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Thread: Dylos and dust collection

  1. #46
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    OK. So this morning the outside numbers were 3529 and 834. If I'm doing the math correctly, that translates to a PM2.5 of 27. I'm still not sure what the formula is to convert PM2.5 to AQI. What's the correct formula for that?

    I'm used to having small particle concentrations of 500ish and large particles of 15ish at my last home 8 miles inland from here. I've never seen small particle concentrations of 3500 on ambient air.

    You can tell that it takes far longer for my Jet air cleaners to clean the air in my shop, so I don't doubt that the readings are real. I just don't know what has acutely changed over the last few days.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  2. #47
    Quote Originally Posted by Alan Lightstone View Post
    OK. So this morning the outside numbers were 3529 and 834. If I'm doing the math correctly, that translates to a PM2.5 of 27. I'm still not sure what the formula is to convert PM2.5 to AQI. What's the correct formula for that?

    I'm used to having small particle concentrations of 500ish and large particles of 15ish at my last home 8 miles inland from here. I've never seen small particle concentrations of 3500 on ambient air.

    You can tell that it takes far longer for my Jet air cleaners to clean the air in my shop, so I don't doubt that the readings are real. I just don't know what has acutely changed over the last few days.
    Alan, if you check post #24 by David Morse he has links to what I think you’re looking for.

  3. #48
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    Quote Originally Posted by Alan Lightstone View Post
    OK. So this morning the outside numbers were 3529 and 834. If I'm doing the math correctly, that translates to a PM2.5 of 27. I'm still not sure what the formula is to convert PM2.5 to AQI. What's the correct formula for that?

    I'm used to having small particle concentrations of 500ish and large particles of 15ish at my last home 8 miles inland from here. I've never seen small particle concentrations of 3500 on ambient air.

    You can tell that it takes far longer for my Jet air cleaners to clean the air in my shop, so I don't doubt that the readings are real. I just don't know what has acutely changed over the last few days.
    27 is also what I calculate for the Dylos PM2.5 estimate. Mark is correct, I posted a link to the AQI calculation in post # 24. Here it is again. Using that I calculate 82 for the AQI, which is labeled "Moderate".

    I've never lived near an ocean but I can speculate (speculation being so much easier than actual research!). It seems to me that if there's a strong enough breeze for whitecaps to form then some fine droplets of water must be pushed up into the air. The smaller of these could evaporate leaving behind some salt crystals. If you're downwind from this I would bet that these would register on a particle counter.

    Vehicle traffic generates a lot of particulate matter. It comes not only from the engine exhaust but also from rubber wearing from the tires. Are you close to any highways? What's the wind direction relative to those?

    If you have the time and the interest you have a great opportunity to have some fun with this. It looks like you're in a good location with several monitoring stations nearby and enough variation in the particle counts for any correlations you find to be significant. Now I admit that I'm a bit of a data freak so what I find entertaining is certainly not for everyone. I would be recording particle counts, temperature, humidity, wind speed and direction, time of day, and a few more things when I think about it some more. Take several readings a day that include both day and night as well as high and low human activity.

    Do you have the sea breeze/shore breeze cycle? Is there a difference in road traffic weekdays vs weekends? Coal fired power plants nearby? Cement factories? Stone quarries?

    Particle counts are pretty boring where I live. The only time I've seen a really interesting rise in counts was one day last fall when I was downwind from my neighbor's pile of burning leaves.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  4. #49
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    Quote Originally Posted by Mark Daily View Post
    Alan, if you check post #24 by David Morse he has links to what I think you’re looking for.
    Yes, Mark. I did check out that link, but my feeble MIT math educated mind kept missing how to plug the numbers into the formula. I finally got it.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  5. #50
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    Quote Originally Posted by David L Morse View Post
    Do you have the sea breeze/shore breeze cycle? Is there a difference in road traffic weekdays vs weekends? Coal fired power plants nearby? Cement factories? Stone quarries?

    Particle counts are pretty boring where I live.
    So, interestingly, I'm been driven nuts by a fine grit that's been on my car for the last several weeks. I've washed the car so many times that I bought a monthly unlimited membership to a local car wash. I've been speculating that its been salt from the Gulf of Mexico, but puzzled why I'm just seeing this for the first time after living here for 9 months. Kinda scary to think that's getting into the house, and we're breathing it. Much less how delightful that will be on my cast iron machines.

    There has been a pretty constant, sometimes strong breeze from the shore. I'm sure there is an increase in road traffic on weekends, but I'm really separated from the road by a mile and by the Intercoastal Waterway. I also didn't see the numbers go up during Spring Break when traffic was big on the beach road.
    No coal fired plants, cement factories, or stone quarries nearby, thankfully.

    The particle counts from the Dylos amazed me the most when workmen put in a raised access floor and cut the cement panels with a bandsaw. I saw readings of over 35,000 of small particles. I put on my respirator, and offered the workmen some to wear, but they laughed and turned me down. Sadly, I imagine I'll see them in the hospital some day.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  6. #51
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    Quote Originally Posted by Alan Lightstone View Post
    ...I've been speculating that its been salt from the Gulf of Mexico,...
    Well, you could taste it and put an end to the speculation. You're already breathing it.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  7. #52
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    Had a nice conversation with the Dylos rep, and some HVAC guys I know.

    The Dylos rep thinks salt water spray is possible, though not very likely being 1 mile from the beach. Being a couple hundred yards from the Intercoastal, though, makes it more likely.

    The HVAC reps think it is spores from the dry spell getting airborne. Not sure if that's real or not, FWIW.

    Anyway, I've ordered a HEPA unit for our master bedroom, and I'll see how well it works and be able to see the Dylos meter respond. The Dylos rep said to test the unit, after cleaning it with a spray of compressed air in the top vent, to put it in a very small room with that HEPA air cleaner, and let it run for a bit. Then sneak open the door just enough to see the readout. The reading should be VERY low.

    I'll try that in a few days.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  8. #53
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    So, it's been impressively bad here this week for air quality, compared to our usual. The Dylos reads 7503/1244 particles at 10:00pm, which is twice as high as I've ever recorded. It might have been far worse earlier in the day. The AQI is 89 according to the EPA. We set a record high of 98 degrees earlier today. Don't know how that factors in.

    The good news: The HEPA air cleaner I bought for our master suite lowers the levels down to 159/24. I'd say that's a pretty impressive reduction. The new 1900 3M Filtrete filters bring the majority of the house down to 350s and 45ish range. So replacing the HVAC filters with even better ones, and that HEPA air cleaner, work remarkably well.

    The two Jet Air cleaners get the shop down to the 300s when I let them run for a while.

    Now, I have no clue when to be wearing the 3M respirator mask in the shop. 500 used to be my cutoff, as that was the typical ambient air I measured. But now, with the dramatically higher ambient levels - I have no clue.

    I really wish I had brought my Dylos with me when I went to Beijing last year. Here's a typical weekday there, in the expensive hotel room I got with the theoretically spectacular view. You can see that "spectacular" view out the window below. Any clues what the Dylos would be reading that day?
    DSC_1694.jpg
    Last edited by Alan Lightstone; 06-25-2019 at 10:21 PM.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

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