Author Topic: comparing pm2.5 readings  (Read 347 times)

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Offline Platokidd

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comparing pm2.5 readings
« on: February 09, 2023, 06:30:36 AM »
Interesting the data is so far off from each other. The 3 sensors are indoors and about 6 inches apart.
Probably low-end quality?...


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Ambient    
2- WS-2000 2-WS-2902A ARRAYS 1-CONSOLE 2-WH40-RAIN 1-WH31L 1-METEOBRIDGE 2-PM2.5(WH42B)
3-WH-31E 1-SRX100LX 1-WH31SM
ECOWITT
3-HP2552 1-HP2562 1-WH51 10-WH31-2-WH45-3-WH55 1-WH40 2-WS68 1-WS80
5-WH51 1-WH32EP 1-WN30 1-WH41
2-GW2000 2-GW1100
1-HP10

1-Davis 7714
1-Stratus

Offline Gyvate

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Re: comparing pm2.5 readings
« Reply #1 on: February 09, 2023, 08:41:39 AM »
what happens if you calibrate one of the WH41/43 to the same level as the WH45 - and see if the discrepancy remains so big ?
Maybe they only need the same baseline ....
WS2350 1.6.5, GW1000(3) 1.7.6, WH2650 WiFi (2) 1.7.6 (test/backup), GW1100 2.2.7, GW2000(3) 3.0.7, HP2551 1.9.1, HP3500 1.7.2,WN910 1.2.3;
Ecowitt WS90(2), WS80, WH40, WH65, WH31(5), WH31-EP, WN30, WN34L, WN35, WH32, WH32-EP, WH32B, WH57 [Lightning], WH41 [PM2.5] (2), WH51 (6), WH45, WH55
MeteobridgePro(2)[test,prod] 5.6 Jul 2 2023, 15025 - Blake-Larsen Sun Recorder - RPi4/weewx 4.8.0/4.10.2/CumulusMX 3248/Meteobridge RPi4B-2GB(3007)
Barani Meteoshield Pro, MetSpec Rad02 - Ecowitt 5763,34418;WU ISAARB3(WH4000SE), ISAARB22(HP2553), http://meshka.eu

Offline Platokidd

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Re: comparing pm2.5 readings
« Reply #2 on: February 09, 2023, 11:31:25 AM »
Calibrate, I'm holding that thought for a little while..

CH1 is an Ecowitt WH42 outdoor with the Honeywell and fan.
Ch2 is an Ambient model, Honeywell and fan. (wh42 I would assume)
Ch3 is an Ecowitt WH41 outdoor brand new out of the box. This model has no fan that I can see. Not sure how I would clean it.
AQI combo is an Ecowitt WH5. About a year old.
All 4 now are on a table about 5 inches apart.

I have another WH45 that's boxed till my campground opens. Would expect more of the same.

It's mind blowing to see the readings far apart. Leads me to think they're just numbers.
Now what unit to use as baseline.....

« Last Edit: February 09, 2023, 11:36:10 AM by Platokidd »
Ambient    
2- WS-2000 2-WS-2902A ARRAYS 1-CONSOLE 2-WH40-RAIN 1-WH31L 1-METEOBRIDGE 2-PM2.5(WH42B)
3-WH-31E 1-SRX100LX 1-WH31SM
ECOWITT
3-HP2552 1-HP2562 1-WH51 10-WH31-2-WH45-3-WH55 1-WH40 2-WS68 1-WS80
5-WH51 1-WH32EP 1-WN30 1-WH41
2-GW2000 2-GW1100
1-HP10

1-Davis 7714
1-Stratus

Offline Platokidd

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Re: comparing pm2.5 readings
« Reply #3 on: February 09, 2023, 11:43:51 AM »
Update: CH2 (amb) my oldest pm2.5 and the new ecowitt wh41 (CH3) have moved closer.

Ambient    
2- WS-2000 2-WS-2902A ARRAYS 1-CONSOLE 2-WH40-RAIN 1-WH31L 1-METEOBRIDGE 2-PM2.5(WH42B)
3-WH-31E 1-SRX100LX 1-WH31SM
ECOWITT
3-HP2552 1-HP2562 1-WH51 10-WH31-2-WH45-3-WH55 1-WH40 2-WS68 1-WS80
5-WH51 1-WH32EP 1-WN30 1-WH41
2-GW2000 2-GW1100
1-HP10

1-Davis 7714
1-Stratus

Offline Rover1822

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Re: comparing pm2.5 readings
« Reply #4 on: February 09, 2023, 11:55:58 AM »
Interesting, My 2 AmbientWeather (marked as wh42B indoor/outdoor), which I believe at the time , were the same as the Ecowitt WH41 with honeywells, track close to each other. These as the outdoor models have the slower reporting

I am also interested in in how you are doing your testing, what is the environment?, I really don't want to hang out there :)

If you put them in a "cleaner" environment , how do they compare ?

Ambient:
  WS-2000
  PM 2.5(2)
  WH31B(2)
  WH40E
  WH31P
EcoWitt:
  GW1100
  GW1000(4)
  WH31(2)
  WH57
  WH51(12),
  WH40
  WH5360B
  WN34S
  WittBoy WS90 + GW2000
  WS90 (other one) + GW1100
Personal Sites: Weather Cam

Offline davidefa

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Re: comparing pm2.5 readings
« Reply #5 on: February 09, 2023, 03:34:32 PM »
Has been reported that these sensor use different pm sensors ( honeywell, plantower, sensirion ), not sure how the 'compare'... but first of all leave that room as soon as possible!

Offline Platokidd

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Re: comparing pm2.5 readings
« Reply #6 on: February 09, 2023, 05:19:02 PM »
Okay I have moved them. See numbers below. The 2 Honeywell's read fairly close(ch1 &2) The combo and the new ch3 are total different type of set-up / sensor. They also match well. Identical now as I'm typing.
Guessing they all read drastically different as things change for the worse.


Thanks!
« Last Edit: February 09, 2023, 05:24:46 PM by Platokidd »
Ambient    
2- WS-2000 2-WS-2902A ARRAYS 1-CONSOLE 2-WH40-RAIN 1-WH31L 1-METEOBRIDGE 2-PM2.5(WH42B)
3-WH-31E 1-SRX100LX 1-WH31SM
ECOWITT
3-HP2552 1-HP2562 1-WH51 10-WH31-2-WH45-3-WH55 1-WH40 2-WS68 1-WS80
5-WH51 1-WH32EP 1-WN30 1-WH41
2-GW2000 2-GW1100
1-HP10

1-Davis 7714
1-Stratus

Offline kheller2

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Re: comparing pm2.5 readings
« Reply #7 on: February 10, 2023, 01:21:31 PM »
I was going to comment on the two outdoor units I have compared to the AQI combo.  But before I got to do that, I noticed the two outdoor units (using different sensors) are very far apart at times.  My gut is telling me the differences relate to the time of day and when the solar panels have sun on them.  They sit right next to one another. 
Ambient Consoles: WS-2000, WS-1900, WS-1200, WS-2902C, WS-3000-X3, WS-0900-IP(observerIP), WS-1001-WIFI
Ambient Arrays: WH65B
Ambient Sensors: WH31E(3), WH31B(2), WH32B, WH31SM(2), WH31PGW, AQIN, WH31LA(3)
Ambient Spares: WH24B(2), WH25B.
Ecowitt: HP2551BU, GW1000B(dead), GW1100B(2), GW2000B
Ecowitt Sensors: WH51, WN34BL, WN34(2), WH31, WH41, WH40

Offline solartempest

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Re: comparing pm2.5 readings
« Reply #8 on: February 10, 2023, 03:27:58 PM »
My WH41 and WH45 have different readings but are 'close enough' in my determination. Typically within 2-5 g/m3 from each other at the low end. The WH41 was outside since I bought it, even with cleaning I could not get it to match exactly. WH45 stayed inside virtually all the time. Overall, the data trends are very similar when put them side-by-side.
Ecowitt GW1000, HP2553BC, WS80, WH51x4, WH41, WH45, WH40, WH32, WH31x2, WH57x2.