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Thank you for this extensive resource on air quality. Yes, it needs to get more attention as it is one of the main drivers of mortality of environmental risks.
by ahaucnx 5y ago
Thank you for this extensive resource on air quality. Yes, it needs to get more attention as it is one of the main drivers of mortality of environmental risks.
One thing one has to bear in mind is that often when you optmize your home for low PM (e.g. with air purifiers and fixing of air leackage) your CO2 will get very high causing headaches and reduce cognitive performance.
So it always makes sense for indoor air quality monitoring to measure PM and CO2 in parallel.
We have open source, open hardware build instructions for a very reliable Air quality sensor that can be used to measure PM2.5 and also CO2 [1]. It is very accurate for the fraction of the costs of commercial sensors. You can build it for less than USD 20 (or with CO2 for less than USD 50) and send the data to our cloud server or any other backend.
I am more than happy to send you some free PCBs (you just paypal me the cost of the postage) and you can build your own sensor and log the data. Contact me if you are interested.
[1] https://www.airgradient.com/diy/ https://www.airgradient.com/diy/
- briefcomment 5y agoI've seen a study or two that claim that the bulk of some PM, like brake dust for example, is much smaller than 2.5um. Having exposure to the industry, do you have hopes for sensors that can identify smaller particles than .3um (that's the smallest Purple Air goes).
- eindiran 5y agoHow should someone contact you? I looked into setting up something on an Arduino last year, and the CO2 sensor I ended up purchasing was not very good, so it's cool to see someone thinking about this problem domain.
- scaladev 5y agoFWIW I've been pretty happy with Senseair S8 0053 for my DIY stations. They're relatively expensive though. Not affiliated in any way.
- ahaucnx 5y agoYes the Senseair S8 is very good. Only problem is that the automatic baseline calibration sometimes needs 7-10 days to kick in. But you can also do a manual calibration.
- ahaucnx 5y agoWe use the Senseair S8 CO2 sensor which is very accurate and of high quality. Some of the TVOC sensors give an estimated CO2 level (eCO2) which is not recommended because these values are not very accurate. To send me a message please go to https://www.airgradient.com/diy/ https://www.airgradient.com/diy/ and send me a message with the orange chat button. Thanks!
- joshmlewis 5y agoWhat is your PayPal?
- tehnub 5y agoIn practice, how does one try to achieve a balance between CO2 and PM? Do you open the windows for a while when CO2 is up and PM is down, and then close them and run your purifiers when CO2 starts to go back down? Is it possible to keep both low with HEPA filters on the windows?
- simondotau 5y agoThe best case solution would be a passive house with MVHR (Mechanical Ventilation with Heat Recovery) and incoming air filtration. This means your home has a steady flow of fresh, low-CO2 air that is filtered for pollen and other particles (depending on the air filter chosen).
- laurent92 5y agoThis. Architects now include heat exchangers in houses, so air is renewed at basically the same temperature, ensuring ideal comfort for low CO2.
- ahaucnx 5y agoAnother solution is to install a positive pressure system with high performance HEPA filters. This is especially recommended if you live in areas with very high air pollution. Positive pressure systems can virtually achieve zero AQI inside even on the worst polluted days. You can read more here: [1] https://www.airgradient.com/blog/2020/01/08/positive-pressure-systems-for-clean-air/ https://www.airgradient.com/blog/2020/01/08/positive-pressur... [2] https://seetheair.wordpress.com/2021/04/26/thailand-school-sets-the-aq-bar-high-an-example-to-be-followed/ https://seetheair.wordpress.com/2021/04/26/thailand-school-s...
- clairity 5y agoco2 and pm should both go down with windows open. i put my air purifiers on low when the windows are open to deal with the particles i throw up by moving around and doing stuff indoors. with the windows closed (usually only at night), i put the air purifiers on medium/high.
- 5y ago
- gruez 5y agoDoes the Senseair S8 actually measure co2, or is it inferred via VOC levels?
- simondotau 5y agoI don't know the answer to that specific question, but I do know it's an NDIR sensor. The Wikipedia page on that sensor type likely answers your question— https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor https://en.wikipedia.org/wiki/Nondispersive_infrared_sensor
- MattGaiser 5y agoI am interested. Do you ship to Canada (happy to pay the difference/wait for you to figure out the postage rate)?
- mikefallen 5y agoAlso in Canada and interested in getting some PCBs. Not sure if OP is selling if not i would be into splitting the cost of getting a batch made if its economical
- dasb 5y agoI too am interested but I'm from Chile. (replying to you to not pollute parent level replies)
- ahaucnx 5y agoPlease send me a message through the orange contact button on the webpage.
- ahaucnx 5y agoYes, we will ship worldwide. Please send me a message from our website and the number of PCBs you would like to get and I will check the postage.
- simondotau 5y agoThat's a great resource, thank you. As a tinkerer who is already quite far down the ESP8266 rabbit hole, are you able to tell me if your software distribution has any particular "special sauce" around the interpretation of the data from these sensors? Or is it predominantly glue between the sensors and the OLED display / your cloud service? I am interested in replicating your hardware stack but implementing the software stack using the esphome framework which supports all of the components used in your DIY solution. https://esphome.io/components/sensor/senseair.html https://esphome.io/components/sensor/senseair.html https://esphome.io/components/sensor/pmsx003.html https://esphome.io/components/sensor/pmsx003.html https://esphome.io/components/sensor/sht3xd.html https://esphome.io/components/sensor/sht3xd.html https://esphome.io/components/display/ssd1306.html https://esphome.io/components/display/ssd1306.html
- ahaucnx 5y agoThere is no secret sauce needed. The Plantower sensors tell you the PM2.5 in micrograms directly and we just display it to the OLED display or send it to a server. It is all open source so you can check the code.
- simondotau 5y agoThanks.
- amatecha 5y agoI'm definitely interested to build one of these. Located in Vancouver Canada. Maybe you can mention in a reply to your own post how people can contact you (if you can't still edit your post)?
- kusha 5y agoI am extremely interested. Willing to pay you the cost of the PCBs too.
- deleted 5y ago[deleted]
- colechristensen 5y agoI have an AirVisual Pro, which is quite expensive, but my half finished air quality monitor project had been on the bench for much too long. I have windows open all the time, air conditioning on too often, and dehumidifiers and HEPA filters as well. It is not efficient or particularly environmentally friendly... but I want a CO2 level < 800 ppm and a PM2.5 level under 10... so here we are. My next half baked idea is figuring out a way to have a sealed home and an appliance (or messy bench-top device) to remove CO2 from the room continuously and exhale outside -- current ideas revolve around using a carbonate (lithium? sodium?) in water in an electrolysis cell and an aquarium bubbler to collect CO2 and expel it outside. The best I've been able to accomplish so far is baking CO2 out of baking soda (sodium bicarbonate) and sealing it in about a cubic foot container and achieving ~300 ppm CO2 (lower than outside which is ~400-450).
- fifteenforty 5y agoYou are describing an anaesthesia circle breathing system, otherwise known as a rebreather scuba set. :-) You would need to consider the occupant oxygen consumption. A typical human respiratory quotient is 0.8 (0.8 mole of CO2 produced for every 1 mole of O2 consumed). You’ll get a net inward movement of gas into house all things being considered. Anyway, don’t do if. If you do it ‘right’ the argon will slowly build up and you’ll asphyxiate. Thankfully achieving that level of seal is very difficult. If you are really worried about PM2.5, just wear a PAPR.
- colechristensen 5y agoOh I'm not interested in hermetically sealing my apartment, there are no worries of normally constructed buildings being able to withstand a meaningful difference in oxygen pressure between inside and outside. CO2 pressure though can easily be increased by a large factor (5x is easy) and maintained with humans inside and closed doors and windows. PM2.5 is easy to maintain with HEPA filters. CO2 is not easy to maintain without forced ventilation, and really I would like to try inside levels lower than outside levels. (say 300 ppm)
- 5y ago
- ahaucnx 5y agoThank you for all of you interested in getting the PCBs. To send me a message please go to https://www.airgradient.com/diy/ https://www.airgradient.com/diy/ and send me a message with the orange chat button. Thanks!
- ac29 5y agoThere was a bit of interest last time I remember you posting on here as well - have you thought about putting up a batch on something like crowd supply? I think it would sell well enough to make it worth your time, and fire season is coming up again soon.
- ahaucnx 5y agoYes that might be a good idea but I am very happy that so many people are interested in building one and that we can increase the awareness on air quality so I am happy to do the work ;)
- roflc0ptic 5y agoYeah, this is an interesting enough problem to me that I recently started researching how to build an arduino version of what this person is offering - in my head, I basically reinvented the product they're offering, without all of the nasty bits of actually having any idea how it works. I would definitely pay a reasonable amount of money for a set of sensors that Just Worked that would collect data in my house.
- markasoftware 5y agoI see the aliexpress link to the PM sensor doesn't work (at least not in the US); where else do you recommend buying one?
- OBFUSCATED 5y agojust fyi, the contact us for details button is not working for me. 4(index):14 Uncaught ReferenceError: zE is not defined at openWidget ((index):14) at HTMLDivElement.onclick ((index):308)
- krysp 5y agoI'd be very interested in this, please email me your PayPal!
- benhurmarcel 5y agoCan it be powered by a battery, to be portable?
- ahaucnx 5y agoYou can just power it with the USB cable from a power bank.
- pred_ 5y agoI understand how fixing leakages, or more generally, not properly ventilating your place, would increase CO₂ levels, but where do air purifiers come into the picture? Is it just because someone who has an air purifier is also more likely to not ventilate (to keep PM2.5 down?), or are air purifiers themselves somehow bad for CO₂ levels? I can't guess why they would be, and searching around a bit doesn't seem to suggest that's the case either.