A lot of people still think about Covid as a wash your hands and socially distance kind of thing.
Chances of getting Covid from touching something is near zero and we're far more likely to catch it from someone we can't see because it can stay in the air for a long time, drift long distances, and remain potent long after a contagious person is gone (as much as 2 hours).
This is why improving ventilation is one of the most important things you can do to reduce risks of infection for yourself and people around you. With good air flow, an infectious person is less dangerous. Infected air is diluted and can't linger to keep infecting.
I took a variety of CO2 readings to estimate indoor air quality. Based on these readings, places I wouldn't want to be unmasked would be: house gatherings, offices, meeting rooms, conventions, public transit, a plane, funerals.
Places that may not be as risky as originally believed are: supermarkets, pharmacies, and restaurants.
@sysop408@gemelliz in France they have these awesome posters that tell people to open the windows every x minutes (don't remember if it's 20 or 30) for a few minutes if they are gathering indoors. My CO2 monitor goes crazy in winter if I am cooking (with gas) - I have to run the fan or crack a window. And, just yesterday I was at a lunch where it was cold to start and then so warm with all the bodies that someone thankfully opened a door. So - I imagine the CO2 levels would have been high.
@sysop408 It’s worth adding that some research suggests that viral load is significant. Prolonged contact is bad, high concentrations are worse than low concentrations. Masks help. HEPA filters help. Fresh air helps. #SwissCheeseModel #COVID19#covid
@sysop408 this is very informative and helpful. Thank you so much for sharing! We are having a flu season in Jakarta right now, but this time it’s a bit strange. Because we have so much phlegm and the sickness can last for 7-14 days. Since nobody is doing a swab test anymore, I’m just suspecting this is another wave of mutated covid. Since it’s been 3 months since the last wave ended.
One surprising finding I'm having from taking CO2 readings in various places is that I'm consistently getting readings between 700 and 800 ppm at supermarkets.
I mostly took readings at peak hours. I'll need to go back at off peak times to see how much the readings change. I was really amazed at how "not terrible" the reading at Trader Joe's was.
Picture 1: Trader Joes at noon on a Saturday. It is packed. It was a total surprise to see CO2 readings between 700 and 800ppm! (Fair)
Picture 2: Smart and Final, a mostly California-bases grocery outlet selling a mix of regular groceries and bulk package items with a reading of 714ppm. (Good)
Picture 3: Walgreens Pharmacy, at off peak hours. 529ppm. This is very good, but hard to believe. I'll have to go take this again.
Picture 4: Nob Hill Foods, a small grocery chain in Northern California. 726ppm. Good-Fair.
@sysop408 produce gives off CO2. I’m not surprised Trader Joe’s had a lower rate because it generally has less produce. Either way I’m not a scientist and don’t take my word for it.
I'm making some blunt assumptions about what these readings mean. From what I've been gathering from scientists posting about air quality readings, 400ppm is a baseline and every +200ppm gets you from excellent to good to fair to unhealthy.
Most people seem to be suggesting 800 and below as the line to really start exercising more strict caution if you're trying to avoid infection.
But keep in mind that's based on 400ppm as the baseline. My baseline for some of these readings is shown in the attached photo. It's 470ppm outdoors on that day.
My baseline is likely higher because I'm in an urban area at a mall near very busy roads. There's a lot of extra ambient CO2 so my cutoff lines would be 670 and below (excellent), 870 and below (good), 1070 and below (fair).
Every 400ppm above baseline roughly equates to 1% of the air you breathe being exhaled by someone else. That's like getting mouth to mouth once every 6-8 mins.
Want to see what a CO2 chart for an office meeting with about 12 people for one hour looks like? We start with excellent indoor air quality at 9am with 500ppm of CO2.
After one hour in a poorly ventilated space, the CO2 readings are 1720ppm! And this is a fairly spacious office that would have a bit of air reservoir to slow down the rise in CO2 levels.
Yikes! This means everyone is breathing quite a bit out of each other's lungs. If you're only going to wear a mask in the riskiest situations, this should be one of them.
Keep in mind that just having high CO2 concentrations doesn't mean much unless someone is contagious in the room, but if there was someone contagious that day, lots of people in that meeting would have gotten whatever was being passed into the air be it Covid, flu, RSV, or a cold.
@sysop408 it's bad for other indoor air hazards like VOCs or mould. If there is a ventilation system, it's likely broken so you may be at risk for legionnaires disease.
@sysop408@ingalls This looks like my classroom - 26 kids, 70-year-old school, windows sealed shut, no A/C. They tested the CO2 over several days, came back & retested the next week because they thought there was an error. No error. Explains why we're all sluggish & sleepy by midafternoon, especially on hot days, & reinforces why I stay masked inside at school.
@Nshrubs@ingalls I've only been toying with this so it'd be awfully precious of me to think I know anything from this, but it sure does appear like classrooms are one of our biggest risks that we're barely doing anything about.
It seems like a lot of people who took at least some precautions managed to remain Novids untl their kids brought it home.
@sysop408
Yeah there's only so much you can do as parents, you can't lock your kids up at home as that's awful for their development, but you also have to pretty much accept what their school or daycare is doing.
I guess because COVID is supposedly (largely, I know tragically not for many) less bad for kids, they've been stuck with the short end of the stick.
@sarajw one reason for optimism is that if there are long term impacts, so many people will be affected that there’ll be lots of medical research and likely therapies.
@sysop408@sarajw@ingalls I've had several students develop long term effects after just one infection. One of my former 2nd graders got it pre-vaccine. Now has asthma, inhaler in the nurse's office. Another former student basically has chronic fatigue/long COVID & only comes to school 3-4 days a week now. Another one has had GI issues ever since she had COVID. Just the tip of the iceberg.
@sysop408@Nshrubs@ingalls That is my one big fear - that once the kids go back, we will get sick all the time. Except for one strange instance, we have not been sick at all in three entire years.
@sysop408@Nshrubs@ingalls They we’re given billions in grant money for school air quality improvement. It remains largely unspent. Some GOP controlled schools have even rejected gift of Corsi boxes. We all need to be pressuring them at local levels. Please don’t say discard the notion of masks, that’s insane. ALL the measures should be observed. No one is hurt by wearing a mask while we work on improving air but lots can be if those who are wearing them stop
@Pineywoozle ah, so notice this thread is simply focused on ventilation. I'm intentionally mostly avoiding the masking conversation. If you understand how masks do and don't work, we're on the same page and the conversation I'm trying to have is with the person next to you.
@sysop408@Nshrubs@ingalls This was the part that I was addressing - “A lot of people still think about Covid as a wash your hands and socially distance kind of thing. Please throw that out”
Nothing should be thrown out. If you suggest it for one thing like social distancing it translates to “Oh I don’t need to take in person precautions” Current vaccines work better against the new variant the lower you keep your viral load. It all matters.
@Pineywoozle keep washing your hands, but don't do it because you think it's helping you avoid Covid. Tons of people still think that's a key infection pathway. To this day, we have yet to conclusively identify cases that were from fomites. I'm sure they're out there, but it's rare.
Because of the work I do with small businesses, I deal with the world at a retail level. Tell someone to do three things and they may get overwhelmed and do none of them. My message isn't about being perfect. It's about what has a chance of getting through to the many people who tuned out sometime in December 2020.
There are plenty good reasons to wash your hands, but it may actually be harmful messaging if it causes some people to focus on it at the detriment of avoiding enclosed spaces with stale air. I started this thread after being with friends who were all unmasked in a room talking about how they kept washing their hands because they didn't want to get Covid again.
@sysop408@Nshrubs@ingalls I understand how low the fomite route is. I also dealt w/ boutiques for a decade & I agree people are overwhelmed by too much info but they also infer things that are close to what’s said but way off the mark & that’s the part I was addressing. You saying “Throw that out” is going to hit a lot of brains as the message “social distancing doesn’t matter so masks must not either.” Untill air quality improves all of what we say matters
@Pineywoozle here's the reason why I de-prioritize social distancing when I'm trying to get people to focus on the one single most effective societal level intervention.
Social distancing protects you from close contact transmission which is a lot less common than the typical story of "I have no idea how I got it. Nobody around me seemed sick and I didn't get too close to anyone!"
In my area at peak pandemic when there was plenty of testing and monitoring, the chances of coming face to face with an infectious person was likely much much less than 1 in 100 on the average. Chances of you entering the same space as an infectious person? Quite high.
Infections tend to cluster in populations so once it enters your social group, your chances of direct contact do go way up, but your risks from indirect contact are always going to be orders of magnitude higher.
I don't find social distancing messaging to be helpful in 2023. It's correct, but I don't find it effective at the population level.
@sysop408@Nshrubs@ingalls I get all that. Literally all I was addressing was that if you say “throw that out” You think your just deprioritizing and people will take it as permission to throw out way more than you intend. The general public is always playing a game of telephone and the message is always garbled. Emphasize the stuff about air quality for sure but for my money you should guard against what you see as harmless deprioritizing.
@sysop408@Nshrubs@ingalls I really liked your posts and honestly it wasn’t ment as a bad criticism just me sharing how easily it could be misconstrued. We’re all in this together🥰
@sysop408 there's also a potentially significant cognitive impairment with that kind of CO₂ level—best to not take any important decisions in that meeting…
@sysop408 Even without covid or other airborne communicable diseases, it means less oxygen per brain in the room, which makes people tired and irritable, increasing workplace tensions.
I'm sharing all of this with you because we could still be in for another wave and lots of people have waned immunity and prior infection isn't good at keeping you from getting a next infection.
It's also because I'm realizing among my real world friends that some are still focusing on hand washing to avoid getting Covid.
They're also trading lower risk activities for higher risk ones because they don't understand how it works. My friends who do catering told me they were catering huge house parties every day during the height of the pandemic when restaurants were closed for dine-in.
Restaurants have modern HVAC systems and have to pass building inspections. I've been surprised that readings in most restaurants are quite good (off peak at least). Very few homes will have ventilation systems like those in even a run down restaurant.
Going to a house party instead of meeting at a restaurant is a bad trade-off!
I spent some time inside a variety of food/retail businesses this week as a photographer. Here's an #Aranet4#CO2 reading from a bakery where the owner is very Covid conscious. She keeps it very well ventilated. This small bakery cafe was at full capacity with 15+ people. The CO2 reading was 471ppm against an outside reading of 415ppm.
Front door open w/commercial kitchen in the back pumping air. That it was windy also helped.
Also took a reading deep in a packed small Thai restaurant w/Covid aware owner. 550ppm, door open + all windows 1/4 open. Very surprised it was that low.
I've yet to measure a restaurant exceeding 800ppm (which is roughly 1% of re-breathed air per breath).
I may eventually feel just fine dining indoors in some places once we have some more clarity with the direction that #Covid & therapies are heading. On the flip side, there are types of places that often have bad airflow that I'm never looking at the same again.
@sysop408 when my knee is bad I take the elevator between subway platform and street. Or I would, if people would mask there.
One time I passed on the elevator 2x to avoid that confined space with unmasked people (who've been unmasked all day and all week, who knows what they're exhaling?*). The third time I gave up and walked the stairs despite my knee.
studies show: up to 20% of #covid19 cases are asymptomatic 😱
Please mask in enclosed spaces, folks. 😷
If not for you, then for me.
@kcarruthers is it as eye opening for you as it is for me? Have you found any trends that made you stop and wonder?
That the last two eye clinics I visited were on the higher end of my readings was a real surprise. It was only two locations and I'm not going to throw all eye clinics under the bus, but perhaps they fit into a retail category where the environmental requirements of the business make it more likely to trend toward looser ventilation standards.
I've been on this crusade for years now. I believe "rebreathed air" or "air straight from someone else's lungs" needs to be something we talk more about.
Here's a link to a spreadsheet that I've been sending to people recently from @DavidElfstrom:
@RolfBly@sysop408@BE Really simple version is for every 400ppm above 400ppm, it's +1% rebreathed air. The shape of the curve over time is useful as well, it related to the total volume and air exchange rate. The time it takes to level off at a constant value represents about 3 air changes. So if it takes 30 minutes to reach a constant level, that means there's 6 air changes per hour.
@sysop408 Obviously CO2 is a reasonable proxy for ventilation in public spaces, but I wonder how precisely that correlates with risk of infection when said space is a crowded supermarket and you're waiting in a checkout line with lots of unmasked people on every side of you. It seems quite possible that CO2 levels could be quite reasonable and there still be some #COVID or other nasties floating in the air. For now I'm going to err on the side of caution while grocery shopping.
@BruceMirken you're right. All things are relative here. What we have here are degrees of risk, not degrees of safety.
The reason why I'm asking people who got stuck on conceptualizing risk in social distancing terms to drop it is not because all risks are equal.
The person right in your face is definitely a more potent risk, but if we're playing just the numbers game, only a handful of people can be in your face, but hundreds of people can be close enough to infect you if the air quality is poor. Yet people mostly look at what's in front of them.
Even during heavy spikes in 2020, in most places, at any given time there were fewer than 1 out of every 100 people who were likely to be highly contagious. Chances of being face to face with that 1 in 100? Small, especially if the symptomatic ones self quarantine or try not to get too close to anyone. Chance of ending up in the same room? Quite high.
That's the point here and some people who are trying to balance risk with reward need to understand that.
@sysop408@BruceMirken the good thing with ventilation and the CO2 proxy is that it's one of those things we would benefit from even if COVID wasn't an issue (a similar thing hold for washing hands, BTW, good hygiene practices transcend the specific ailment). So it's good to learn more about the specifics of COVID transmission, but it's also good that good practices are kept in mind and good habits reach as far and wide as possible.
@sysop408@BruceMirken unfortunately for us survivors, the early strains of the NCOV2 virus were very non-contagious compared to the current stuff circulating. Indoor air concentrations of things. Definitely more of an issue now. The main reason why there were so many cases and deaths in 2020 is because A: horrible patchwork of response. B: No vaccine. And C: Healthcare overwhelmed.
@sysop408 FWIW my two Aranets, like yours, consistently read 450-500 outdoors in the city of Eugene, OR. The same device read 419 at Willamette Pass ski resort (cleaner air, higher elevation). And it read 330 in Truckee, CA (+7000'). My point is, you're right, the local baseline is relative and your calibration probably isn't off. But being off by 100 still wouldn't justify a classroom (for example) being at 1000, or 1500 like my kid's brand new school was every day last year.
@surfingreg 1000+ in a new school in our day and age when we should know better!!!
That’s just awful. A number of my friends who were Novids and were only taking precautions, but no strict safety measures finally caught it from their kids.
@surfingreg@sysop408 Temperature, pressure and relative humidity affect how well the NDIR CO2 sensor operates. Which is why good sensors track these points to make adjustments.
@sysop408@surfingreg I have two different brands of dual-NDIR sensors, and I’ve seen them both drift 100ppm outside in the same location on different days, but be consistent with each other largely.
I assume it does account for it, it has the 4 sensors needed. The software that glues each brand’s package of sensors together has the magic that glues the data together.
No, it”s really not. I have been monitoring CO2 levels with an Aranet monitor just like this one for three years. 400-420 is a pretty typical outdoor reading and is what I get in my rural location in Alberta.
Ok, you're in rural Alberta. I'm in a highly car dependent area of Northern California. You can't see it in this photo showing 471 ppm CO2, but to my left is a major road. Behind me is a major road. In every direction is a rippling ocean of cars looking for a parking space.
I was getting outdoor readings of 460-510ppm constantly. I thought I might have been breathing on it so I took precautions to avoid influencing the results.
Yes, it was 471ppm. No, it's not 470ppm everywhere around here and it's not even 470ppm on other days, but on this day it was.
@MikeEL to some extent, you can indeed smell when a place is stuffy, but I could probably only estimate if something was above 1000 or below 1000.
There are also other signs though. One of my higher indoor readings at the mall was at TJ Maxx which was near the 1000 line. I could tell it wasn't going to be a good reading right away because it was noticeably warmer and more humid in there than in the rest of the mall.
I've only started doing this so I'll probably have a better idea in a few months. I am hoping to develop a natural sense of whether a space is well ventilated or not.
@MikeEL I've been a few elevators, but the rides were so short the readings wouldn't be valid. I'll try to mope around in the next one I'm in and send you a reading.
That said, the readings I have that were specific to elevators have usually been better than the air in the areas outside of them. Current day elevators have pretty good ventilation.
Another possibility is that they were doing some disinfecting routines that triggered your allergies. Sometime around 2022 I finally realized why my eyes were burning all the time when I went shopping.
I hadn't realized how much surface disinfecting was going on. There was always some cleaning agent in the air everywhere I was going and I'm very sensitive to that stuff.
There you have it. Could be counter-intuitive reasons! And yes, there was noticeable disinfectant in the halls.
I have trouble with oxygen saturation that actually causes vision trouble. Have not yet pinpointed the cause of low blood saturation levels. Doctors suspect sleep apnea.
@sysop408 I've also been pleasantly surprised by my Aranet readings in my local supermarket and drugstores. I still mask, but I'm less worried than I would have been otherwise.
@jeridansky I'm wearing a mask for the forseeable future too. I decided to start doing this to gather data points to help me decide how to navigate the next phase of the pandemic and (hopefully) eventually to fewer precautions.
I've been most pleasantly surprised readings were so low in the restaurants that I've gotten takeout orders from, but I guess I shouldn't be too surprised once I think about it. Kitchens are inherently messy and smelly so even before we consider that they have to pass HVAC inspections, every restaurant's air flow is already being influenced by the needs of the kitchen.
It's not going to be this year, but I have hope that I'll be able to go enjoy a restaurant again.
What kind of readings are you seeing at grocery and drug stores?
@sysop408 I haven't checked recently, but I was getting 490-610 at the drugstores, 633 at the grocery store. Also 692 at the Apple store!
I get great readings at my dentist and periodontist because I've trained them to open the window in the room I'll be in. (I'm fortunate that they are both in buildings with windows that open.)
@sysop408 And yeah, I'm still doing takeout or well-spaced outdoor dining. I'd love to feel OK about eating in a restaurant, but I can't see that happening any time soon.
@sysop408 During the very beginning of the pandemic at Trader Joes, they had their ventilation system basically cranked all the way up, and you could tell that they were mixing outdoor air with their air-conditioning air. You could actually feel the air flow in the store. Sadly, as time went on, we realised that we needed to do curbside or delivery to reduce risk. Trader Joes does not offer either of these things, so they were the last store I went shopping in.
@sysop408 This is fascinating & I need to start doing this. Why did you choose this particular #aranet4 CO2 monitor - there are a bunch of different ones & I don't know what I'm choosing from. Obviously non portable ones are useless so I can exclude them no matter what their quality.
@sysop408 That might be the best ventilated Trader Joe’s in the country. I took my Aranet4 to a bunch of grocery stores a few months ago and all except TJ’s were in the 600-900 range, but the best reading I got (early morning) in a TJ’s was 1175 and it was usually 1300-1500… enough CO2 to measurably reduce cognitive function even if you’re not worried about COVID.
@PedestrianError I want to go back and try that one again because that didn't seem right to me. It was in a new-ish building though and it was a TJ's right from the start as opposed to one that was stuffed into a vacant box. I need to also try other TJ's too.
Also these are all in suburban spaces. A packed TJ's for me is probably hold my beer TJ's in Manhattan.
Took some #Aranet4 readings in some places I visited previously, except this time it's the height of the holiday shopping season and those places were all jam packed.
The food court at the mall, normally a relatively safe 625ppm, now reads 1043ppm. The actual recorded peak was 1152 & true peak's probably much higher.
I was only at the periphery. Even with an N95, I didn't want to dive into the mass of humanity because it was physically uncomfortable. It felt notably hot & humid as you got closer to the center.
This mall is NEVER this full. They were hosting a maker's fair. In addition to normal holiday shoppers, every Etsy maker in the area and their supportive friends came. Good mask strongly advised in these situations!
On the positive, at 2 Target stores on a peak shopping weekend, the max reading at the very back of one was 960 and more tame 750 near the front. At another Target, the peak was 850 (only about 100 higher than previous readings there taken during more moderate demand).
Some math for those who aren’t familiar with the numbers. 420ppm is the baseline. Every 400 above that represents 1% of rebreathed air per breath.
Average person breathes about 15x a minute. At 820ppm (1% rebreathed), it takes about 7 minutes for you to take a lungful of secondhand air. At 1220ppm (2% rebreathed) it’s closer to 3 minutes.
HEPA filters can mitigate risk and clean the air, but some research at Bristol University recently showed why fresh air is still important. They found that the Covid virus dies 4x faster in less acidic environments. Exhaled breath is acidic so the more exhaled breath trapped in with you, the more acidic the air around you becomes.
Fresh air is not acidic and not as friendly to sustaining Covid (and possibly other respiratory viruses too).
What is interesting and instructive about that series of pictures is that there is no way to tell the difference just by looking at those spaces. The idea (which was out there) that you can bring a mask and then make a judgement ‘on the spot’ to put it on in a risky setting (or to not wear it if it’s a ’good’ place) is just deciding not to mask without admitting that that’s what you’re doing.
@sysop408 I think supermarkets generally have better ventilation than you'd expect because even just the faintest whiff of spoilage or decay is a profit killer.
@ratgrrl I'm starting to believe that numerous types of businesses had needs for high levels of ventilation that existed before the pandemic just as a result of what they needed to do to be an attractive business.
I thought coffee shops would be pretty bad because people tend to hang out in there and most of them don't have kitchens and all the fans that come with them.
But then I realized that while a few servings of coffee or espresso smells great, a few hundred cups of smells like something's on fire.
I noticed the last 2 optometry spaces I visited to be a bit high. I wonder if that's because they're basically office spaces that get retail level foot traffic.
@sysop408 supermarkets tend to have good air filtration, better then WalMart, though I can't speak for all WalMarts, and try to minimize my contact with them
@zdl, I understand there were many reports of transmissions in restaurants. They were well studied with infections mapped to air flow patterns, but is that really where most of the spread was happening? It seems we focused on one source of transmission, while overlooking others.
It could be time to re-examine our assumptions. We don't know how well ventilated those studied restaurants were. If I recall, Japan was always lax about their restaurants and yet they had no huge outbreaks until 2022.
We always knew restaurants were a source, but were they as central of a source as was believed? When we start with no information, we can over assign importance to the first thing we discover.
It's also possible that the restaurants I visited have improved their ventilation practices since 2020 and they're not the same places they were then.
Don't get me wrong, I'm still not dining indoors anytime soon, but I'm beginning to believe that I should be more suspicious of other places.
@zdl so I don't want to be impolite, but are we sure Chinese authorities aren't withholding some information? I find it hard to believe that if restaurants and shops are nearly 100% of the spread that buses, trains, factories, and offices aren't also significant sources.
I know things are much more clamped down over there, but just how clear that information is for something as chaotic as a respiratory virus would make me believe there's something being overlooked or hidden.
That said, I completely believe that many restaurants are much more risky than the ones I've visited whether we're talking China or the US alike. I can only generalize that what's in front of me is hard to align with restaurants being the primary source for infections right now where I live.
That's no crackpot theory. That was the going assumption here too when restaurants were ordered to only do takeout business, but here where the government doesn't have as much control, that just drove some people to order out and have parties at people's houses, which is going to be worse because nobody's going to have a commercial HVAC system in their house.
What's a typical restaurant in Wuhan like? How many people does it seat and how busy is it?
@zdl oh no it makes a lot of sense. Add to it that busy restaurants are noisy and that causes people to shout which ejects more aerosols and farther. Places where people speak less or are less active will have fewer aerosols.
@zdl yikes! I do speak enough Mandarin to know 热闹. I never thought about it as having a literal origin. Is it literally so packed that it's hot? If it is, would it be feasible to reduce capacity or refit the spaces to push more air through it?
@sysop408 Where did you buy that sensor? I'm thinking of getting one.
Also, if you have kids, have you tested their schools? I'm guessing that many schools didn't really spend all that much money on HVAC upgrades to improve air circulation. But I could be wrong.
@mvilain I got the Aranet4 on Amazon. It's pretty much the top of the line one for consumer use and it's pricey ($200-$250 US). There are cheaper ones that are still accurate, but have some drawbacks and poor battery life.
Yeah schools... Ugh. I know several people who only took basic precautions and still never got Covid until their kids brought it home.
I don't have kids, but see @surfingreg's post below where he says that he sampled his kid's brand new school at 1500ppm daily (almost 3% of rebreathed air per breath).
I can understand old buildings, but we gotta do better with our new buildings.
@mvilain take a look at the Vitalight Mini if you want something inexpensive, but accurate with some drawbacks. It has the same type of premium sensor that's in the Aranet4, but its operation and battery life leave much to be desired.
The Aranet4's price changes a lot. I got mine for $185. It was originally $150 before it became popular. Now it seems to be anywhere between $180 and $250 depending on when you buy it.
Here's a guy in New Zealand who did some great reviews comparing CO2 monitors.
@sysop408@mvilain Nice! I actually ordered an Atmotube Pro this morning. Wish I'd seen this review but I'll keep you all posted when it arrives. My goal, like with CO2, was to send something unobtrusive to school with my kid without freaking out the teacher.
@Mirjam_008 do what model do you have? Is there a link to it online? I've already long had HEPA filters around the house to deal with allergens and wildfire smoke, but they're not very portable.
@sysop408 In the end though, if unmasked people could at least just give me some room I'd still feel a whole lot better. Around here they get right up on you without even a thought. Like not even specifically trying to be rude even, just simply casually get right up on you, inches away. (Honestly I wish people would stop doing that regardless, but especially with a major global pandemic that has killed millions of people...)
@sysop408 They figured out cholera 150 years ago and rethought wells in London- stopped its spread. Have we learned nothing, or have we lost our will and/or leadership?
@sysop408 Planes at least are supposed to use filters which remove pathogens, including Covid, without removing CO2, and so may not be as bad as the reading would suggest.
@BenAveling and planes have filtration zones, it have you seen the real world readings coming back from people sampling CO2 on planes, upon boarding, and at the terminal? My trust level in planes as being protective by way of advanced engineering is dented.
@sysop408@lisamelton This is good and useful citizen research, but be wary of not advising caution about restaurants. Indoor CO2 levels are essentially a proxy for the concentration of exhaled air, and it is definitely advisable to avoid high concentrations, but it doesn’t necessarily follow that low levels indicate safety. Eating, talking, singing, and exercising all significantly increase the amount of virus being shed by a contagious person.
@sysop408@lisamelton Even if the contaminated air is being circulated away fairly quickly, if you’re stationary , seated near such a high-volume source, you’re in significantly more danger than if you’re walking around a grocery store.
Hi, whilst the media has generally moved on from reporting about #SarsCoV2 (until, or if, there is a variant that has a higher mortality rate. e.g., bypasses all vaccines), can you recommend any websites that are tracking Covid mortality rates?
@OskarImKeller my restaurant readings should be taken with skepticism because I wasn't there eating. In most of those places, I only took readings waiting for take-out and mostly off-peak hours. I took care to get far away from the door.
The highest reading I got was 675ppm standing in line for 5 minutes at a coffee shop that was busy enough that it took me over 5 minutes to place my order and pick it up. At a burger restaurant with 12 people dining and about 6 employees it was around 625ppm.
I was at a wine bar for a meeting with 10 people for 2 hours before they opened. They had a window open and the hood in the kitchen running. Average reading was 600ppm with a high of 675ppm.
I have yet to record a reading above 700ppm at a restaurant during operating hours. Most of my readings are in the 500-600ppm range probably owing to strong HVAC systems needed for a hospitality space and the kitchen needing lots of air.
I'm sure this isn't universal, but my limited encounters were pleasantly surprising.
Thanks for the explanation. I will stay cautious when it comes to indoor dining. Would have been interested to get readings from a table full of people. The effects of HVAC are most likely different in different parts of a restaurant is my gut feeling.
As for a table full of people, I do have one of that. It was the wine bar I had a 10 person 2 hour meeting at. We were not gathered as close as a dining party would be, but we spent 2 hours shouting to be heard like you would at a busy restaurant.
The readings were in the 500’s the first hour because it was off to the side. Someone was curious about my Aranet4 so I put it in the middle so were were all breathing at it the second hour. That gave me readings in the 600’s.
You can change the settings to make your Aranet4 take a reading once a minute. You can also change the green, yellow, and red threshholds and set a bell to go off if it hits the red zone.
In many places, the time of day matters a lot too. There are some places I've gone that appear to be well ventilated, but it's more a factor of the building being cavernous so if you go late in the day after all of the reserve capacity is used up, the readings are much worse.
I have been pleased that many places that normally handle high foot traffic did remain within 400 ppm of their normal readings even under very demanding conditions. I went to a general-merchandise store late on Christmas eve. The store was ransacked, still crowded, but held steady below 1100ppm.
Those aren't good numbers of course, but given the circumstances they're better than I expected. I put on an N95 and intentionally went at the worst time I could think of.
@sysop408 We changed the threshold and have also added the front sticker that calculates the levels of re-breathed air. They are very helpful when I take the #Aranet along to offices or meetings, as they communicate the necessity to ventilate without me having to do all the talking.
People talking or laughing also makes a difference. Best example is me on my desk alone or me on my desk in a phone call or video conference. That, as well as the HVAC, is why most larger shops are relatively okay.
@OskarImKeller did the sticker come with the Aranet or did you get it from somewhere else?
There's someone in Canada who's selling 3D printed carrying cases for Aranet4's at cost. I got one of them. There's not much difference between the numbers I got when I carried it ia loose side pocket vs clipped to my bag, but I like it somewhere visible so people will see it and maybe ask about it.
@juergen_hubert@sysop408 if you are properly wearing a proper FFP2 or N95 mask, you’re fine. Just make sure the mask stays clean/dry and you change it out about once a month. If it gets wet, change it asap. If it is super humid & damp out, you might want to think about changing out sooner, as moisture buildup reduces the filtration effectiveness.
Add comment