View Full Version : indoor air quality

11-19-2012, 06:01 PM
For some reason, while trying to get to sleep last night I started to think about how to measure indoor air quality. Things that were going through my mind- propane is heavier than air and will collect in low areas, radon infusion, use of co2 in the shop, welding/brazing/soldering processes-

We used to use dry ice for fog effect in concerts, and at the time I didn't pay any attention to the fact that it will displace oxygen-bearing air. Here's a building full of people marvelling at the effects, with no regard to whether it will affect the air they're breathing- admittedly there's a large area with ventilation fans running constantly, etc, and nobody ever died from lack of oxygen, so it was a non-issue.

My question though concerns the closed-in home basement shop. How could one go about actually checking the air quality? Is there an affordable device or something which could be made that would give an indication of the contents of the air?

I suppose the best answer is to ventilate sufficiently and maintain any air circulation systems and fresh air intakes- my own 'system' as it were has a floor-level 'scoop' with a fan to exhaust floor-level air. That does make a difference to the subjective air quality, but of course I have to remember to operate it now and then. It might be good to have a detector though- something which might alert to the presence of unwanted gasses and low oxygen levels.

11-19-2012, 07:05 PM
Depending upon how you define "affordable" there are many places that sell monitoring devices. Ones that measure CO2 levels are very common and cheap. Radon needs to be done with a test kit and sent to a lab for results. Meters for other gases are available. I used LabSafety.com but looks like they got bought by Grainger.


11-19-2012, 08:18 PM



11-19-2012, 08:22 PM
If you're doing something that affects air quality, you should ventilate, period. Brazing, welding, for sure. Even using cutting fluid on the lathe, at least if it smokes.

I was parting off some 1 1/4" SS the other day, and the cutting oil (Pipe threading fluid) was smoking terribly, to the point of making it impossible to even breathe. Grabbed a 4" computer fan, put a screw through the corner, plugged it into the TS chuck, and clipped on the ol' suicide cord. That blew the smoke away from me so I could breathe. Opened the door for a while to rid the shop of smoke.

Yes, the furnace will run a bit more, so be it.

11-19-2012, 09:24 PM
Looks like the best thing I can do, without measuring anything, is to put my floor level exhaust fan on a timer, and possibly run a fresh air intake fan at the same time. That would probably mean cool to cold air coming in, but would help prevent exhaust from the furnace from spilling over into the room when the exhaust fan is running. Yes, the furnace would run a bit more.

My fresh air intake is at ceiling height in the basement, which puts it about three feet above ground. It's basically there for the furnace, but the fact that cold air coming in mixes with the highest air in the basement means that it shouldn't create a non-tolerable cold zone when the fan is running. The furnace has its own exhaust fan, which must prove it's running before the gas valve opens, so even if I create some negative pressure in the building, it shouldn't become a problem for the furnace. Worst case, the airflow sensor on the furnace exhaust stack would register not enough flow, and the furnace simply won't come on.

The question I started with was about how to sense bad air quality, basically. I do have a nose, but one tends to get used to the smells in your own place. If it's bad and happens fairly quickly, you'd notice it, but otherwise you could be living in less than healthy air. It might be good in a lot of buildings to be able to 'read' the air and see a breakdown of the components. It's fine of course to have a monoxide detector and a smoke detector, etc, but this could be something for a user to get a little interactive with. Of course, in a lot of situations there's the problem of where are you going to get cleaner air-

11-20-2012, 01:06 AM
Electrostatic filters work fairly well,the better ones even handle odors and VOC's-


11-20-2012, 01:44 AM
Although one can purchase air quality monitors that detect various gaseous pollutants, one usually knows when the activity that he is engaged in is bad for one's health.
It doesn't take too many canary's in the shop dropping off of their pedestals to realize that many of the activities we engage in are not good for living things.

During the warmer months proper ventilation is easy and cheap, hell it's done without thought.
It's not just gaseous pollutants either, don't forget about the microscopic particulate matter floating in the air. I was just reminded about this the other day while cleaning some of my light fixtures...yuck!

WS's link to the electrostatic air cleaner is a good thought.
Also in the realm of good clean warm air is a local link for you that can give you fresh, clean, (and most important for the colder climes), warm air.
A recirculating heat recovery air exchanger (http://www.homehardware.ca/en/rec/index.htm/Heating-Ventilation-Cooling-Home-Comfort/Ventilation/Venting/Air-Exchangers-Acc/Recirculating-Heat-Recovery-Air-Exchanger/_/N-ntinb/R-I2670204).

Clean air won't be cheap but then neither is a set of lungs.

Personally I just open two bay doors for a couple of moments, grab a hot coffee and a smoke, then head back into the shop.http://i76.photobucket.com/albums/j31/250willy/cee48e43.jpg