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Bangkok Air Pollution 2020

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3 hours ago, TerraplaneGuy said:

Well don't bet too much. I've checked in past to see if the humidity on my Sndway goes noticeably up with the aircon and haven't seen that.  I'll try it again though.  But your thought that there would be a reduction in humidity caused by aircon seems contrary to my observation that particle count goes up with aircon.  I have read that aircon can actually increase humidity, from blowback from the condensation and that's why they include a dehumidify mode on many (there is one on mine) which turns off the fan when the cooling process is not active (i. e. when temperature has reached the desired low level). 

Thanks. Well we know empirically that the A/C evaporators are condensing water from the air because I've captured several liters from one of my units from the drain line on my balcony. I have a GE portable dehumidifier unit that I bought and haven't used much but did play with it a few times. It has a humidity display and a reservoir for capturing the condensate and I can see the humidity being reduced on it's front panel humidity display and water increase in the reservoir when I run it. I've looked at this unit internally out of curiosity and it appears to be a miniaturized version of a full-size refrigerant A/C unit that reduces humidity by cooling the air considerably by passing the air over a cooled, finned heat exchanger (maybe I should have said cold exchanger 😁) I suppose it's probably using thermocouples for cooling the air rather than a refrigerant cycle cooling as do our A/C units. Now that I think about it, I wonder why our A/C units aren't implemented with thermocouples, but this yet another off-topic subject.

 

I suppose that at the same time with full-size A/C units, humidity could be locally increased because of undrained condensate remaining on the evaporator's cooling fins that is being re-evaporated into the air because of the fan continuing to run.

 

Is it possible that out particle sensors are sensitive to both changes in humidity (I'm not going to say reduction this time) and changes in temperature as well?

 

 

 

Edited by MaxYakov

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20 hours ago, Misty said:

Thanks very much for your thoughts.  Thanks to all the upgrades I've made over the last two years, most rooms in our place measure low on my Sndway meter.  Even the big room usually measures low, unless we turn on the old central air conditioners that still exist in that room. I did ask our Thai building manager about installing filters on the intake side for those units, but they said the units are too old and not the same as the US.  So we're left with either no air, or paying to replace those old units ourselves.  Will have to study this some more to see what is most cost effective.  Just getting a small portable a/c is appealing since its cheap.

Thanks for your kind words.  I'm happy that you generally get good air in your home.  About the Central AC making air worse, I've seen a lot of leaky AC Plenums (Ductwork) in the US, and I'm 1/1 (one out of one) with a simple inspection here.  They don't seal the joints.  In the case with the Thai example near Phrakhanong BTS, I just took the outlet cover off and it was quite clear that air was coming from inside the rather-large crawl space between units.

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About humidity influence on Sndway unit...  I tested this the other day putting meter in bathroom during my shower - not much change even with fog on the mirror.  So I put meter in shower with me - then it got rather exciting.  In short, I noticed non-liner behavior when it went from humid to very humid.  Thanks to Max's PDF we can see that when humidity gets above RH 80% the PM count gets a boost from water particles.

I like this RH information on Sndway because I have noticed that the air in Au Bon Pain at Emporium Tower (M level) is usually pretty good (different from outside) suggesting filtered air.  I've tested it many times with 3 different meters.  I don't think it is RH because everything in Emporium buildings is air conditioned and relatively low RH compared to outside. Also Starbucks at Century Onnut has better air.  I'm trying to figure out why.  By contrast, Emporium food court 4th floor glass seating area is exceptionally high AQI around 200-250 at lunch.  Just FYI. Ideas welcome.

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OK I checked once again the effect of aircon on my Sndway PM 2.5 monitor readings.  Results were consistent with earlier tests:  the aircon increases particles.  Details:  Aircon is Daikin recessed wall units in each room with outdoor compressor.  Purifier is the Hatari AP-12.  Test was in my bedroom (not very big). I started with the Hatari at "2" for the whole night, no aircon.  By morning the result was Sndway reading 0-1 at 67% humidity.  Turned on the aircon (fan high, temperature 26) and within a few minutes the Sndway reading was 7.  Humidity unchanged at 67%.  Left if for another 5 minutes or so and the reading jumped to around 14 with humidity down to 62%.  Conclusion:  the aircon caused an immediate jump in particles with no humidity change.  Then particles increased further while humidity went down (the drop in humidity was expected because in the cooling phase of the aircon it sucks up moisture.  It may (see earlier post) blow moisture back into the room in the post-cooling fan phase but I didn't get to that).  The fact that particles increased while humidity decreased suggests to me that the aircon is strongly pumping in real particles, because you would expect a decrease in the particle reading with decreased humidity (since the monitor can mistake water for particles).  Why this happens I don't know.  As mentioned above, I've had the aircon filters cleaned recently and as far as I know no outside air is supposed to get into the system.  Ideas?

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2 hours ago, DaveInSukhumvit said:

By contrast, Emporium food court 4th floor glass seating area is exceptionally high AQI around 200-250 at lunch.

 

Likely the impact of local heat cooking there, gas stoves, frying, etc.

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I have taken to wearing a quality 2.5 mask if outside. It works wonders. I walk about 2 miles a day to gym and back. It works. I breathe full while walking, and do not feel sick when I get home, which has raised my mood in this horrible situation. I no longer feel angry, not wanting to venture out. I noticed difference right away.

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51 minutes ago, WalkingOrders said:

I have taken to wearing a quality 2.5 mask if outside. It works wonders. I walk about 2 miles a day to gym and back. It works. I breathe full while walking, and do not feel sick when I get home, which has raised my mood in this horrible situation. I no longer feel angry, not wanting to venture out. I noticed difference right away.

Good to hear.  How's the air in your gym?

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55 minutes ago, TerraplaneGuy said:

Good to hear.  How's the air in your gym?

Air conditioned 

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On 2/26/2020 at 4:42 PM, TallGuyJohninBKK said:

 

Somehow, AQICN.org seems to be predicting BKK PM2.5 levels for Thur and Fri of up to 248 AQI...  In the two or so years I've been monitoring this closely, I don't think I've ever seen BKK at large hit a pollution level that high.

 

143627803_2020-02-2616_40_46.jpg.9cbac39e284e2b9fcc984ab3bb1d46a6.jpg

 

 

Never got to purple / very unhealthy today in BKK, even though the PM2.5 levels have been generally rising ever since late morning. So yesterday's forecast appears to have been off, at least for today. And we just had to settle for regular RED / UNHEALTHY!

 

1756542588_2020-02-2719_44_31.jpg.3e2008531a985935498beb3c34ab4385.jpg

 

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9 hours ago, WalkingOrders said:

I have taken to wearing a quality 2.5 mask if outside. It works wonders. I walk about 2 miles a day to gym and back. It works. I breathe full while walking, and do not feel sick when I get home, which has raised my mood in this horrible situation. I no longer feel angry, not wanting to venture out. I noticed difference right away.

What brand and which store you got it from? Masks are going empty shelf/stock in stores in my neighborhood and instead, home made masks are appearing on sidewalk stalls, bearing PM 2.5 even though they are made out of cloth and sporting a breathing valve no less - 100 baht a piece. Thanks.

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On 2/27/2020 at 12:43 PM, WalkingOrders said:

Air conditioned 

Meaning gym membership places have same AQI like outside.  I've only found 2 coffee shops in dozens of meter tests that appear to be semi purified air.  In general, nobody sells air conditioning filters here in Thailand (AFIK), especially not HEPA filters.  That means no filters for Wall-hang units, no for Cassette units (ceiling square design), no for central ducted split units.   I did see a customizable HEPA shop online one time, I think this is it: https://www.facebook.com/SRPFRESH/)   Corrections always welcome.

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Well folks as we know the late, great "Purple/Unhealthy" forecast (Ref. HERE) for Thursday and Friday was not a happening, especially not for Friday. If I weren't trying to be nice, I'd call the forecast "bogus". Anyway, late last night and early this morning I attempted to do a post-mortem on the situation and Venusky offered a potential explanation - there was not a source of external-to-Bangkok pollution by 23:45 last night (Friday, the 28th). The Venusky display for around midnight follows this two-day summary from RTAQI:

 

RTAQ_022920_0128.jpeg.c2c39e5c1ab4c815e700ad71efe66836.jpeg

 

As can be seen, the southerlies from the Gulf of Thailand via the Bay of Bangkok seem to have held off the western coast Thai/Myanmar pollution except to the northeast of Bangkok where some has gotten through. Cambodia is being skirted by winds that Venusky says skirt around the southern tip of Cambodia.

 

Note: I don't necessarily trust Venusky displays much more than I do the RTAQ pollution forecasts. They admit that their display is a computer model driven from data that could be up to eight hours old. In any event, this particular display from 2345 last night could be used to explain the Moderate/Orange levels we saw yesterday (Friday) from 1600 until 0000. 

 

VUS_022820_2345.jpeg.d75fb88878b226ee8303ccb8c63ef3d9.jpeg

 

 

 

 

 

Edited by MaxYakov
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3 hours ago, MaxYakov said:

As can be seen, the southerlies from the Gulf of Thailand via the Bay of Bangkok seem to have held off the western coast Thai/Myanmar pollution except to the northeast of Bangkok where some has gotten through.

That's it.

And now the PM2.5-pollution is rising again?

 

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14 minutes ago, Yom said:
3 hours ago, MaxYakov said:

As can be seen, the southerlies from the Gulf of Thailand via the Bay of Bangkok seem to have held off the western coast Thai/Myanmar pollution except to the northeast of Bangkok where some has gotten through.

That's it.

And now the PM2.5-pollution is rising again?

There is some currently shown by Venusky in northern Bangkok for what that's worth. However, if it's coming from the north, it's going against the southerly winds that are spanning Bangkok (according to Venusky). It appears to be part of a large area of >50 and >100 pollution to the north and northwest. I should look to FIRMS for high field fires in the north and northwest I suppose.:

 

VUS_022920_1550.jpeg.d664bd73dc7d1404fcb4e6c694b1470a.jpeg

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30 minutes ago, MaxYakov said:

... if it's coming from the north

Might be the remnants of days before?

You should be happy today in Bangkok. Hope so.  -  I think,

the 'clean' winds from the Gulf of Thailand are fighting with the air pollution

originating from India and Myanmar. And the winner seems to be the Gulf winds.

They push a lot of the smog to the Andaman Sea and the rest up North.

There it is really bad these days.

 

Edited by Yom
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