Bangkok Air Pollution 2020

[thedemon]

6 hours ago, TallGuyJohninBKK said:

 

There have been a lot of studies on the subject of source... and the mix of sources tends to vary between the wet season (more vehicle based) vs. dry season (more burning based), along with weather and other factors...

 

But the way I look at it overall is this: the vehicles are a baseline. With few exceptions, the traffic is ALWAYS bad in BKK and there tend to be pretty much the same levels of vehicles on the roads. And yet this time of year, the smog is absolutely the worst, which more than just happens to coincide with the agricultural burning season.  When the morons out there are not burning their fields (whether it be Thailand or adjoining areas), the smog in BKK never gets to the levels like it is right now.

 

 

I agree with your assessment except that, if we're talking about greater Bangkok I think you might be underestimating the effects of seasonal weather patterns i.e. wind strength and direction and overnight temperature.

 

A week ago the PM2.5 was much lower that it is now and there is no other obvious reason for that.

[TerraplaneGuy]

3 hours ago, thedemon said:

 

I agree with your assessment except that, if we're talking about greater Bangkok I think you might be underestimating the effects of seasonal weather patterns i.e. wind strength and direction and overnight temperature.

 

A week ago the PM2.5 was much lower that it is now and there is no other obvious reason for that.

Agreed.  Earlier in this string we discussed the fact that ordinarily the air quality is worse at night than in the afternoon (not only in BKK but most major cities), probably owing to heating and inversion effects.  But I notice recently that pattern seems to have broken.  We've been getting almost uniformly bad air 24/7.   Clearly there are many factors that influence this and again my take is that rather than try to analyze it we should (those of us who can) just get out.  Stay for the rainy season if you don't mind the rain, at least the air is OK.  But winter is dangerous.  The depressing fact for those of us who like Asia is that this situation applies to almost all big cities.  I was looking at Busan, Korea which is a beautiful seaside city and its historical AQ is worse than BKK.  I'm now looking at spending winters in Europe or North America and maybe heading back here for summer, which from a climate perspective is a bit perverse but works for AQ.

[codebunny]

What do you think the chances are of the govt funding electronic air pollution monitoring systems?

They have some screens for traffic that I've seen, but nothing significant to monitor urban air pollution.

 

[TerraplaneGuy]

2 minutes ago, codebunny said:

What do you think the chances are of the govt funding electronic air pollution monitoring systems?

They have some screens for traffic that I've seen, but nothing significant to monitor urban air pollution.

 

Zero if you mean anything much more than what they already have.  There are some govt monitoring stations.  But every indication is that the govt prefers to minimize information on the bad air, not publicize it.  If more people get upset, they might actually have to do something about it.  So no.

Edited February 4, 2020 by TerraplaneGuy

[Guest]

On 1/7/2020 at 1:56 PM, hrrecruiter said:

Like you, I love this city but I had enough. Packing as I type this and planning to leave Q2 2020 after many years. 

Wish you the best!  By the way, was air quality the ONLY reason?  Or are there other issues?  

[Yom]

Today back to the OP.

Pravda said:  ' When is it going to be enough for you guys? '

 

For me the handling of the air pollution problem in Thailand since years

is far beyond any intelligent behavior.

If there were no familary reasons to stay, I would leave tomorrow.

 

So, if you would like to have some info about the dust situation

up North, starting Jan 15, 2020, here is a/my link:

https://forum.thaivisa.com/topic/1143398-phrae-pm25-numbers-2020/page/4/#comments

 

Excuse me, some of you posters on the BKK-forum.

It's not the time to discuss the existing problem, it is time to act,

not to babble.

 

 

[TallGuyJohninBKK]

FYI, there were a couple of major research reports issued lately on PM2.5 pollution, including one that said even below-standard levels of PM2.5 pollution will increase the public's chances of heart attacks and similar problems, especially in older people.

 

https://www.cnn.com/2020/01/28/health/air-pollution-heart-disease-study/index.html

 

Quote

 

Even short-term exposure to low levels of air pollution can increase risk of cardiac arrest

Updated 9:02 PM ET, Tue January 28, 2020

 

(CNN)Short-term exposure to air pollution is linked to a higher risk of sudden heart problems, especially among older people, according to a study published Monday.

...

Researchers found that with every 10 micrograms per cubic meter increase in PM2.5., there is a 1-4% increased risk of cardiac arrest. For patients older than 65, researchers found a significant association between PM2.5 exposure and increased incidences of cardiac arrest.

...

The study concluded that "to date, no threshold level of PM is advised as safe for the general population," adding that "current air quality standards need to be reassessed with consideration for efficient strategies to reduce air pollutants to as low a level as possible."

 

 

Edited February 4, 2020 by TallGuyJohninBKK

[Jajazazajaja]

Absolutely gorgeous today, can see all the way to the airport from PraKhanong. Can’t see any pollution haze at all 
 

what happened?

[Guest]

1 hour ago, Jajazazajaja said:

Absolutely gorgeous today, can see all the way to the airport from PraKhanong. Can’t see any pollution haze at all 
 

what happened?

The seasons are changing, and the wind is coming right out of the south ... over the water ... not the north ... over the burning fields.  Here is an app I think you will enjoy to let you see wind, precipitation .. etc.
https://www.ventusky.com/?p=13.34;100.78;6&l=rain-3h

[seb2015]

On 2/14/2020 at 7:20 PM, bangkokequity said:

The seasons are changing, and the wind is coming right out of the south ... over the water ... not the north ... over the burning fields.  Here is an app I think you will enjoy to let you see wind, precipitation .. etc.
https://www.ventusky.com/?p=13.34;100.78;6&l=rain-3h

That's a very nice app , I wonder how future predictions can be accurate ?

I can see that the next date at which wind should blow from the gulf onto the capital is next monday , too bad , I really enjoyed the weekend .

Hopefullly we're nearing the end of the burning season 

 

 

Side question : does anyone have experience with centrally distributed aircon systems (i.e. VRV) and how easy it is to insert PM2.5 / HEPA filter pads in the main air pipe ?

We're building a house in the city and this looks like a more expensive setting vs individual aircon units in all rooms, but if it allows me to worry less about purifying the air in every room , I'm down with this option..

 

[ThomasThBKK]

12 minutes ago, seb2015 said:

That's a very nice app , I wonder how future predictions can be accurate ?

I can see that the next date at which wind should blow from the gulf onto the capital is next monday , too bad , I really enjoyed the weekend .

Hopefullly we're nearing the end of the burning season 

 

 

Side question : does anyone have experience with centrally distributed aircon systems (i.e. VRV) and how easy it is to insert PM2.5 / HEPA filter pads in the main air pipe ?

We're building a house in the city and this looks like a more expensive setting vs individual aircon units in all rooms, but if it allows me to worry less about purifying the air in every room , I'm down with this option..

 

 

Windy is another nice app for wind: https://www.windy.com/?13.709,100.455,5

 

We are however still not good with weather predictions, it simply takes too much computing power. Long term predictions are near impossible. 

[MaxYakov]

55 minutes ago, seb2015 said:

That's a very nice app , I wonder how future predictions can be accurate ?

I can see that the next date at which wind should blow from the gulf onto the capital is next monday , too bad , I really enjoyed the weekend .

Hopefullly we're nearing the end of the burning season 

 

 

Side question : does anyone have experience with centrally distributed aircon systems (i.e. VRV) and how easy it is to insert PM2.5 / HEPA filter pads in the main air pipe ?

We're building a house in the city and this looks like a more expensive setting vs individual aircon units in all rooms, but if it allows me to worry less about purifying the air in every room , I'm down with this option..

 

I don't have the experience with a centrally-distributed A/C system, but I have installed a 5-bladed 30W fan driving into an Hatari HEPA filter for one of their air purifiers and can say without doubt that a common, consumer HEPA filter gives a high resistance to airflow. The HEPA filter material is extremely dense and seems to be impregnated with some kind of chemical. If anyone can comment on the availability of an HEPA consumer air purifier that also provides high-volume air flow, I'm all ears.

 

I have also modified an evaporative cooler to pull air through an older and slightly smaller Hatari HEPA filter and it also provides a high resistance to high-volume air flow. In both cases I have removed the carbon granule layer from the filters in an attempt to reduce air restriction through the HEPA filters because I've added a single layer of 3M Filtrete filter material as a pre-filter on the input sides of the HEPA filters. Yes, the Filtrete layer increases resistance, but even without it the flow impedance offered by the HEPA filters is very high.

 

So, I believe high-volume air flow is not doable through the standard, common HEPA filters that are found in most consumer air purifiers. High-volume air flow filters that would give an HEPA level of particle removal may be available, but it is probably based on a different technology than the HEPA filters found in common consumer air purifiers. Perhaps electro-static or rapid flow-change or oil-bath based approaches? 

Edited February 17, 2020 by MaxYakov

[DaveInSukhumvit]

On 2/17/2020 at 12:41 PM, seb2015 said:

That's a very nice app , I wonder how future predictions can be accurate ?

I can see that the next date at which wind should blow from the gulf onto the capital is next monday , too bad , I really enjoyed the weekend .

Hopefullly we're nearing the end of the burning season 

 

 

Side question : does anyone have experience with centrally distributed aircon systems (i.e. VRV) and how easy it is to insert PM2.5 / HEPA filter pads in the main air pipe ?

We're building a house in the city and this looks like a more expensive setting vs individual aircon units in all rooms, but if it allows me to worry less about purifying the air in every room , I'm down with this option..

 

Re "end of burning season" - AFIK, the waste-to-energy plants around BKK don't have a season. The coal power plant in the South doesn't either.  Also garbage burning, plastics burning, and electronics recycle/burning are a problem only abated by wind direction or govt order.  If you believe the news, then contracts for importing containers of plastic from other countries expire at the end of 2020, so that should help with dioxins, etc..

Re: central air systems and filters - I did a central system installation in Florida as a hobby for an add-on.  So I'm no expert, but more than a little hands-on.  In US it is easy to find the 4" thick hepa filters of all shapes and sizes at home depot, lowes, etc.  Do a google image search on "20 in. x 25in x 4.375 in. Pleated Hepa filter" to see.  Here in BKK, Home Pro does not stock any comparable hepa filters (only Hatari Rap 1201, or Filtrete).  The lack of availability is a concern.  I suspect, in time, there will be options - but unless someone knows better, they are few and far between at the moment.

If you did have a HEPA source for large filters, then a 2000 - 3000 sq ft home with 2-4 BR could be cooled with one central AC unit - they do it all the time in Florida.  But those spit systems require a large pad outside and air handler inside.  I think it is far less expensive to go with Purifiers in every room.

.. Improvements welcome ????

[mtls2005]

AQI forecast for this week looks dismal...no clue how accurate that forecast is though.

 

 

 

[Misty]

On 2/18/2020 at 2:48 PM, DaveInSukhumvit said:

Re: central air systems and filters - I did a central system installation in Florida as a hobby for an add-on.  So I'm no expert, but more than a little hands-on.  In US it is easy to find the 4" thick hepa filters of all shapes and sizes at home depot, lowes, etc.  Do a google image search on "20 in. x 25in x 4.375 in. Pleated Hepa filter" to see.  Here in BKK, Home Pro does not stock any comparable hepa filters (only Hatari Rap 1201, or Filtrete).  The lack of availability is a concern.  I suspect, in time, there will be options - but unless someone knows better, they are few and far between at the moment.

If you did have a HEPA source for large filters, then a 2000 - 3000 sq ft home with 2-4 BR could be cooled with one central AC unit - they do it all the time in Florida.  But those spit systems require a large pad outside and air handler inside.  I think it is far less expensive to go with Purifiers in every room.

.. Improvements welcome ????

Dave, been able to replace central air conditioning in most rooms in our apartment with wall units and purifiers. This works quite well for the rooms so equipped. But the last room is a large living/dining area, which still has 3 old central air conditioners which our landlord will not replace.  As soon as any of these units are turned on, the PM2.5 levels in that room immediately start to rise - so we limit their use and focus on electric fans.  Still, it can get hot. My options, as I see it, are to either replace one more more of the central units with a wall unit myself. Alternatively just get a small portable air conditioner that sits near where ever the people in that room are located.  Any thoughts on these ideas (or any others)?

[Pravda]

Absolutely disgusting today!

[MaxYakov]

1 hour ago, Pravda said:

Absolutely disgusting today!

Agreed. I believe I have a hypothesis to explain this. Remember when we got a moderate/good spell last week? The winds were southerly, coming from the Bay of Bangkok but, as opposed to today, they were coming from the west, over the Thai/Myanmar peninsula and, as I recall, there were relatively few fires on the peninsula.

 

Today, again we have the southerly winds from the Bay of Bangkok except that today they are being fed primarily from the easterly winds over south Cambodia and Vietnam and around the coast of Vietnam and Cambodia. Below, I have posted an air quality presentation from the real-time VentUSky site (second image, below). It shows not only the winds, but the pollution levels. The Bay of Bangkok is indicated to have a couple of high pollution spots - no doubt caused by intense burning in Cambodia. The FIRMS site (third image, below) indicates a high number of fires approximately at the same latitude as the Bay of Bangkok high pollution areas (second image). There are also a fairly high number of fires surrounding Bangkok (third image, below).

 

Bottom line is my hypothesis is that we're breathing, to a large degree, smoke from Cambodia and Vietnam which is being driven to Bangkok by easterly winds from the two countries which rotate to become a southerly winds over the Bay of Bangkok. This is, of course, adding to the quiescent pollution generated by fires, motor vehicles and industry (probably generating a perpetual "moderate/yellow" level)

 

 

 

[Misty]

Walking down Sukhumvit this afternoon, PM2.5 detector flashed red the whole walk, maxing out out at 160 = AQI 210

 

[DaveInSukhumvit]

On 2/24/2020 at 10:01 AM, Misty said:

Dave, been able to replace central air conditioning in most rooms in our apartment with wall units and purifiers. This works quite well for the rooms so equipped. But the last room is a large living/dining area, which still has 3 old central air conditioners which our landlord will not replace.  As soon as any of these units are turned on, the PM2.5 levels in that room immediately start to rise - so we limit their use and focus on electric fans.  Still, it can get hot. My options, as I see it, are to either replace one more more of the central units with a wall unit myself. Alternatively just get a small portable air conditioner that sits near where ever the people in that room are located.  Any thoughts on these ideas (or any others)?

Sounds like you have a big place with a lot going on.  I know the answer in the USA - air handlers usually come equipped with filters on the intake (suction) side cleaning the air before it goes into the fan aka blower.  In the US, you just put a filter in there.  If you want 4" HEPA filter, you can have AC guy rework the sheetmetal to include that larger filter.

Sorry, but I don't know much about Thai installations.  Many condos/apartments/homes I have seen are leaky.  I would start with a inexpensive meter to see how the inside air is compared with outside (with purifier running).  Sndway meter is fine, but not shipping from China right now AFIK.

[DaveInSukhumvit]

On 2/24/2020 at 8:15 AM, mtls2005 said:

AQI forecast for this week looks dismal...no clue how accurate that forecast is though.

Has anyone looked at the accuracy of these pollution forecasts, and could share an opinion?  They seem suspect to me.  As Max wrote, wind blowing East fire areas mixes with low velocity clean air from the South ocean .... and AQI suffers.   If Thursday and Friday hit Purple (~250 AQI), almost everybody starts getting sick.

I have not found a great wind forecast site yet.  I think wind forecast (velocity and direction) is key to a good pollution forecast.

[MaxYakov]

34 minutes ago, DaveInSukhumvit said:

Has anyone looked at the accuracy of these pollution forecasts, and could share an opinion?  They seem suspect to me.  As Max wrote, wind blowing East fire areas mixes with low velocity clean air from the South ocean .... and AQI suffers.   If Thursday and Friday hit Purple (~250 AQI), almost everybody starts getting sick.

I have not found a great wind forecast site yet.  I think wind forecast (velocity and direction) is key to a good pollution forecast.

I've never put any stock in the forecasts because I didn't and still don't see on what basis they are made. I've never taken the time to record the forecasts and compare them to what happened. My gut tells me that they have not been accurate just from a very cursory memory of what they were and the real-world readings. I'd love to discuss this with the forecasters (to find out what kind of darts/target they are using ????).

 

I guess that since you have pointed out Thursday and Friday, we'll see.

 

PS: I have a new set of Bangkok AQI/wind/fire readings from around midnight that seem to explain why the AQ improved late yesterday evening from Unhealthy/Red to Orange/Unhealthy for Sensitives that we're seeing today (up until 9AM anyway - it's a dynamic situation). I'll post them.

 

The wind had shifted from going directly to the west from Cambodia to sort of a wrap-around (skirting) Cambodia and Vietnam before proceeding to the north. The pollution level over the Bay of Bangkok (according to Venusky) also reflects this change.

Edited February 26, 2020 by MaxYakov

[Misty]

18 hours ago, DaveInSukhumvit said:

Sounds like you have a big place with a lot going on.  I know the answer in the USA - air handlers usually come equipped with filters on the intake (suction) side cleaning the air before it goes into the fan aka blower.  In the US, you just put a filter in there.  If you want 4" HEPA filter, you can have AC guy rework the sheetmetal to include that larger filter.

Sorry, but I don't know much about Thai installations.  Many condos/apartments/homes I have seen are leaky.  I would start with a inexpensive meter to see how the inside air is compared with outside (with purifier running).  Sndway meter is fine, but not shipping from China right now AFIK.

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.

[MaxYakov]

32 minutes 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.

My landlord replaced my dinosaur bedroom with a new, common-variety unit (balcony compressor-fan/ceiling evaporator-fan) and my electricity usage/costs dropped by at least 50%. I did some research on portable units some time back and the thing that stood out in my mind (today) was the advice that a portable unit has to have a way to divert the heat to outside the room or it won't be as effective. A cheap unit may not have the necessary hose/pipe to do this hot air diversion (if my memory serves me). Heat dissipation is why the compressor-fan component of the common-variety, refrigerant-based A/C units are placed outside.

 

PS: I've always kept my refrigerator on the balcony wherever I've lived to dissipate its generated heat to outside air rather than into my room(s). Yeah, it's a little inconvenient, but keeps my electricity costs down and my rooms cooler when the A/C is not being used (very common with me this winter).

 

I've taken a multitude of actions that people would probably not believe to keep my electricity costs down. Last month (December) my electricity was only 595 baht@5 baht/kWh (< $20 USD) and I didn't suffer much AND am breathing extremely clean air (001 PM 2.5) at the same time.

 

 

 

 

Edited February 26, 2020 by MaxYakov

[Misty]

5 hours ago, MaxYakov said:

My landlord replaced my dinosaur bedroom with a new, common-variety unit (balcony compressor-fan/ceiling evaporator-fan) and my electricity usage/costs dropped by at least 50%. I did some research on portable units some time back and the thing that stood out in my mind (today) was the advice that a portable unit has to have a way to divert the heat to outside the room or it won't be as effective. A cheap unit may not have the necessary hose/pipe to do this hot air diversion (if my memory serves me). Heat dissipation is why the compressor-fan component of the common-variety, refrigerant-based A/C units are placed outside.

 

PS: I've always kept my refrigerator on the balcony wherever I've lived to dissipate its generated heat to outside air rather than into my room(s). Yeah, it's a little inconvenient, but keeps my electricity costs down and my rooms cooler when the A/C is not being used (very common with me this winter).

 

I've taken a multitude of actions that people would probably not believe to keep my electricity costs down. Last month (December) my electricity was only 595 baht@5 baht/kWh (< $20 USD) and I didn't suffer much AND am breathing extremely clean air (001 PM 2.5) at the same time.

 

 

 

 

Thanks for this MaxYakov, very helpful. Maybe the portable unit isn't the answer here.   I wish I could get our PM 2.5 numbers down to 001 - probably our place is too big, so I remain okay with single digits during peak smog periods (but can get zero in off smog).  The exception is the big room - it's usually in the teens, and will go up to 35-ish if one of the central air con units is started up. 

 

Went to HomePro today and requested a site survey from their technicians.  My idea is to replace one of the central air units in the big room with a wall unit, and limit our use to just that one - and only when it's really hot.

[TallGuyJohninBKK]

6 hours ago, DaveInSukhumvit said:

Has anyone looked at the accuracy of these pollution forecasts, and could share an opinion?  They seem suspect to me. 

 

The current time data on AQICN.org is very good and usually up to date...

 

But whatever method they're using for their week ahead forecasts, in my experience, has not proven to be very accurate at least for Thailand/BKK....  Many many time I've looked at the predictions for the week ahead, and then the actual result has been nowhere close. This week was the same for that.

 

Now they're forecasting that Thursday and Friday in BKK will be purple / very unhealthy, even though today is shaping up as much better than the prior two days...  Haven't hit purple in BKK yet this season, AFAIK... So let's see what happens next!

 

 

 

Edited February 26, 2020 by TallGuyJohninBKK

[TallGuyJohninBKK]

6 hours ago, DaveInSukhumvit said:

Has anyone looked at the accuracy of these pollution forecasts, and could share an opinion?  They seem suspect to me.  As Max wrote, wind blowing East fire areas mixes with low velocity clean air from the South ocean .... and AQI suffers.   If Thursday and Friday hit Purple (~250 AQI), almost everybody starts getting sick.

I have not found a great wind forecast site yet.  I think wind forecast (velocity and direction) is key to a good pollution forecast.

 

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.

 

 

[TerraplaneGuy]

1 hour ago, Misty said:

... The exception is the big room - it's usually in the teens, and will go up to 35-ish if one of the central air con units is started up. 

 

Went to HomePro today and requested a site survey from their technicians.  My idea is to replace one of the central air units in the big room with a wall unit, and limit our use to just that one - and only when it's really hot.

Have you learned why using aircon increases the particle count?  Earlier in this topic I mentioned that I find whenever I use my aircon my Sndway monitor shows an increase.  I have modern Daikin units (one upper wall output for each room with compressors on the balcony) and my understanding is they aren't supposed to suck in dirty air from outside, just keep re-circulating the existing room air.  I've had the filters cleaned by Daikin recently but the problem remains.

[Misty]

11 minutes ago, TerraplaneGuy said:

Have you learned why using aircon increases the particle count?  Earlier in this topic I mentioned that I find whenever I use my aircon my Sndway monitor shows an increase.  I have modern Daikin units (one upper wall output for each room with compressors on the balcony) and my understanding is they aren't supposed to suck in dirty air from outside, just keep re-circulating the existing room air.  I've had the filters cleaned by Daikin recently but the problem remains.

Only the central air conditioner units in the big room seem to increase the particle count. They are drawing in air from above the ceiling, which has a space connected to the lift area outside of our unit and also space in the unit next door (why we sometimes smell broccoli cooking next door).  I want to close all that off and just install a wall units.

 

The wall units in my other rooms seem to lower the particle count, maybe because of filtrete paper I change regularly.

[MaxYakov]

21 minutes ago, TerraplaneGuy said:

1 hour ago, Misty said:

... The exception is the big room - it's usually in the teens, and will go up to 35-ish if one of the central air con units is started up. 

 

Went to HomePro today and requested a site survey from their technicians.  My idea is to replace one of the central air units in the big room with a wall unit, and limit our use to just that one - and only when it's really hot.

Have you learned why using aircon increases the particle count?  Earlier in this topic I mentioned that I find whenever I use my aircon my Sndway monitor shows an increase.  I have modern Daikin units (one upper wall output for each room with compressors on the balcony) and my understanding is they aren't supposed to suck in dirty air from outside, just keep re-circulating the existing room air.  I've had the filters cleaned by Daikin recently but the problem remains.

I would place money that's it's the change in humidity caused by the A/C affecting the Sndway monitor. (I would think reduction of humidity because evaporator units have a condensation water catcher and drain - typically to the balcony) a PDF article on this very subject is HERE.

 

 

 

Edited February 26, 2020 by MaxYakov

[TerraplaneGuy]

1 hour ago, MaxYakov said:

I would place money that's it's the change in humidity caused by the A/C affecting the Sndway monitor. (I would think reduction of humidity because evaporator units have a condensation water catcher and drain - typically to the balcony) a PDF article on this very subject is HERE.

 

 

 

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). 

Edited February 26, 2020 by TerraplaneGuy