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Summertime Outdoor Air CO?

NY_Rob Member Posts: 1,370
Last Saturday when down in my basement my five month old Sensorcon Inspector carbon monoxide detector was displaying 22ppm on it's LCD. I was shocked because no one but me was home, I have no standing pilot devices in the basement any longer, the mod-con is externally vented with no call for DHW for hours... no one was using the oven/stove- all in all- no combustion was going on inside my house for hours before I noticed this reading.
I decided to take the meter outside to clear the reading then go back inside and investigate.
Upon exiting the house- instead of lowering- the reading went up to 23ppm, then 24ppm as I moved a bit farther from the house. I then walked a few houses down the street with meter in hand- it varied between 23-25ppm. I left it out on my patio table all afternoon, a couple hrs later it went back down to 17ppm, then 9ppm and eventually back to 2ppm and 0-1 ppm that evening and by that time the basement and house were back down to 0-1ppm too.

FWIW- I haven't used the Sensorcon during the summer- I purchased it in Feb where the ambient outdoor CO is usually 0 or maybe 1-2 briefly. I've never take outdoor summertime CO readings before.
Has anyone seen something like this 22-25ppm reading outdoors in the open?


  • Jamie Hall
    Jamie Hall Member Posts: 22,936
    smog, laddie, smog. Great stuff.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • captainco
    captainco Member Posts: 792
    It was outdoor pollution but not necessarily CO. See answer on drain CO.
  • captainco
    captainco Member Posts: 792
    That just happened to me this weekend while teaching in Rochester, NY. Put my Inspector on my belt and it started reading 18 ppm and beeping. Went outside and it did the same things. A little bit of fog outside but they are waterproof. I know they pick up butt odors but it wasn't me. Aftershave or cologne can affect them also. It hasn't happened since then. Have to wait until it happens again and see if there are any similarities.
  • ChrisJ
    ChrisJ Member Posts: 15,473
    If I let one rip and it sets off a CO detector I am definitely bragging about it.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Fred
    Fred Member Posts: 8,542
    Any issues with Radon in those areas? Are any of those areas built over old land fills? I don't know if Radon will register on those detectors but I'm sure methane will. Just a thought.
  • NY_Rob
    NY_Rob Member Posts: 1,370
    On Long Island we don't have Radon issues because of the geological substructure. But we do have Brooklyn, Queens, Manhatan and Jersey nearby- so that would account for occasional "bad air".

    One other time this summer my Sensorcon read 18ppm CO in the house... I brought it outside and it read 19! It usually reads around 0-1-2ppm indoors and outdoors.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    I have had issues just after the lawn care folks sprayed the lawn. It does however disappear after a while.