1/ The State of Ventilation in the US as illustrated by a trip to the #AAAR2022 conference.
Just boarded @RideRTD bus to @DENAirport. 1/3 full, so far I am the only one with a mask (N95 Aura).
CO2 already quite high 5 min. after boarding even tho NOT full: poor ventilation...
2/ Still on @RideRTD bus to @DENAirport.
CO2 steadily climbing. Now over 2600 ppm, meaning >5% of the air we are breathing is "second hand", it has been in someone else's lungs before.
POOR ventilation. ~10 ppl masked our of 45, mostly KN95, few N95, 1 surgical.
#CovidCO2
3/ Made it to @DENAirport. Eating something outdoors so that I can remove the mask as little as possible in the terminal and the plane.
The CO2 sensor is measuring typical outdoor levels.
#CovidCO2
4/ At @DENAirport Main Terminal, by the security checkpoint.
Lots of ppl, 10% masked, mostly KN95.
Ventilation ok, though probably not good enough If we are going to rely on translation is the only layer of protection.
Hopefully there is some filtering.
#CovidCO2
5/ Train at @DENAirport from Main Terminal to Departure Terminal.
Crowded, very short ride... And poorly ventilated.
#CovidCO2
6/ Bathroom at @DENAirport. As I saw in a previous trip it is very poorly ventilated. No wonder it stinks in here!
@DENAirport, you need to do better on bathroom ventilation!
#CovidCO2
7/ Boarding @united. I was lucky to board early: CO2 was low, 700 ppm
Quickly going up. Little ventilation flow, so little filtering
Annoyingly @united personnel offered only a disinfecting towel when boarding... for a virus that transmits poorly, if at all, through surfaces!
8/ @united announcement: "Safety is our top priority"... as unmasked flight attendants perform safety demonstrations and CO2 stays high...
Ah, the irony!
#CovidCO2
9/ I do choose to fly @united, when I have to fly. NOT bc they are GOOD on safety on airborne diseases. But they are the LEAST BAD of the options available to me. @SouthwestAir seems to be much worse, per CO2 measurements that people have posted. Or e.g.:
10/ I regularly encounter some ppl, especially in the US, who have never heard of CO2 as a tracer of ventilation, and about its use as a surrogate of airborne disease transmission potential.
This article and thread give some bakground:
11/ I have chosen to go to #AAAR2022 (Annual Conference of @AmericanAerosol) in part bc I expect it to be pretty safe: masks are required everywhere indoors, and vaccination is also required.
12/ Not surprising: we understand airborne transmission
Unlike conferences from fields that mostly DO NOT understand airborne transmission (e.g. American @PublicHealth Assoc., some medical conferences) where masks are not required... & often turn into superspreading events
13/ Although I am glad to see that @IDWeek2022, an upcoming major infectious disease conference, does require well-fitting masks and vaccination too. Maybe we are getting through, if slowly.
idweek.zendesk.com/hc/en-us/artic…
14/ But unfortunately this is indeed still pretty common:
15/ During the @united flight CO2 stayed around 1100-1400 ppm. Not great, but not terrible given the HEPA filtering (which should be on when plane is on the air -- unlike being OFF when we boarded). And less bad than other airlines.
16/ Arrived to @sheratonhotels
Unfortunately CO2 in room is elevated. Either air recirculation thru filter (if I am lucky), or infiltration from other rooms (if less lucky), like studies where ppl got COVID from ppl their never met in quarantine hotels:
wwwnc.cdc.gov/eid/article/28…
17/ Day 1 of the #AAAR2022 (American Association for Aerosol Research @AmericanAerosol) Conference.
Picking up lunch at @jimmyjohns in Raleigh, NC (to eat outdoors).
Quite a few ppl, good ventilation.
18/ At the @AerodyneRes Mini Users Meeting at the #AAAR2022 conference.
40 ppl at Raleigh Convention Center @Raleigh_CC. Large room, high ceiling, ventilation is on.
CO2 staying low.
EVERYONE is masked (required), 1/2 KN95, 40% N95, 10% other (surgical and cloth). [Quite safe]
19/ Just arrived into my room ar @sheratonhotels after being away all day. Same as yesterday, CO2 is elevated, indicating some recirculation.
20/ Plenary Lecture at #AAAR2002 at @Raleigh_CC.
500 ppl in large room, good ventilation (~700 ppm CO2)
Everyone masked and vaccinated, so feeling quite safe. Much more welcoming for ppl at higher risk to be able to attend in person.
#CovidCO2
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