CM bus route signs show PM 2.5 AQI info. How accurate?

[JimmyJ]

On Moon Mueang Road by the Thapae Gate there is a new lightbox "interactive" sign with bus routes.

 

On the upper right it shows several stats including the current PM 2.5 air quality reading.

 

The top picture is (me holding) my SNDWAY SW 825 in front of the sign showing its current reading.

The 2.5 reading is the top figure (largest type).

 

The bottom picture is what CM's sign claims is the reading.

Edited January 18, 2020 by JimmyJ

[Bill97]

Who cares? 
 

Got any sense you don’t need accurate real-time data to see the problem.

[4MyEgo]

I am currently sitting in my 40 square metre room and mine is showing 53 not good, and I live in a country area, windows closed about an hour ago, no cars, trucks or the like around, I would hazard a guess by just getting up now and walking to the other end of the house, I could smell a faint smoke substance in the air, probably someone starting up their dinner over a charcoal fire in the distance.

 

As much as I try not to have the air purifier on all the time, looks like I am either going to have to live with it or reduce the PM2.5 in the air in house by turning it on, which seems to be pretty much an all day thing, suffice to say even if the air doesn't smell the PM2.5 is very evident in or out, so depressing to have to rely on these devices, and I don't know if they are accurate but when I look at other apps, they are pretty much on par with this monitors readings ????

 

[4MyEgo]

6 minutes ago, Bill97 said:

Who cares? 
 

Got any sense you don’t need accurate real-time data to see the problem.

Those that have kids and care for their health, those that do have health issues, e.g. respiratory, heart, lungs, issues, those that are old, do care.

 

Some like yourself know the problem is there all the time, and don't care, others don't know, because they can't see it, can't taste it, so it's not that obvious, but it affects them, you obviously not, but it is internally.

[Bill97]

24 minutes ago, 4MyEgo said:

Some like yourself know the problem is there all the time, and don't care, others don't know, because they can't see it, can't taste it, so it's not that obvious, but it affects them, you obviously not, but it is internally.

What a bunch of <deleted> you made up.  Enjoying life in fantasy land?

[ChaiyaTH]

I will need another purifier for our home for sure, currently have 1 good one and the levels aren't close to the peaks of last year, difficult to keep under 35-40 already. Kind of lame to buy another one as I also know to leave within this year.

Edited January 18, 2020 by ChaiyaTH

[lopburi3]

 

1 hour ago, Bill97 said:

Who cares? 
 

Got any sense you don’t need accurate real-time data to see the problem.

  I seriously doubt if provided by government it will be real time data as they have taken the stance that 24 hour average is what the masses need to know - and until recently Chiang Mai did not consider 2.5 reporting to even be worth the effort.

[Dante99]

39 minutes ago, ChaiyaTH said:

I will need another purifier for our home for sure, currently have 1 good one and the levels aren't close to the peaks of last year, difficult to keep under 35-40 already. Kind of lame to buy another one as I also know to leave within this year.

What does that have to do with the topic which is the accruacy of data on a bus stop sign post?

[ChaiyaTH]

1 hour ago, Dante99 said:

What does that have to do with the topic which is the accruacy of data on a bus stop sign post?

I replied on 4MyEgo but what does your reply have to do with any of both? That is called pointless.

Edited January 18, 2020 by ChaiyaTH

[Dante99]

2 hours ago, ChaiyaTH said:

I replied on 4MyEgo but what does your reply have to do with any of both? That is called pointless.

Boy, you sure got me there.  You are correct, it is pointless since you just can't get the point.

[CharlieH]

Reported post /responses removed.

[4MyEgo]

15 hours ago, ChaiyaTH said:

I will need another purifier for our home for sure, currently have 1 good one and the levels aren't close to the peaks of last year, difficult to keep under 35-40 already. Kind of lame to buy another one as I also know to leave within this year.

Have you checked your windows and doors ?

 

Our place is 4 years young, we have sliding windows and last night watching the Tele, I said to the Mrs can you smell smoke, no, she replied, shouldn't of asked, my Mrs can't smell smoke if it went up her nose, but she will cough, won't wonder why, Thai's don't question things, I cough, I ask myself did I cough, especially when I know the smoke here bothers me, bingo, so I put my detector on the side of the window where they open, and the reading started to climb from 12 to like 52, I put my nose close to the side and smelt the burnt smoke, no doubt from one of many uneducated and selfish people burning their rice and sugar cane fields, oppps, rant, rant, anyways I opened the window and placed the detector on the ledge for a minute and it was showing a reading of 92.

 

I couldn't believe it, so I got the Mrs to grab some cloth rags and we put them all around the windows to reduce/stop the smoke entering. I had put some weather strips around lately thinking they would have stopped it, well, looks like if the wind is up, the smoke will find a way around it, so today its back to the drawing board, will reluctantly and probably seal two windows with silicone as they face the direction of where the smoke is always visible and comes from (open field), but not before investigating things further.

 

What does a bloke have to do to breathe fresh air, it probably was never existent here in Thailand and I was always a dreamer.

[gearbox]

3 hours ago, 4MyEgo said:

What does a bloke have to do to breathe fresh air, it probably was never existent here in Thailand and I was always a dreamer.

Fresh air do exist here in Samui, although Thais are trying hard to pollute it. It is an island in the open sea and no matter how hard they try the wind most of the times wins. The aqi shows 39 now on the internet.

Edited January 19, 2020 by gearbox

[JimmyJ]

On 1/18/2020 at 5:39 PM, lopburi3 said:

 

  I seriously doubt if provided by government it will be real time data as they have taken the stance that 24 hour average is what the masses need to know - and until recently Chiang Mai did not consider 2.5 reporting to even be worth the effort.

 

 

You bring up an interesting point - is the city's data real time or not.

 

I went back to the sign today - it is definitely real time.

 

I watched the sign for several minutes - the longest it held a PM 2.5 number was about 5 seconds before it would move a tenth or a bit more.

 

With yesterday's data (pictured in the OP in a small red box) the city claimed PM 2.5 at the time pictured was 28.90, equaling AQI of 86, while my device showed PM 2.5 of 89 equalling AQI of 168.

 

https://airnow.gov/index.cfm?action=airnow.calculator

 

Today the sign showed PM 2.5 of 15.5 (AQI 58) while my device showed PM 2.5 of 46 (AQI 127).

 

It's now about an hour later.

The lowest AQI Air Visual is showing for Chiang Mai is 74 going as high as 117 depending on the area of CM plus 2 outliers of 135 and 155.

 

To answer my own question in the header - "Accurate?", the answer is NO imo.

(Based on: my device; Air Visual; aqicn.org.).

(In both cases the city's reading was about 1/3 of my device's reading).

 

 

 

 

Edited January 19, 2020 by JimmyJ