Air quality monitor - my online purchase is rubbish!

[simon43]

Concerned about the PM2.5 air quality, and the lack of online data for my location (the websites simply interpolate data from 2 distant monitors in other cities), I bought a monitor off Aliexpress.

 

Well, the unit switches on, displays a PM2.5 value, and that value increases as the smoke density rises.  But the values seem completely at odds with the online interpolated data.

 

In my garden, the normal reading is about 20, which I refuse to believe as correct, (Phuket has very clean air and typically has a value of about 50 - I live in the hills with local scrub burning at times).  Online data suggests about 70.  If I walk past a dusty building site, the value rises to about 55.

 

The monitor is made by a Chinese company called 'Total B0ll0x Factory #5'.

 

Can anyone recommend an accurate air quality monitor that I can buy from Aliexpress (not Lazada - I live in Laos)?

Edited February 11, 2020 by simon43

[Speedo1968]

Trust in your nose, eyes and how it feels inside you ( i.e. lungs ) etc. far more accurate and reliable.

[Samuel Smith]

On line data is normally AQI.  Sensors measure pm2.5.   Not the same.

 

Convert pm2.5 to AQI here https://www.airnow.gov/index.cfm?action=airnow.calculator

Edited February 11, 2020 by Samuel Smith

[Pravda]

1 minute ago, Samuel Smith said:

On line data is normally AQI.  Sensors measure pm2.5.   Not the same.

 

Convert pm2.5 to AQI here https://www.airnow.gov/index.cfm?action=airnow.calculator

 

This. 

 

It seems like Simon's knowledge of pm 2.5 is Total B0ll0x Factory

 

PM of 20 is AQI 67. 

[simon43]

2 minutes ago, Samuel Smith said:

On line data is normally AQI.  Sensors measure pm2.5.   Not the same.

 

Convert pm2.5 to AQI here https://www.airnow.gov/index.cfm?action=airnow.calculator

Ah ha!!!!!

 

Thank-you very much for putting me right ????

 

So my reading of 20 equates to 68 AQI.  That sounds more like it.

[Pravda]

And just for the reference how filthy and polluted bangkok air is, my xiaomi filter works all night on auto in in 6sqm bedroom and it still shows a pm 22 which is AQI 71

[lopburi3]

1 hour ago, Pravda said:

And just for the reference how filthy and polluted bangkok air is, my xiaomi filter works all night on auto in in 6sqm bedroom and it still shows a pm 22 which is AQI 71

That is not the air - it is either a misreading or your filter is <deleted>.  6 square meters is tiny (are you sure - do you have walls)?  My bedroom of 26sm is always below 10 reading (AQI 42) using Hatari AP-12 at med speed no matter how dirty the air here in Bangkok.  

[simon43]

My current PM2.5 reading is 119, which equates to an AQI of 184, (rather high).  I took a walk around town and the mountains are very obscured, hence the high reading.  But this is early 8 am in the morning, with morning mist.  Can mist affect the monitor readings?

 

I'll check again later in the day when the sun has burnt off the mist.

[lopburi3]

8 minutes ago, simon43 said:

My current PM2.5 reading is 119, which equates to an AQI of 184, (rather high).  I took a walk around town and the mountains are very obscured, hence the high reading.  But this is early 8 am in the morning, with morning mist.  Can mist affect the monitor readings?

 

I'll check again later in the day when the sun has burnt off the mist.

Are you currently in LP?  That is the mountains so if you can not see them a bit of a worry.  Laos does not concern itself with air quality and suspect rather cold this time of the year so open fires may indeed be making air worse than normal.

[simon43]

I don't (nowadays) have a lung problem, and I do have an N95 mask.  I'm sure that Luang Prabang suffers like many rural areas with stubble/crop burning problems when it's that season.  My AQI is now down to 165 and falling, and I can see the mountains more clearly.

 

I hope to link my air-quality monitor into my website so others can check the value in real-time ????

[Pravda]

4 hours ago, lopburi3 said:

That is not the air - it is either a misreading or your filter is <deleted>.  6 square meters is tiny (are you sure - do you have walls)?  My bedroom of 26sm is always below 10 reading (AQI 42) using Hatari AP-12 at med speed no matter how dirty the air here in Bangkok.  

 

Well, when I put it on highest mode the pm levels will drop to 002-004 so I dont think it's the filter or the sensor. 

[tpkhk]

Looks like you sorted the issue - but fyi - 

Makerspace Thailand makes their sensors in Chiangmai and seem to have quite a few positive reviews -

https://makerspace-thailand.myshopify.com/products/air-tricorder-portable-aqi-sensor

 

The portable monitors sold by Xiaomi (unfortunately via Lazada) run about THB 850.  Dont know how accurate.

[lopburi3]

1 hour ago, Pravda said:

 

Well, when I put it on highest mode the pm levels will drop to 002-004 so I dont think it's the filter or the sensor. 

Have seen reports on that cleaner Auto setting being very ineffective and that can not use in other modes more than a few hours or will reset.  So appears to be a program issue.  Believe that was the (2) model so not sure if all the same.  My Hatari just keep at fan speed 2 all the time and never measure more than 10 - change the filter every six months.

[Fore Man]

I bought the Xiaomi pager-sized monitor and ours is dead on with their three air purifiers I bought last year as well as the AirVisual app on my phone, when I look at PM 2.5 values. This bake is found in the app display but not as the main AQI value. 

Edited February 12, 2020 by Fore Man
Typo

[SiSePuede419]

Google "AQI (insert your city here)."

 

Free. ✓

 

PS Why do you care what the AQI is outside?  You should be more concerned what the AQI is indoors, especially your bedroom where you sleep and recharge your brain, dude.

 

Second the Xaomi recommendation, but instead of a handheld monitor that does nothing get an actual air purifier that has an AQI display on it. ????

Edited February 12, 2020 by SiSePuede419

[Fore Man]

8 minutes ago, SiSePuede419 said:

Google "AQI (insert your city here)."

 

Free. ✓

 

PS Why do you care what the AQI is outside?  You should be more concerned what the AQI is indoors, especially your bedroom where you sleep and recharge your brain, dude.

 

Second the Xaomi recommendation, but instead of a handheld monitor that does nothing get an actual air purifier that has an AQI display on it. ????

I hasten to add that the portable monitor can tell you the PM 2.5 levels in places other than your home...such as when taking exercise outside or while visiting a mall etc.  If you’re the type that enjoys any outdoors activity, it’s crucial that you understand when to either remain inside or wear an air respirator (N95) mask.  You’d be surprised at how dirty the air can be in almost any public building.  The top floor at Central Festival was recording PM 2.5 of 145-155 when it was 220 outside. And yet the people blithely strolled around, oblivious to the hazard to their health. The only exception I’ve seen is a recently-built hospital in Chiang Mai that was fitted with HEPA filtration in its HVAC system.  This same facility was also designed to LEED standards, which are far more stringent and meet ecological ‘green’’ building codes. The other area hospitals don’t even come close to being safe.  Most late model cars have fine particular filter and you can use your portable monitor to tell exactly how much protection you are getting.  Of course there are those expats who ignore all the AQI hoopla, but I think they’ll regret that mistake few years in the future. 

[CHdiver]

7 hours ago, simon43 said:

Can mist affect the monitor readings?

Mist probably traps the pollution closer to the ground. At least that is my experience here in Switzerland. My airpurifier (actually a waist of money here if you have no allergies) shows much higher levels (up to 20 PM 2.5) if mist is present outside and I air my appartment. Normally it will not move much higher then 6 to 8 PM 2.5.

[emptypockets]

10 hours ago, Pravda said:

And just for the reference how filthy and polluted bangkok air is, my xiaomi filter works all night on auto in in 6sqm bedroom and it still shows a pm 22 which is AQI 71

Are you in jail? 6 sq m?

[emptypockets]

1 hour ago, Fore Man said:

I hasten to add that the portable monitor can tell you the PM 2.5 levels in places other than your home...such as when taking exercise outside or while visiting a mall etc.  If you’re the type that enjoys any outdoors activity, it’s crucial that you understand when to either remain inside or wear an air respirator (N95) mask.  You’d be surprised at how dirty the air can be in almost any public building.  The top floor at Central Festival was recording PM 2.5 of 145-155 when it was 220 outside. And yet the people blithely strolled around, oblivious to the hazard to their health. The only exception I’ve seen is a recently-built hospital in Chiang Mai that was fitted with HEPA filtration in its HVAC system.  This same facility was also designed to LEED standards, which are far more stringent and meet ecological ‘green’’ building codes. The other area hospitals don’t even come close to being safe.  Most late model cars have fine particular filter and you can use your portable monitor to tell exactly how much protection you are getting.  Of course there are those expats who ignore all the AQI hoopla, but I think they’ll regret that mistake few years in the future. 

Understand where you are coming from, but what kind of life is to wear an N95 mask for the majority of the time. Maybe time to move somewhere with cleaner air?

[buick]

i was wondering about the PM2.5 reading versus AQI.  thanks for the clarification on that.  i'm having trouble getting below 20 (PM2.5) at my place with an air purifier that is brand new so not a filter issue yet.  i guess i'll leave it on longer and see what happens.  thanks again.

[motdaeng]

10 minutes ago, buick said:

i was wondering about the PM2.5 reading versus AQI.  thanks for the clarification on that.  i'm having trouble getting below 20 (PM2.5) at my place with an air purifier that is brand new so not a filter issue yet.  i guess i'll leave it on longer and see what happens.  thanks again.

... some do forget to unpack the filter when buying a new air puriffier ...

[OneMoreFarang]

What's the point in knowing the exact value?

I have to admit I also look at the values (in Bangkok) from time to time online. But if it's 50 or 150 does not change what I do or don't do. And if it is really bad I only have to take a look out of the window to know it's bad.

 

And just in case you really want to know. Then why buy a cheap no-name product from China? That's useless. If you really want to know then buy a quality product from a brand name company. Then you will know the exact value - and your knowledge won't change anything. ???? 

[OneMoreFarang]

11 minutes ago, motdaeng said:

... some do forget to unpack the filter when buying a new air puriffier ...

I guess that's why they have all those unboxing videos. ???? 

[simon43]

Google "AQI (insert your city here)."

 

... and that's exactly why I bought a monitor.  Websites like Air Visual list thousands of city locations.  But in fact, they DON'T have air quality monitors in all those cities.

 

In my case, although a search for Luang Prabang brings up a measurement for my town, what the website doesn't tell you is that it's an interpolated data value, with the nearest air quality monitors being hundreds of Km away in Vientiane, Nan and southern China!

 

Having sorted out the micrometer/cubic metre vs AQI misunderstanding, I'm happy that my monitor is giving me an accurate reading, based on looking at the smoke haze on the nearby mountains in the morning.

 

The PM2.5 value inside my house is very low, so I'm not concerned about that.  But I jog early each day and then also walk later in the day.  It's nice to have an idea of the AQI in my location, rather than rely on interpolated data.

 

I've put my monitor online at www.lp.guide.  Since it doesn't have a data output connector, I've done a 'Heath-Robinson' with a webcam viewing the monitor, and then FTP upload of the photo to my server every minute.  It works!  (After 7 pm, the monitor is offline to recharge the batteries, but I'll try to switch it back online at 5 am each morning).

[GeorgeCross]

i have a SNDWAY SW-825 and i like it a lot - way more sensitive than my xiaomi air purifiers that always read too low but matches local station (1km away) nicely when i use it outside

 

cost me about 1500bht from lazada.

 

Edited February 12, 2020 by GeorgeCross

[fxe1200]

Never forget to check the air quality underneath the duvet of your bed, as the frass of the mites, which populate the bed sheets and the matress, adds significantly to the amount of particle matter!!

Edited February 12, 2020 by fxe1200