05hh8dJ

      1 reply 23 retweets 154 likes
      Show this thread
    4. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      22/ This paper makes 2 advances: the first is that we condensed ALL the factors that affect infection into a single number: - The relative infection risk parameter (Hr)pic.twitter.com/6qGOL2IDqC

      1 reply 30 retweets 174 likes
      Show this thread
    5. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      23/ Where: - r_e: changes in virus emission (e.g. talking, singing) - r_b: changes in breathing rate ( changes virus inhaled, e.g. exercise) - f_e and f_i: for how many aerosols escape masks going out of the infected (e) and being inhaled by the susceptible (i) (=1 if no mask)pic.twitter.com/NTYDknNZw1

      3 replies 20 retweets 133 likes
      Show this thread
    6. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      24/ - D: duration of the event - V: volume of the room - lamba_0: ventilation rate - lambda_cle: air cleaning (e.g. HEPA filter, #corsirosentalbox, UV disinfection) - See paper for more detailspic.twitter.com/hjm9Py20xJ

      1 reply 18 retweets 132 likes
      Show this thread
    7. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      25/ The model predicts that the attack rate (fraction of people present that were infected) should depend on Hr only, for a GIVEN disease. Does that work? It does for COVID-19! Red line is model, datapoints are outbreaks [Ignore mitigation arrows for now]pic.twitter.com/xkGW3d3s5I

      3 replies 36 retweets 184 likes
      Show this thread
    8. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      26/ Agreement is not perfect, but these are outbreaks taken from the literature, with imperfect data about activities etc. Personally I was astounded when I saw this (@ZheP_AtmChem did a lot of the actual work)pic.twitter.com/eAs35byrmQ

      1 reply 29 retweets 181 likes
      Show this thread
    9. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      27/ Now, if these superspreading events were caused by e.g. surface transmission, or something else than airborne tr., THERE IS NO REASON why the model would be able to reproduce data So this confirms that superspreading events are dominated by shared room airborne transmissionpic.twitter.com/Vytu3NE8Bq

      2 replies 53 retweets 245 likes
      Show this thread
    10. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      28/ Why don't we have more events? This is a SORE point. Bc most investigations done by epidemiologists who do not understand ventilation. They don't report size of the room or ventilation rate. I've reached out to epi investigators of other outbreaks, most don't even reply.pic.twitter.com/jzKl5AIjWr

      3 replies 46 retweets 248 likes
      Show this thread
      Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

      29/ Now, as Kurt Lewin said, "there is nothing more practical than a good theory". Once the model works, we can use it to: - analyze other outbreaks - understand the risk of other events - quantitatively evaluate mitigation measures - compare with other diseases - etc.pic.twitter.com/a4LseSxAn8

      5:39 PM - 6 Jan 2022
      • 37 Retweets
      • 209 Likes
      • Malcolm James Zara B SarahJe The Real McCoy Sean P Casey David Thompson Adrian Engler John Cormier Tina Types Typos 🌁🌸🪴
      1 reply 37 retweets 209 likes
        1. New conversation
        2. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          30/ For example, in this table we estimate the risk of transmission of different situations, for the omicron variant with a 1% infection rate (approx. now in UK and US) [You can tweak it for your situation at http://tinyurl.com/covid-tables ]pic.twitter.com/Dsky6SQpgW

          10 replies 118 retweets 386 likes
          Show this thread
        3. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          31/ The table shows the probability of infection for an individual that participates in an event. - There may or may NOT be someone infected there: e.g. if 10 people present and 1% of population infected, then 90% of the time no one is infected, 10% of the time 1 infectedpic.twitter.com/ctPLxDxN7l

          5 replies 61 retweets 236 likes
          Show this thread
        4. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          32/ The rest of the factors are the ones that we have discussed already: - low vs high occupancy (more people, more change someone infected) - ventilation rate (outdoors vs indoors good vs indoors poor). Note that poor ventilation is the NORM, not the exception, even in USApic.twitter.com/Xv13gxASx3

          2 replies 21 retweets 127 likes
          Show this thread
        5. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          33/ - Wearing masks or not (masks remove exhaled virus and prevent inhalation of virus from the air) - Vocalization: much more virus exhaled if talking, shouting, exercise - Contact time: more virus accumulates in the air, and occupants breathe more air over longer timepic.twitter.com/vplq5AITir

          3 replies 25 retweets 119 likes
          Show this thread
        6. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          34/ This table updates a similar, but QUALITATIVE table published by @trishgreenhalgh, Lydia Bourouiba, and colleagues in a paper in @bmj_latest in 2020, that most of you have probably seen. We collaborated w/ them using model for new QUANTITATIVE table https://www.bmj.com/content/370/bmj.m3223 …pic.twitter.com/Lzrak94GO7

          2 replies 27 retweets 126 likes
          Show this thread
        7. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          35/ Another application of the model is to evaluate the impact of mitigation measures. I.e. we are told to spend less time, better mask, more ventilation, add HEPA filter. Confusing, one gets tired after doing a few things How much is enough? How much is risk reduced?pic.twitter.com/w67tWwOhpW

          1 reply 24 retweets 102 likes
          Show this thread
        8. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          36/ For example here we start with a high risk situation By using N95 masks (with attention to fit), halving the duration, and improving ventilation and filtration, we get to a situation where the probability of outbreak is quite low. Can rank benefit per $$ of each measurepic.twitter.com/JQlh3Xfq4c

          3 replies 40 retweets 124 likes
          Show this thread
        9. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          37/ In the paper we show similar mitigations for a range of locations, that comply with recent ASHRAE (@ashraenews) guidelines. Which is typically a BEST case scenario. Older places have less ventilation. And compliance only at construction, often things degradepic.twitter.com/wKKwDzv1BR

          2 replies 20 retweets 90 likes
          Show this thread
        10. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          38/ For example: - A lot harder to make choir safe: a lot of virus emission by singing, more breathing - Much easier to make library safe: much lower virus emission since no talking, sedentary, also inhaling less air Consistent w/ tons of choir outbreaks, none in libraries TMKpic.twitter.com/LF2IvjWexl

          5 replies 28 retweets 148 likes
          Show this thread
        11. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          39/ Finally, the model allows comparison of different airborne diseases: - Pulmonary tuberculosis is ONLY airborne - Measles superspreading is dominantly airborne - Flu is also airborne (https://www.science.org/doi/10.1126/science.abd9149 …)pic.twitter.com/4urUHOjR4e

          1 reply 25 retweets 108 likes
          Show this thread
        12. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          40/ COVID-19 has intermediate transmissibility between tuberculosis and measles Both are airborne. Which is why the old argument (made by e.g. @WHO experts https://aricjournal.biomedcentral.com/articles/10.1186/s13756-020-00779-6 …) "COVID-19 can't be airborne because it is less contagious than measles" never made any sensepic.twitter.com/uemLCbNtEN

          2 replies 36 retweets 144 likes
          Show this thread
        13. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          41/ We couldn't find many outbreaks in the literature for other diseases that DID have ventilation rate, room volume, and the other parameters we needed. But relative trend is clear. [If you know of other outbreaks w/ that info, email me the papers]pic.twitter.com/HbarF0JgLO

          1 reply 12 retweets 80 likes
          Show this thread
        14. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          Prof. Jose-Luis Jimenez Retweeted Prof. Jose-Luis Jimenez

          42/ The flu outbreak is the famous case in an airplane that was parked in a tarmac for 3 hours without ventilation, with someone coughing continuously: https://academic.oup.com/aje/article-abstract/110/1/1/62223?redirectedFrom=fulltext …https://twitter.com/jljcolorado/status/1391216930309087234 …

          Prof. Jose-Luis Jimenez added,

          Prof. Jose-Luis JimenezVerified account @jljcolorado
          77/ E.g. the flu, very important for its pandemic potential. Superspreading in plane: "A plane w/ 54 persons aboard was delayed on the ground for 3 hours without ventilation. Within 72 hours, 72% of passengers got the flu." https://academic.oup.com/aje/article-abstract/110/1/1/62223?redirectedFrom=fulltext … pic.twitter.com/YloKdiWr3t
          Show this thread
          1 reply 14 retweets 88 likes
          Show this thread
        15. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          43/ IMPORTANT: all of the outbreaks included in the paper are from early in the pandemic (it takes time to do the analysis and publish it), so they are all for the original (Wuhan) variant(s)pic.twitter.com/Xopwma6iMA

          1 reply 20 retweets 99 likes
          Show this thread
        16. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          44/ We can estimate the impact of the omicron variant, from recent reports of its increased transmissibility. Uncertain, clearly worse, but not like the few historical measles outbreaks yet (subject to update once we have O data): - Wuhan: central red line - Omicron: pink linepic.twitter.com/KfAQ8BEx9s

          2 replies 18 retweets 97 likes
          Show this thread
        17. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          Prof. Jose-Luis Jimenez Retweeted Prof. Jose-Luis Jimenez

          45/ So I think that's all I wanted to say. Thank you if you made it to here. For more info on the overall airborne transmission thread, you can see this other thread, and papers and threads linked therein:https://twitter.com/jljcolorado/status/1461356173081276420 …

          Prof. Jose-Luis Jimenez added,

          Prof. Jose-Luis JimenezVerified account @jljcolorado
          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.
          Show this thread
          1 reply 13 retweets 167 likes
          Show this thread
        18. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          Prof. Jose-Luis Jimenez Retweeted Prof. Jose-Luis Jimenez

          46/ If you mostly care about what you can do to protect yourself (hopefully it makes a little more sense now after reading about the model -- since if you made it here, you must be quantitatively minded), see this thread and its links:https://twitter.com/jljcolorado/status/1461356173081276420 …

          Prof. Jose-Luis Jimenez added,

          Prof. Jose-Luis JimenezVerified account @jljcolorado
          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.
          Show this thread
          3 replies 21 retweets 120 likes
          Show this thread
        19. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          47/ Finally I have to thank many people without whose hard work, input, and feedback this work wouldn't have been possible. - I started working on this idea when we were working on the paper (led by @ShellyMBoulder) of the Skagit Choir outbreak (https://onlinelibrary.wiley.com/doi/10.1111/ina.12751 …)

          2 replies 14 retweets 114 likes
          Show this thread
        20. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          48/ I kept working on it, but as they say in my native Spain, I was "slower than the horse of the bad guy" in a Western movie. I asked @ZheP_AtmChem to work on it w/ me. He did enormous amount of careful work to distill the results. I couldn't believe my eyes how well it workedpic.twitter.com/o94HmPls9B

          1 reply 13 retweets 106 likes
          Show this thread
        21. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          49/ Many other scientists also participated (and were very patient with me), most from Lidia Morawska's "group of 36" that met with @WHO on 3-Apr-2020, led the "Letter of the 239 scientists" etc. Including @ShellyMBoulder, @linseymarr, @WBahnfleth, @CathNoakes, @xqcgeo...

          1 reply 11 retweets 86 likes
          Show this thread
        22. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          50/ (authors continued) ... @Marcel_Loomans Giorgio Buonanno, Lidia Morawska, Stephanie Dancer, Yuguo Li, Bill Nazaroff, Chandra Sekhar, Raymond Tellier, Julian Tang. @apinedarojas and @KropffLab joined to help us treat uncertainties more rigorously, but had ton of useful input

          3 replies 8 retweets 74 likes
          Show this thread
        23. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          51/ As I said earlier we twisted the arms of @trishgreenhalgh and Lydia Bourouiba to join us to develop a quantitative version of the infection tablepic.twitter.com/mQlcwpOg5C

          4 replies 27 retweets 107 likes
          Show this thread
        24. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          52/ If you want to use the estimator at http://tinyurl.com/covid-estimator , see the readme and FAQ pages. A video explaining an earlier version of the estimator is here:https://www.youtube.com/watch?v=2acW7ruCRKM&t=2135s …

          2 replies 17 retweets 92 likes
          Show this thread
        25. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          53/ A version of the estimator video in Spanish is at: https://www.youtube.com/watch?v=u1pseoJHtSA … There are other related videos in my YouTube channel:https://www.youtube.com/c/JoseLuisJimenez/ …

          1 reply 14 retweets 64 likes
          Show this thread
        26. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 6

          54/ That's it for now. (I still need to add links for other estimators, but fam. waiting for me to finish to have dinner, patience is thin!) Again the paper is at https://pubs.acs.org/doi/full/10.1021/acs.est.1c06531 … If you want to ask questions, pls add the tag #Hpaper so that I can find them and reply

          16 replies 18 retweets 112 likes
          Show this thread
        27. Prof. Jose-Luis Jimenez‏Verified account @jljcolorado Jan 7

          55/ For those of you that use the estimator (http://Bit.ly/c-est ): - If you use the risk tables only, previous versions are fine (though v. 3.6.2 is easier to understand) - If you use the spreadsheets, please download the new version (v. 3.6.4), has some important updates

          7 replies 16 retweets 41 likes
          Show this thread
        28. End of conversation

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