Particle counters?

[Simon Magennis]

I find that dust is bothering more than in the past. I do take precautions but I don't have anything to measure the effects (apart from my lungs ).

I did a few searches this morning and found a range of counters and air quality meters. Prices from about $20 to $7000+. All seem to work with a laser to calculate the particulates. From the descriptions there are two things that push up the prices: size measured - the pricey ones start at 0.3 whatever the unit is, to 25 while the cheaper ones do 1,2.5 and 10. The single biggest price booster is calibration against a known standard (iso/nist). The $500 range upwards tend to give an accuracy number although these are uncalibrated. +/-15% for 2.5 particles is one I noticed.

I am looking more at the $20 to $200 units than the 3.5k-7.0k range.

What have you got?

Do the $20-$50 units do anything except show pretty numbers?
Given the air pollution in china, I suppose it is possible that the real cheap units do actually work to some extent.

Recommendations for or against any units?

Thanks.

Simon

[Bob Gramann]

I have the Dylos DC-1100 Pro. It does .5 micron particles. When the count gets up, I put on a mask and turn on the air filter. I’m not sure you need exceptional accuracy (how would you calibrate?). But, you do need to know when there’s enough dust in the air to harm you. The count shows particles per .01 cubic foot, so multiply by 100 and you have the count per cubic foot. When I got it, it showed 700 in the living room with the grandchildren playing on the rug. I figured that was the upper limit and now put on a mask and start the filter in the shop when the count hits 300 (30,000/cu ft). It also shows a 2.5 micron count, but that size is supposedly not as dangerous, so I use the smaller particle count as my indicator. I consider my purchase to have been well worth the money. I’ve had it for 6 years and would buy another if it died.

[Simon Magennis]

Thanks Bob.

[David King]

I just got an inexpensive unit from an outfit called Temtop that measures PM2.5 and PM10 plus humidity and temperature in Centigrade. It was $60 postage paid and came in a couple of days from California. https://temtopus.com/products/temtop-lk ... y-detector I was curious as to why the State run AQI station a couple of blocks from my house was consistently reading 250-400 and I was getting PM2.5 reading in the 800 range on my unit. It turns out AQI and PM2.5 are different things. It's an impressive piece of engineering at that price and I was happy to see that my main dust collector is not making my shop air worse. I chose based on wirecutter reviews from the NYTimes. I can't say I wouldn't have preferred owning a Dylos unit but for the price this is certainly telling me what I needed to know. I can say that the combination with a Blueair air purifier was very rewarding during the recent wildfire events. I had installed a MERV 14 filter in my furnace blower which could only drop the PM2.5 down to about 90 in the house (it had been as high as 440 before I hacked the blower relay to stay on 24-7). The Blueair which is a HEPA + activated charcoal filter dropped the PM2.5 to around 30 in a half hour.

[Barry Daniels]

In my training as an indoor air specialist we were taught that the particle size that is most dangerous is the sub micron particles. The reason for this is they are small enough to stay airborne almost continuously due to normal air movement and currents in an inhabited building. They are also small enough to get into your alveoli.

[David King]

Barry, Thanks for chiming in here, so in essence .01 or .03 are what we need to measure? I wonder why PM2.5 became the de facto reference?
I take it that once particles get lodged in the alveoli they won't ever come out and can then cause all kinds of trouble in time.

[Barry Daniels]

Yes alveoli do not clear out particles. Only your bronchial tubes have cilia that will clear particles.

The 2.5 standard was probably chosen because it is easier to measure and was at least some level of protection. Lowering the standard into the sub micron zone would be a lot more expensive and require a lot better filtration that what industry is willing to spend. However, if these costs were balanced against what people spend on medical costs to treat lung disease, it would probably be worth while in the long run. Safety and environmental costs usually are easily paid for when you look at the whole picture.

[Carl Dickinson]

Barry, what counter would you recommend? I'm about ready to get a Dylos. I need one for the shop and the smoke around here lately has been baaad!

[Barry Daniels]

Carl, I am not knowledgeable about particle counters. I only rented one once and it turned out to be unusable for what I wanted to do. We did our indoor air quality evaluations with other methods and tools. However, I have read good comments on the Dylos.

[David King]

See if you can find a used Dylos to track down your sources once and remedy them but better yet spend that money of better filtration for your whole house. Lennox has a pretty impressive unit that's HEPA rated and comes with other bells and whistles including a UVA light that activates some catalyst thing to kill off mold spores or someat. The filter media is 5" deep and won't fit anyone else's filter frames so you have to spring for the whole unit via your Lennox dealer.

[Simon Magennis]

European houses don't have forced air systems like the USA. So this is not an option.

There is no ducting in any houses except the latest and greatest "zero energy" houses which are completely sealed and must have a forced system.

In most of Spain, where I now live, you are surprised if there is any heating except for plug in electric radiators. Probably different in the few mountain areas.

[Steve Sawyer]

Hey all - just noticed this old thread when getting ready to post something in this section. I too have a Dylos particle counter. The thing I can add to this discussion is that my shop is, much of the time, cleaner than the rest of the house. We don't have a forced-air heating system (hydronic/baseboard heating) so that really surprised me. The other point is that I have an old Jet ambient air cleaner. It's not manufactured anymore, but Rikon has a similar small-footprint unit that I'd switch to in a heartbeat if mine ever died. It has a washable furnace filter backed up by a sub-micron pleated filter element, and it's astounding what a good job this does. I have a full 3hp Oneida system to all the stationary power tools, and a Festool shop-vac "permanently" attached via blast-gates to the spindle sander, SCMS and drill press. There are still operations (particularly with MDF) that will spew dust into the air, and of course routers are notoriously difficult to source-capture the dust. There is also the endless hand-work using rasps, hand-sanding, planing etc. that all get fine dust into the air. The ambient air cleaner will bring the particle count from shockingly high levels of 2000 or more down to 300-400 in about 10 minutes in my ~500 sq ft. shop.

The thing I like about the Dylos is I never have to guess at how effective my efforts at dust control are, and allows me to immediately take remedial efforts like putting on a mask or firing up the ambient air cleaner.