Detecting Dirty Air

[ano]

I have just installed an automated system to bring in outside fresh air into my house, so i can get some cool air at night to save my cooling costs and to better ventelate my house. But, of course for each solution there is a new problem. :angry2: When there are wildfires and smoke around, or when its windy and dusty, I don't want to bring in outside air.  I have an air filter, but that keep out really bad air.
 
So, my question, has anyone seen a sensor of any type that can tell me if the air is clean or full of particles?  Hopefully not too expensive.  That way it would shut the dampers and no bad air.  I know, easier said than done.

 

[electron]

This is a great question, would love to do something similar.  I don't think there is going to be a cheap AND effective way of doing this, but I really want to be proven wrong.

 

[naething]

Maybe you don't have to detect it... just poll the air quality from an external source?
 
For example: http://airnow.gov/ (run by the EPA)

 

[ano]

Maybe you don't have to detect it... just poll the air quality from an external source?
 
For example: http://airnow.gov/ (run by the EPA)

While that is a very good idea, and CQC could do that potentially for me, I was more thinking something I could connect to the Omni which I try to keep my most important functions on.
 
Also, I'm not sure I need something really advanced. I'd just say smoke and dust, and you can't always get good localized info on that.
 
Lots of people have these fresh air systems so this has to exist somewhere I hope.

 

[damage]

Maybe you don't have to detect it... just poll the air quality from an external source?
 
For example: http://airnow.gov/ (run by the EPA)

 
that's what i'm doing.  i screen scrape it periodically throughout the day and put the particulate matter & ozone levels in my mysql db for scripting & display on our ha guis.

 

[roussell]

Maybe some combination of a hacked smoke detector for the smoke and light/photocell arraingement for dust and other particulates? You have to rig up a sampling station that would continuously flow outside air through it to test but it should work in theory. In fact a cheap smoke detector might even detect both - I remember in years past dust setting off some of our smoke detectors.

As a higher-priced alternative, most data centers have an air quality monitor these days. I can remember what they're called at the moment but I've seen some that are sensitive enough to alert on a person walking in after smoking a cigarette outside the facility.
 
Edit: You also might be able to use one of these: Dylos Air Quality Monitors

Terry

 

[ano]

Sharp makes these for $12:
https://www.sparkfun.com/products/9689
But it may be a bit more DIY than I was hoping for. 

 

[roussell]

There's also the Air Quality Egg...

 

[ano]

They all have the same problem, no Good/Bad relay output.

 

[electron]

We just need to know what type of RF sensor they are using for that egg, and interface it ourselves.  But maybe all it does is measure humidity etc.

 

[Automate]

Base egg only measures NO2 and CO but "You can now upgrade the Air Quality Egg (including the DIY versions) with sensors for O3 ($25), VOC's ($25), radiation ($60), and particulates ($40)!"

 

[tmbrown97]

I'm still a bit manual.  We use a whole house fan often to offset the $900 summer electric bill...  but in northern California, we often have to contend with wildfire smoke - so we open the windows and sniff - if all is OK, kick on the fan!
 
I know - no help... but automation can't solve all problems affordably.  I'm sure I could fix it - but not sure I could afford the fix.

 

[ano]

I'm still a bit manual.  We use a whole house fan often to offset the $900 summer electric bill...  but in northern California, we often have to contend with wildfire smoke - so we open the windows and sniff - if all is OK, kick on the fan!
 
I know - no help... but automation can't solve all problems affordably.  I'm sure I could fix it - but not sure I could afford the fix.

There are laser particle detectors for under $200, and so many people have fresh air systems, I find it hard to beleive this doesn't exist.  In fact since 1999, in Minnesota, all new home construction includes a fresh air system, by law.  It has to exist. Maybe. :unsure:

 

[travisdh]

You will find that many devices that exist work around temperature, humidity etc which i believe the eggs will also do as well. You could test for VOC's in the air however you may find that this is pointless depending on what sort of environment you live in (rural vs urban). But my suggestion would be to look towards particulate sensors first, if you can size the particle (that is find a sensor which has an appropriate particle sensing size) you should find that it detects smoke, dust and the likes which would be your air quality sensor and could be used to determine if outside air should be used, you might move towards other sensors but things like CO are generally not as much use in outdoor environments (unless you live in highly populated areas) since Carbon monoxide should normally be low outside (again depends on your area).
 
So my suggestion in order of priority for air quality testing would be:
 
Particulates
Smoke (separate to particulates)
Carbon Dioxide
Carbon Monoxide
VOC's
 
Most of these can be interfaces with things like Arduino's, sensors like Carbon Dioxide are great inside as they can give you an idea of how 'stale' the air is based on its accumulation, and often in commercial systems these sensors are used as a trigger to determine if the inside air should be supplemented with outside air.

 

[ano]

Yes, around here in Arizona, dust is number one and smoke is number two.  I'm not sure the others really matter that much anyway.