# Questions For Dylos DC1100 Pro air quality monitor users



## Joel_B (Aug 14, 2014)

Just got mine today.
Measurements I made:

Bedroom 500 35
Garage 1350 225

Clearly there is more dust floating around in the garage (my workshop).
At what level do you consider it a hazard?

If I convert 1350 - 225 to mg/m3 it comes out to about 0.01

These still seems very low when I read about limits of 1mg/m3 for wood dust which would be a Dylos reading of 100,000

Edit:

I discovered the chart on the back:

3000+ = Very Poor
1050 - 3000 = Poor
300-1050 = Fair
150 - 300 = Good
75 - 150 = Very Good
0 - 75 = Excellent

So the air in my house is Fair and the garage with no activity is Poor.

I wonder why these numbers don't seem to correlate with the mg/m3 numbers.


----------



## Joel_B (Aug 14, 2014)

Something very strange happened. The indoor readings suddenly jumped from 400 to 4,000.
I checked the garage and its still where it was before.
We do have central forced air heating and the filter doesn't fit very well on the furnace, that's the only thing I can think that would cause it to go up.


----------



## Joel_B (Aug 14, 2014)

I let it run overnight in monitor mode (checks the level every hour) and the level declined with each hour.
I suspect because the thermostat is set to 62 at night so the furnace doesn't run as much.
So I think there is a problem with dust in the ducts or somehow getting into the furnace from the garage.


----------



## HarveyM (Nov 11, 2012)

Have you checked the woodgears site? Matthias has an article on the Dylos. He notes that cooking, etc. can dramatically increase your readings. Also when was the last time you inspected/changed your furnace filter? I've started changing mine every 3 months as per the recommendations of our HVAC tech.


----------



## Joel_B (Aug 14, 2014)

I am having the furnace inspected on Monday. I recently changed the filter but the furnace is about 30 years old and does not really have a good may to mount the filter, it just sits on top of a rectangular hole and I tape it down in places with aluminum tape. I am going ask them if there is a way to mount the filter so it is airtight. Also we have some pet rabbits in the house and there is always hay sitting out. This morning I opened the hay box and rustled it up and reading doubled but it wasn't super high.


----------



## AZWoody (Jan 18, 2015)

Read some articles on home filtration.
Other than the furnace, windows and doors let a large amount of dust in. If you have carpet, that is a dust trap as well.

The furnace can be cleaned and set with a good filter but it only circulates the particulates already in the house. It doesn't introduce any unless there is some kind of leak of it's outside.


----------



## Joel_B (Aug 14, 2014)

I spoke with somebody at Dylos and they were very helpful.
He said anything below 1200 isn't so bad and 400 is easily done inside. Below that takes good filters.
I asked him about the OSHA limit of 1mg/m3 which seems huge compared to the Dylos reading and he said that limit is a joke and is set to make it easy for anybody to pass.
I had a "Vornado" air cleaner stored in the garage that we have not used for a long time.
I ran it in the bedroom with the doors closed for awhile and the small particle count did not go down but the large particle count went down some. It uses cheap pleated cardboard filters and they don't have any rating on them. I guess I need a true HEPA filter to really do any good. I am really glad I got the Dylos its a real eye opener and reality check. I feel a lot more confident I will be living and working in safe environment. We only have carpet in our living room (needs replacing) everywhere else is tile or wood.


----------



## gtbuzz (Sep 19, 2011)

How are you doing the conversion from particle count to mg/ml. I could be missing something, but I don't think it's possible.

The numbers provided by the DC1100 are a running tally of count vs time. Its counting the number of particles going past its sensor over the last 10 seconds and I haven't been able to find a spec for sensor size either so based on that I'm not sure what unit volume the particle count is relative too. Even if you knew that though, you'd still only have volume data and you'd need to know the mass of the particle to get to a mass / volume measurement. Having said all that, I could be wrong.

I've always just gone by the chart on the back, as it's really a qualitative measurement anyway. As long as it's below 500 ish it seems good to me. I've found that the small particle numbers can really be affected by just walking around, especially if your workspace isn't actually clean but rather the dust settled. If I leave my garage and run the air cleaner for an hour or so, the small particle numbers can get down below 100. Can actually tell a difference in the way the air smells. While I'm actively doing work, however, it seems difficult to keep that number below 1000.

Ultimately what that tells me is I ought to be wearing a respirator during the bulk of my dust-producing operations. I've recently gotten into the habit of always wearing a respirator at the lathe, including during roughing, and I can honestly say that I feel a lot better afterwards.


----------



## Joel_B (Aug 14, 2014)

The conversion simply to subtract the large particle count from the small particle count and divide by 100,000.
See more here:

http://billpentz.com/woodworking/cyclone/dylos.cfm

But what you said is I think about right. I just got a 3M 7500 respirator and plan to wear it full time in the shop.


----------

