The Dylos does a good job of measuring the particulate matter in the air at a given moment. It does NOT do what it claims in this sentence from the product description: "Multiple modes including minute, hour, day and monitor to evaluate your air quality and store up to 30 days of air quality history for review." THIS STATEMENT IS FALSE. If you select the "minute" report from the menu, it reports the last sixty minutes, not a second more. If you select the "hour" report on the menu, you get the last 24 hours, not a minute more. If you select the "day" setting you get one reading from 24 hours ago.
If you select "month," you get one reading from exactly 30 days before, and nothing more. I expected to let it run for several days in a row and then write down the data, hour by hour, for review. THE DC1100 Pro WiLL NOT DO THIS. In other words, it may well "monitor" the air each "minute, hour, day . . . up to 30 days," but there is no way for you to "evaluate" the data for two days, much less 30, because you cannot get at the data. The only way to assess what's happening in your environment hour by hour is to stop and record it every single day. I'm not in a position to do that, so it's frustrating and useless to me. Nowhere in the meager documentation is this limitation mentioned, and it should have been. I sent it back. Thanks Amazon for your return policy.

I have many mixed feelings about this device. It came out 10 years ago, and frankly I expected it would have evolved more, but it hasn't. You open the box and it comes with a wall wart. Not the kind that they have been shipping with products for the last 10 years, but rather those heavy analog transformer model. For $260 they couldn't have worked out a deal on a more energy efficient transformer?

So you turn it on and there are two numbers displayed and this bar that seems to bounce every second or two. There are no markings to even tell you what these numbers are, you have to open the instruction to answer the mystery. Would it to have killed them to label the numbers? The bar represents pollution level, I guess, but it sure would have been nice to average counts over a minute or two instead of a bouncing bar which means nothing.

So the two numbers displayed are the common PM2.5 or PM10 or AQI right? Nope, they are NONE of these. They are a particle concentration amount that can't be compared to any common measure used today. So it can convert to other common measure, right? NOPE. Read the web and you can find 200 different ways to convert these numbers, but all these formulas all yield widely different results. Couldn't the company add that feature? They had 10 years? NOPE.

And then there is the user interface that provides very little information but makes it hard to get at easily. Even going from "Monitor mode" to "Continuous Mode" is certainly harder than it should be.

So does it work? The numbers seem to increase with more particles in the air, but without any standard measure, nobody has any idea of the accuracy of this thing, and I'm sure the manufacturer likes it that way.

So in the end, a frustrating device that could have been improved greatly by the manufacturer if they only cared to. They didn't.

I should also add, on the back of the device is a sticker stating which particle counts are good, bad, very poor air, etc. based on the small count (larger number) reading. Basically it gives some counts and says, for example, 1050 - 3000 is poor. Sounds reasonable. But at other times the company has said you can take (small particle - large particle)/100 to get an estimate for PM2.5. So lets look at that, lets say small particle in 2000, right in the middle of the "poor" range. Lets say large particles is zero for the sake of argument. So 2000-0 = 2000 then divide by 100 gives you 20. So they are saying the PM2.5 value would be 20. But if you investigate, a PM2.5 of 20 is very good air, not poor. So you have lots of disjointed information, and maybe even 2 stars for this thing is generous.

I use this in my wood shop to ascertain the quality of the air and how well any particular dust collection effort is doing. It is amazing to me how much commentary there is about wood-shop dust collection methods when you have nothing more sophisticated that your human nose and eyes. It really make most reviews of dust collection equipment and technique somewhat useless. As most woodworkers have come to appreciate, it is the dust that you can't see that will kill you. This little gadget is the key to doing more than seeing and smelling dust in the air. It can detect faithfully what you cannot, and I have come to rely on it and I find myself glancing at it many times a day when working in the shop.

This monitor,Dylos DC1100 Pro Air Quality Monitor, is saving me a lot of money, because now I know when to run my air purifiers and what setting to use. Much better than worrying and running them on high all the time. I have two of them and am thinking of getting a third. I use the "monitor mode" during the night and "continuous mode" during the day.

Bought this machine because of the reviews and knew some of its limitations beforehand (from other air quality blogs/sites).

A couple of key things to be aware of:
- Measures all types of particles, including water particles. Taking a shower, boiling water, cooking, etc will all raise the particle count.
- Not a VOC gas detector (like some others on the market. Ideally an integrated particle counter with a VOC gas detector would be ideal)
- No smart app or any way to download the data (unless you shell out much more money for a very legacy PC interface)
- Cabled. Means measuring around ur house requires constant plugging/unplugging or a really long extension cord.
- The unit doesn't support 220-240V in case you live outside of the US.

Biggest flaws:
- A small hard-wired computer fan drives the whole unit. If the fan stops working for whatever reason (as is my case after 1.5 years), you're left with an unusual machine.
- I question whether a cheap computer fan runs consistently/reliably enough to be even be used for this application. I'm not convinced these fans are spec'd tight enough to deliver a reliably similar airflow (ie. owners of the same model unit comparing readings) and especially over time. If the fan spins slower, it'll move less air through the unit and invariably affect the reading. The unit has no way to adjust fan RPM and a lookup of the OEM fan manufacturer doesn't indicate any capability for the fan to lock a sepecific RPM. If you received a unit with a defective/slower fan, you'll just think your air is cleaner than it actually is.
- The readings are arbitrary and do not reflect any kind of standard measure. There are numerous posts online where folks have tried to figure out and convert the readings to API/AQI, but shouldn't this just be worked in? Also, see point above on data inconsistency - maybe they couldn't pin down consistent airflow across units making it difficult to apply a standard conversion logic?

In light of all of this, the most frustrating part is how unreliable the device is. This would explain why they only provide a 90-day warranty! My machine's fan started making noises upon startup/shutdown after 8 months, and by 18 months, it fan finally stopped working altogether. I emailed support, and they replied back saying I need to ship it back to them (at my expense), I need to pay for repair costs (approx $45) and pay for shipping back to me. No offer to send me a replacement fan, and I can see why (with the poor design of a hardwired fan). How much harder to include a plug in fan (like every other computer fan)?

Guess I'm stuck with sourcing my own fan, and soddering it back onto the board myself.

On the bright side, I can confirm that (when it does work), it does report particles which goes up and down based on the environment, and also provides near real time feedback. The interval sampling mode (when it works) is also quite useful so the fan doesn't have to run 24/7 (which I'm pretty sure it's not spec'd for).