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Important tip: if you set up an air purifier in your home, make sure to plug all drafts around your house: windows, doors, etc. Even a DIY purifier with small a

Important tip: if you set up an air purifier in your home, make sure to plug all drafts around your house: windows, doors, etc. Even a DIY purifier with small airflow can make your indoor air excellent if given enough time to do so and no leaks to fight against. If you want to get some fresh air in your home, do not leave a window half-open all day long—instead, open all your windows at once to cycle the air as fast as possible, then close them again and let the purifier do its job. If you do that in the morning (ideally just before leaving, if you aren't staying home), you'll have great air quality through the entire evening and night. Since we're on HN, I'll also mention a toy project I built a while back [0]. It uses a Raspberry Pi to read particulate matter sensor mesurements over serial link from a Dylos 1100 Pro, then pipes it into Redis and InfluxDB and ultimately Grafana for presentation. I've used it to track the air quality in my home in for the past year or so and it's pretty fun. In my case, cooking is usually the biggest contributor to poor indoor air quality! [0] https://github.com/peferron/air-quality https://github.com/peferron/air-quality

hinkley 8y ago
Also open your windows when you vaccuum. Send most of the dust outside instead of just what gets caught in the filter.
lappet 8y ago
This is great! Thanks for sharing :)
heybrendan 8y ago
Very interesting! How does the Dylos 1100 Pro compare to, for example, the Nova SDS011 sensor? By my cursory review, the SDS011 is much cheaper and appears to offer a more native Raspberry Pi-compatibility experience. Is the Dylos more precise? Can it produce readings the SDS011 can't? Are the two sensors measuring fundamentally different things? Finally, if you had to do it all over again, would you choose a different sensor or stick with the Dylos? Thanks for sharing your project and for your insights!
- peferron 8y ago
  I bought the Dylos almost 5 years ago. At that time I don't think the SDS011 was available. A cool feature of the Dylos is monitor mode. It wakes up every hour, spins the fans for 1 minute, and spits out a measurement. It's convenient for 24/7 monitoring because it reduces fan noise and dust accumulation. I don't know if the SDS011 offers something similar, or if you could somehow program that yourself, but that may be something to consider. I'm very happy with the Dylos overall. In addition to being 5 years old, mine has been running in monitor mode for the past year and a half with no issues so far so I really can't complain about reliability. Issues are size, fan noise, antiquated UI, and also antiquated connectivity, although I personally enjoyed working with serial (threw me back to early Duke Nukem LANs before we moved to IPX). I wouldn't be surprised if there are superior alternatives today, at least regarding usability.
  - misev 8y ago
    The SDS011 with firmware from luftdaten.info seems to work in this mode by default: sensor is turned on for 20 seconds for measurement at every 150 seconds interval. This should be tunable though. The theoretical lifetime is 8000 hrs of continuous operation, so they estimate 6-7 years longevity in this default mode.
- misev 8y ago
  SDS011 is the basis for luftdaten.info; have a look here for a diy guide (optionally including humidity/temperature as well): https://luftdaten.info/en/construction-manual/ https://luftdaten.info/en/construction-manual/
  - imarg 8y ago
    Hi, this is an interesting project. It seems to be targeted for outdoor measurements. Do you know if this also suitable for indoor measurements (meaning if you want something for indoor air quality, would you measure the same things?) I recently watched a video from dhh (https://youtu.be/MRqh8oLY7Ik https://youtu.be/MRqh8oLY7Ik) about air quality at home and was thinking if there was a nice diy solution for measuring it.
ramenmeal 8y ago
Could you explain? I'm curious why it'd be better to have the air filter going rather than having good airflow from outside via open doors and windows? Are we trying to filter dust/ things produced in the house, or pollutants from things outside the house?
- peferron 8y ago
  Yeah, sorry, just assumed that pollutants were coming from outside. I'm just so used to it after living several years in China and now being affected by California wildfires. If the outside air is better than inside, then yeah you probably should air out your home as much as possible unless it's unbearably hot or cold outside :)
  - z3t4 8y ago
    You could also put the filter on the air intake.
- deleted 8y ago
  [deleted]
joncrocks 8y ago
Of course you may also want to be careful doing this, as unless there is a certain amount of airflow/ventilation you may start having other issues, such as a build up of CO2.
amelius 8y ago
How do you know you are measuring bad particles, and not good particles (like salts if you live nearby the sea)?
- brixon 8y ago
  Why would you want to keep salt in the air? It will promote rusting.
  - amelius 8y ago
    The question was more about whether the measurement tool provides useful feedback in case of "salty" air. Filtering is a lot of work, and might not be necessary.
  - ajuc 8y ago
    It's healthy apparently. I've been to a health resort in Ciechocinek where they have huge wooden construction through which they flow salted water so it evaporates and makes the air better for people there. It's called "tężnia", have no idea how to translate that :) Google gives "graduation tower" but I doubt it's correct. https://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Ciechocinek1.jpg/1920px-Ciechocinek1.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Ci...
ungzd 8y ago
Some data about effectiveness of air purifiers when leaving windows open: https://smartairfilters.com/en/blog/purifiers-useless-windows-opened/ https://smartairfilters.com/en/blog/purifiers-useless-window...
gdubs 8y ago
I had an energy audit done recently and they said that 50% of the air in most homes comes up from the crawl space (due to the Stack Effect).
rsync 8y ago
"If you want to get some fresh air in your home, do not leave a window half-open all day long—instead, open all your windows at once to cycle the air as fast as possible, then close them again and let the purifier do its job. If you do that in the morning (ideally just before leaving, if you aren't staying home), you'll have great air quality through the entire evening and night." Why not have a filtered air ingress ? That is, instead of sealing the house, why not install an air purifier in a window and have constant fresh air inflow ?
- LeoPanthera 8y ago
  Most filters and purifiers rely on the air being recycled through the filter multiple times. They only remove some known percentage of particles with each pass.

hinkley 8y ago

Also open your windows when you vaccuum. Send most of the dust outside instead of just what gets caught in the filter.

lappet 8y ago

This is great! Thanks for sharing :)

heybrendan 8y ago

Very interesting! How does the Dylos 1100 Pro compare to, for example, the Nova SDS011 sensor? By my cursory review, the SDS011 is much cheaper and appears to offer a more native Raspberry Pi-compatibility experience. Is the Dylos more precise? Can it produce readings the SDS011 can't? Are the two sensors measuring fundamentally different things? Finally, if you had to do it all over again, would you choose a different sensor or stick with the Dylos? Thanks for sharing your project and for your insights!

peferron 8y ago
I bought the Dylos almost 5 years ago. At that time I don't think the SDS011 was available. A cool feature of the Dylos is monitor mode. It wakes up every hour, spins the fans for 1 minute, and spits out a measurement. It's convenient for 24/7 monitoring because it reduces fan noise and dust accumulation. I don't know if the SDS011 offers something similar, or if you could somehow program that yourself, but that may be something to consider. I'm very happy with the Dylos overall. In addition to being 5 years old, mine has been running in monitor mode for the past year and a half with no issues so far so I really can't complain about reliability. Issues are size, fan noise, antiquated UI, and also antiquated connectivity, although I personally enjoyed working with serial (threw me back to early Duke Nukem LANs before we moved to IPX). I wouldn't be surprised if there are superior alternatives today, at least regarding usability.
- misev 8y ago
  The SDS011 with firmware from luftdaten.info seems to work in this mode by default: sensor is turned on for 20 seconds for measurement at every 150 seconds interval. This should be tunable though. The theoretical lifetime is 8000 hrs of continuous operation, so they estimate 6-7 years longevity in this default mode.
misev 8y ago
SDS011 is the basis for luftdaten.info; have a look here for a diy guide (optionally including humidity/temperature as well): https://luftdaten.info/en/construction-manual/ https://luftdaten.info/en/construction-manual/
- imarg 8y ago
  Hi, this is an interesting project. It seems to be targeted for outdoor measurements. Do you know if this also suitable for indoor measurements (meaning if you want something for indoor air quality, would you measure the same things?) I recently watched a video from dhh (https://youtu.be/MRqh8oLY7Ik https://youtu.be/MRqh8oLY7Ik) about air quality at home and was thinking if there was a nice diy solution for measuring it.

ramenmeal 8y ago

Could you explain? I'm curious why it'd be better to have the air filter going rather than having good airflow from outside via open doors and windows? Are we trying to filter dust/ things produced in the house, or pollutants from things outside the house?

peferron 8y ago
Yeah, sorry, just assumed that pollutants were coming from outside. I'm just so used to it after living several years in China and now being affected by California wildfires. If the outside air is better than inside, then yeah you probably should air out your home as much as possible unless it's unbearably hot or cold outside :)
- z3t4 8y ago
  You could also put the filter on the air intake.
deleted 8y ago
[deleted]

joncrocks 8y ago

Of course you may also want to be careful doing this, as unless there is a certain amount of airflow/ventilation you may start having other issues, such as a build up of CO2.

amelius 8y ago

How do you know you are measuring bad particles, and not good particles (like salts if you live nearby the sea)?

brixon 8y ago
Why would you want to keep salt in the air? It will promote rusting.
- amelius 8y ago
  The question was more about whether the measurement tool provides useful feedback in case of "salty" air. Filtering is a lot of work, and might not be necessary.
- ajuc 8y ago
  It's healthy apparently. I've been to a health resort in Ciechocinek where they have huge wooden construction through which they flow salted water so it evaporates and makes the air better for people there. It's called "tężnia", have no idea how to translate that :) Google gives "graduation tower" but I doubt it's correct. https://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Ciechocinek1.jpg/1920px-Ciechocinek1.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Ci...

ungzd 8y ago

Some data about effectiveness of air purifiers when leaving windows open: https://smartairfilters.com/en/blog/purifiers-useless-windows-opened/ https://smartairfilters.com/en/blog/purifiers-useless-window...

gdubs 8y ago

I had an energy audit done recently and they said that 50% of the air in most homes comes up from the crawl space (due to the Stack Effect).

rsync 8y ago

"If you want to get some fresh air in your home, do not leave a window half-open all day long—instead, open all your windows at once to cycle the air as fast as possible, then close them again and let the purifier do its job. If you do that in the morning (ideally just before leaving, if you aren't staying home), you'll have great air quality through the entire evening and night." Why not have a filtered air ingress ? That is, instead of sealing the house, why not install an air purifier in a window and have constant fresh air inflow ?

LeoPanthera 8y ago
Most filters and purifiers rely on the air being recycled through the filter multiple times. They only remove some known percentage of particles with each pass.