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Thread: Indoor air quality monitor.

  1. #1
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    Indoor air quality monitor.

    I have customer who wants to know if there is a quality indoor air monitor. they want to install it to see if there is going to be a difference now and after we do filter changes maybe add a phenomenal air type device. Does anybody have any experience for any or any suggestions
    Ty


    Sent from my VS988 using Tapatalk

  2. #2
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    Careful they might discover that the filters don't do anything for their air and the meter won't show them how well the filters protect the evaporator coil.

    Sent from the Okie state usin Tapatalk

  3. #3
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    I use to take care of some state air monitoring stations placed at different highly traveled locations in Maryland at one time. The trailer equipment measured everything using very expensive equipment. To my knowledge that is no reasonably priced air monitoring equipment that most any home owner would want to purchase. I know over the years I've run into people who had some small air monitors for their labs but those were also very expensive as I was told. If you can find decent, reasonable priced test instruments for measuring the quality of the air let us all know. All of use would have customers that would purchase them on the spot. The one easy test that I do remember from these road side trailers was a high speed small propeller fan where they put a white cloth across the discharge then watched how soon it got dirty. They would also take the white cloth into their labs to examine what was also on the cloth that the eye could not see. One thing I learned is the the air is a lot more dirties than we could ever suspect.
    "The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
    - Alexis de Toqueville, 1835

  4. #4
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    .

    Google "Air Advice".
    ..
    Do not attempt vast projects with
    half vast experience and ideas.
    ...

  5. #5
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    Madison, WI/Cape Coral, FL
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    After a few years of trying different devices, I have gone back to measuring CO2 levels to assure adequate fresh, filtered air change rate when the space is occupied.
    I setup mechanical fresh filtered ventilation to provide a fresh air change in +-4 hours rather that try to filter out the indoor pollutants because of the need for maintaining +18% oxygen. Set the for ventilating at 600 PPM CO2 which would be about +75 cfm with a single occupant. That way no mechanical ventilation when unoccupied or enough wind/stack effect to maintain low <600 PPM CO2. We do not even know about all of different indoor pollutants, much less be able to do accurate measurement. Suggest a Merv 13 air filter.
    If you are in a green grass climate, include a small whole house dehumidifier to maintain 50%RH during evenings and rainy or damp weather. Units like Ultra-Aire dehumidifiers have a fresh air option and Merv 13 air filters that you can use a CO2 controller for fresh air.
    For just monitoring the indoor/outdoor temp/%RH, CO2 levels, noise levels, and rain gauge, consider the Netatmo monitor. Phone APP included.
    Netatmo.com

    Keep posted on what you do and how it works.
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
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    It sounds like you are most interested in measuring particles. I personally use an optical particle counter that costs around $4,000. I have personally seen that a low-cost Dylos isn't too far off from my calibrated device. For $200, a Dylos will provide a homeowner with some basic information.

    Remember that filters with some loading can have improved efficiencies over brand new filters. So don't be surprised if the particle counts stay the same after a filter swap (or worse, particles go up).
    Ian Cull, PE, CIH
    Indoor Science
    Chicago, IL

  7. #7
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    I second Ian's recommendation of the Dylos device for measuring particulate levels. The device uses the same technique, laser scattering, that is used in high cost industrial units and delivers an accurate and consistent reading. Recently laser and led modules have become available the pacific rim. Some companies are incorporating these device in low cost units. I haven't tested personally but some data I've seen is promising.

    The phenomenal device (GPS technology) "might" reduce PM pollution (particulate matter) - there is some academic research that this approach can be effective. But, unlike HEPA filtration, smaller particules group together to form bigger particles that either fall to the ground or accumulate to horizontal configured ducts. These larger particles can also be trapped more efficiently by lower rated filters. Vacuum often.

    Measurement of VOCs is trickier. I've used three techniques.

    1. Independatn labs offer GC/MS technology. These labs send a small test to take a calibrated sample. The sample is returned and a report generated.
    I've used two labs
    https://www.homeaircheck.com/
    https://www.fikeanalytical.com/

    2. PID meter - These instrument will provide immediate readings in real time. Unless you know the VOCs in the area you are measuring the readout will not necessarily match a lab test. But readings are consistent and will accurately indicate if levels are increasing or decreasing. Unfortunately these devices are expensive ~ $8K. They are available for rent though.

    3. Metal Oxide Semiconductor devices. In the last few years a new semiconductor technology has become available in low cost consumer units. Early rendition of the technology suffered a number of short comings. Recently the technology has improved to the point that some of these devices are useful. Although I wouldn't trust the "absolute reading" on these devices, the relative changes, IMHO, are useful. So you can take a reading before and after the phenomenal air device is turned on to note changes.
    This is really exciting as companies claim to reduce VOC can be tested. Until recently this was out of reach of most home owners and professionals. Many companies are selling devices that don't do what they claim.
    I currently use the Temtop M10. It's about $90 and very effective, I think?, for monitoring relative changes. i.e. -Could be useful for monitoring relative VOC changes.

    I do Not believe that the phenomenal device(GPS) is effective, despite GPS claims to the contrary, for VOC reduction. The science that GPS use is bogus. They confuse "ionization" with "oxidation". Also the data they provided to support their VOC claims is double speak gibberish.

    Particulates are easy, VOC (other than ventilation and adsorption) is difficult.

  8. #8
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    Jun 2020
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    Good summary randyf!

    I'm personally not a big fan of low-cost VOC sensors. The metal oxide semiconductor sensors themselves cost $2 - $10 and get packaged into devices that sell for around $100 - $200. Yes, they can detect a large change in VOCs (e.g. when taking the cap off a marker right next to it), but my experience is that they cannot identify small fluctuations in VOC levels. I use expensive PID meters (ppbRAE 3000, graywolf) for VOCs, but I realize these are out of the price range of most people. I hope the pricing of PID sensors comes down over the coming years.
    Ian Cull, PE, CIH
    Indoor Science
    Chicago, IL

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