Awk

got to admit this is the worse march since ive been here, hope the rains come soon my eyes and chest are hurting.

Rain.png

So, to beat that other poster to the punch, that means there is a bare 0.115 percent chance it won't rain any of those six days, and thus a 99.885 percent chance it will rain at least one of the days? Sounds like good odds to me.

Though, what is the chance that the weather forecast is 100% correct regarding the chance of rain being 60%, 70%, or 80% on those days? And how does rain or not rain one day affect the probability of rain or not rain the next day?

Although the PM10 numbers for this evening are substantially lower than the past couple days, the smog seems just as bad. Am I paranoid for thinking that now that Chiang Mai's air quality has made the headlines, the government is fudging the numbers?

Yes.

Was reading tripadvisor, CM haze....and the farangs were saying things like "pls do be so dramatic, it's not bad at all".

The folks who were saying that it's real bad were getting flamed. My gosh.....

That is because to, probably a considerable amount of people, it is not bad at all. Had I not first read about this problem on thaivisa some years ago, I too would probably have been blissfully ignorant of it. I would, like before I read about it, do hard outdoor exercise in March just as in September. It never had any mentionable short term effect on me. I had no idea it was a problem before, or could even be dangerous. I smell some burn some days, but so what.

The same is probably the case for many other people. Many people will have to actively read up on this to know there might be a problem, as they will not feel it and will think nothing special about it. Same any fog.

Unfortunately, I don't think there is any research indicating that not feeling the problem in the short term will in any way prevent you from suffering in the long term, with various respiratory diseases or even cancer. So, ignorance is not bliss in this case.

@AWK

We saw the 203 model at Robinsons at ~20k which appears suitable for our living area. Maybe quieter than the 603? Not worried about bedrooms as a/c has ioniser and reasonable dust filter.

None of the small units appear capable of good filtration in a large room, may be ok in a very small bedroom used as an air mover although a

pedestal fan is far cheaper.

I have not tried the 203 (or any other air purifier than the 650E), but yes, I'd assume it would be quieter at the same power setting. It however may well be that you while you need to run the 203 at max power, you could have run the 650 at medium power. Medium power on the 650E is comfortably quiet, while max power is annoyingly noisy.

According to the Blueair website, 203 max decibel is 56, while 650 max db is 66. 10 DB more should mean the 650E is about 10 times as loud at max power I think. So yeah, I guess the 203 would be quite a bit quieter at the max setting.

Of course, if you later on find out that even at max power, the CADR (clean air delivery rate) of the 203 is not enough to bring the pollution inside down to an acceptable level, you are SOL unless you can find another use for the 203, and then you'd still need to buy another air purifier.

In our large bedroom, which is around 80m^3 I guess, when pollution is at it's worst outside and we run 650E at max power, the pm2.5 count inside is 1/10 to 1/20 of the level outside. That pm2.5 count inside is at that time often double or even four times as much as I would have wanted however; 40,000+ outside, 3,000+, even reaching 4,000+ for periods, inside. The house we rent has poor isolation however, so things are hopefully different for you.

Most air purifiers should have a CADR rating printed on the box I'd think, so one should be able to make a meaningful comparison before buying, and you can see the Blueair 650E is rated with a CADR of 765m^3/hour on the Blueair website.

On Sunday evening at Central Festival, outside the supermarket. Air purifier sale. "Buy one, get one for free".

Agh, the silver lining in a cloud of smog.

Don't be conned, those little units do SFA.

Not sure what you mean here, captain. Do you mean those particular brands or models, or consumer range air purifiers in general?

When I was there, they did have a couple large models shown also, comparable in size to the Blueair 650E I own. And that Blueair unit works very well, I can assure anyone who wants to know. With regards to the units for sale, suggest anyone interested do their own due diligence via google, as I do not know.

I was referring to the small units one sees everywhere, priced from ~ 7k bt upwards. They do not have adequate air volume or filtration. I doubt your Blueair unit would not be available from 7k on a buy one get one free deal.

BTW: Where did you source it and how much?

Well, you might be right about that. It however obviously depends on the size of the room and how well insulated it is. E.g., in the smaller bedroom running the Blueair at speed two produces results similar to running an identical model at speed three, the max, in the other bedroom which is larger by a factor of perhaps 2.5. I'm not sure how big the difference in air pushed out is at the two settings, but judging by the noise, I would guess it is twice or thrice as much. So a smaller unit running at max speed might be enough for the smaller (3x3x3.5m?) bedroom.

I ordered the Blueairs from EAeasy (http://www.eaeasy.com/) in Nonthaburi a month or two before last years smog-season started. Ordered via email, had prompt and efficient replies in English, and delivered in Chiang Mai a few days later. Paid 35,000B each for two 650E models.

I would buy the slightly cheaper 603 model if available however. The 650E has a remote control (never used) and an "automatic" mode that is supposed to adjust the speed according to smell and dust in the room. The latter sounds very useful, but the only thing that has ever triggered the sensor is Mrs. Awk's cooking, so I quickly gave up on using that mode. Dylos Corp. also indicate on their website that most sensors in air purifiers are a somewhat of a nonsense, but unfortunately, I could not find the cheaper 603 model available in Thailand.

Here's a plot for March - May for the last four years, so anyone who wants can make their own interpretation.

My interpretation is that most years, with the exception of 2011, which was however probably also the best year, by the middle of next week pollution gradually starts decreasing. By the end of the second week of April, pm10 will in three out of the four years have fallen to below 60 ug/m^3, and mostly remain below that level. One year (2013) however still had a pm10 count above 100 ug/m^3 for most of the time till after Songkraen, due to week-lasting peaks appearing out of nowhere.

Unfortunately, the plots indicate that the decline, which will hopefully also this year start by the middle of next week, is a somewhat gradual decline. With a few setbacks included too. Since this year is the worst so far (since 2011 at least), it seems likely to me that the pm10 count will remain above 100 ug/m^3 for a long time, even if a gradual decline starts next week. Will be interesting to next week see if a decline occurs, and by how much.

On Sunday evening at Central Festival, outside the supermarket. Air purifier sale. "Buy one, get one for free".

Agh, the silver lining in a cloud of smog.

Don't be conned, those little units do SFA.

Not sure what you mean here, captain. Do you mean those particular brands or models, or consumer range air purifiers in general?

When I was there, they did have a couple large models shown also, comparable in size to the Blueair 650E I own. And that Blueair unit works very well, I can assure anyone who wants to know. With regards to the units for sale, suggest anyone interested do their own due diligence via google, as I do not know.

On Sunday evening at Central Festival, outside the supermarket. Air purifier sale. "Buy one, get one for free".

Has this happened in previous years?

Due to fly back to dmk on Wednesday morning. If I miss that flight it's going to <deleted> me over as I'll miss my international flight.

Wondering if I should take a night bus instead...?

as you stay in CM, means you like that place, !!

You should stay there and enjoy with the people !! 5555

This poster reminds me of the conversations I had with the most stupid bargirls I met on my first days in Thailand.

Thanks for bringing back some funny memories, mango66.

Has the situation improved during the last few years?

Unfortunately, one cannot claim that I think. At least not for the months February - March. Below is a plot for those months for the last four years. Shows pm10 from station 36t up to 12:00 today.

As can be seen, February this year started out with the highest pm10 count ever (counting from 2011) for February, and continued as the highest for the first half of the month. March the same; started out as the worst ever, then dropped to second worst for a few days, and is now back as the worst ever.

I have no idea if the weather forecasts with thunderstorms or rains mentioned by some will come true, but if nothing unusual happens, this looks like it will be the worst March ever. Already it is considerably worse than the previous record holder, March of 2012.

These plots have been smoothed, so some short-lasting (less than two hours I guess) bottom/top peaks will probably have been removed.

Bought a memory card at Big Camera after they said it was correct one. It wasn't, went back for a refund. The staff were adamant that I'd see pigs fly before I'd ever see a refund from Big Camera. They were right.

Another one to cross off the list then.

Similar mistake at Home Pro for that thing in the toilet that is supposed to stop more water flowing in once the tank is full enough. Mrs. Awk brought with her the old one to show staff and get the correct replacement. The one they gave her did not fit however, as the diameter of the pipe they gave her was to small. Only noticed this when installing it unfortunately, at which point the package was obviously unpacked and even dirtied slightly. I was not sure what was going to happen, but replacement, this time correct, was no problem at Home Pro.

The chart is interesting, and I can certainly understand how a good air filter will help clear up a lot of the problems indoors. But I don't understand how there can be a 50% drop indoors without one. Air still enters the house (thank God...) And the particulate matter is measured in microns, not inches or centimeters (than God...) "Micron" is a pretty small measurement. The adult human hair 'averages' about 40 microns thick. So we're talking about particulate matter far smaller than a human hair. What is it about going indoors that would drop the percentage 50%? Air is still entering. It's still circulating. I can see a small drop as the particulates cling to surfaces, perhaps a 5%-8% drop. But no where near 50%.

Afaik, there is no significant drop in indoors as far as pm2.5 is concerned. I measured this myself last year, and I also recently read some research papers confirming the same. Possibly there is some error in the measurement procedure for the plot, as I do not understand the results either. E.g., perhaps the living room is close to the bedroom, and after a while, cleaner bedroom air seeps out into the livingroom. I know that outside my closed bedroom, where I run the air purifier at max currently, the air will be somewhat better than in the rest of the house, presumably due to the same reason.

For the larger pm10 particles, I measured a notable drop by going inside however (around 30% reduction was what I measured last year).

However, the simple fact of turning on the AC, even without any extra filters, significantly reduces the pm2.5 count by up to 50%. 3M improves the reduction, but in my measurements, by a somewhat surprisingly small margin.

The main thing to do now is to switch on the AC if you have one in my opinion.

Why does just a regular old AC help? I am not sure, but I guess any filter will catch a fair amount of the pm2.5 particles also, e.g. ref. the counts posted by vivid for the surgical mask that is not intended to catch pm2.5, but which still reduces the particle count by half (or more if I remember correctly). If so, circulating the air again and again even through a regular AC filter should remove some particles each time air passes through. As long as the even slightly cleaner air coming out of the AC flows out a rate considerably larger than the more dirty air from outside flows in at, it makes sense that air inside will be at least slightly better. I was much surprised by how much better it was however.

More recently I also measured inside our newish car, which has much better isolation (I suspect) than the house we live in. With the AC off, there was no significant difference in the pm2.5 count versus outside, while pm10 was considerably lower. After running the AC at the regular speed (lowest or second to lowest, don't remember) for 15 minutes, while driving even, pm2.5 count inside was about 1/3 of the pm2.5 count outside, so as suspected considerably better than in our leaky house. Should obviously be repeated a handful of times to be sure, but I only did this particular measurement one.

Note that most car AC's have a setting for whether to just circulate the air already inside the car, or whether to let in air from outside and cool/filter that. Obviously, the former is what one wants at this time.

For anyone interested, outside the supermarket at central festival this evening there were some people selling air purifiers. Advertised as "buy one, get one free".

Were a couple different brands, though the only I had heard of was Bionaire.

Cisco Linksys is the worst modem I've owned. Broke twice. Fortunately, both times still under warranty, and Goodspeed replaced it, although the second time I had to wait several months. Convinced them to let me borrow some other modem while waiting after it started to take a while. Then the Linksys broke again. I was fooled by the Cisco name, but this product has nothing to do with Cisco's pro network gear is my suspicion.

Also lacked some rather basic features that I have never seen missing on other home modems. Staying far away from Linksys now.

The lowest PM2.5 concentration today was 72 ug/m3 @ 1600h. 2100h = PM2.5 109ug/m3.

Please do not for any instant think that 72 ug/m3 of PM2.5 is clean healthy air. It is not.

Over here in Singapore, 72 ug/m3 PM2.5 is still considered Unhealthy hazy air. 109 ug/m3 PM2.5 is definitely considered to be quite hazy. My colleagues/parents/regular joe on the street start to notice that it's hazy when it hits about 50-60 ug/m3 and start to dig for news and be mindful. Only the hardcore joggers go jogging when it's above 60ug/m3. Just to give you people another frame of reference.

I'd love to put my DC1700 next to the 36t station for some hours to calibrate it against the pm2.5 readings 36t reports. As it is, the results I get do not seem to match too well. When 36t reports pm2.5 at it's worst in the morning, e.g., numbers above 300ug/m^3, I get 30,000+ on the DC1700, perhaps up to 40,000. This matches in the sense that it's the worst I've seen.

Yet during the early afternoon, around 15:00, today, yesterday, and most other recent days, the DC1700 reports pm2.5 numbers around 3,000-4,000. 36t also reports considerably lower numbers at this time, e.g. slightly less than 100ug/m^3, though this is as you say still very unhealthy. If the relationship with 36t was linear, the DC1700 should have been reporting at least the double I'd think. This has been the case both about 5km from 36t, and 15km from 36t on all days I've checked. Any idea why this might be?

At it is, I've been using the dc1700 readings of 3,000-4,000 as an excuse to do some of my favourite outdoor exercise, which I for logistic reasons need to do around 15:00 anyway.

I have the following operating in 2 homes as my kids shutter between my parent's house and mine.

Sharp KC-840 (210 m3/hr)

Sharp -Z31 (180 m3/hr)

Sharp A28 (160 m3/hr)

Samsung AX40 (323 m3/hr)

Novita NAP501 (250 m3/hr)

LG LA-Q379SB (I think approx. 300 m3/hr)

Do you btw know if any of these have been tested regarding releasing ozone, as a by product or otherwise? I was reminded of ozone this evening when Mrs. Awk told me that perhaps it was better to just run the air purifier for half an hour or so before going to bed. The neighbour had apparently seen some program on TV that involved an air purifier, some gas (Mrs. Awk thought "ozone" sounded familiar), and a dead cat.

I comforted her by saying that I had also heard about that (ozone, not the dead cat), and that the air purifiers we had bought had been checked to not release any ozone into the room (in fact, Blueair claim it removes ozone from the room), and thus it was better to just leave them on all night.

I couldn't immediately find any reference to ozone and dead cats, but it's easy to find many references to harmful effects, including increased risk of death from very small levels of ozone, and that some air purifiers produce them. I think that might have been my main reason for buying Blueair last year; I couldn't find anything indicating that the other (and mostly, much cheaper) air purifiers availably locally had been tested with regards to releasing ozone as a by product. I think on the 2014 thread here last year somebody mentioned he had an air purifier that produced ozone intentionally (yes, that also happens), but it had a switch to enable or disable it.

Seriously, does spraying a little water in the air clean a very area?

It does clean the immediate area a little. With regards to that picture, perhaps the immediate 1 sq km. But you'd have to do that continuously as long as the levels are very high, and that means for a good half a day, every day.

I've long been curious on whether that helps. Best I could guess would be that it would only help for a very short time, perhaps by the water literally pushing the particles in the air down as the water itself falls down to the ground. You say the helpful effect is not even short time, but only while spraying. I googled before trying to find anything published that explains how this works and what the effect is, but could not find anything.

Might I thus ask from where your knowledge on this has been gained?

January last year I shopped around in CM for air purifiers. There are various price ranges of air purifiers available, from cheaper Korean brands (Samsung), or even the Chinese Hatari which I also think I saw somewhere, to more expensive stuff from Canadian Bionaire, and some European brand also if I remember correctly.

From what I read, some air purifiers give of ozone or other harmful things, so I wanted to get one that had been tested by something reputable to not do that. I'm sure I paid way over the top, but I bought Blueair, ordered from Bangkok as I could not find it locally in Chiang Mai. Phillips also had a model available in Thailand with good reviews, but the price difference was not too big compared to the comparable Blueair model I was looking at.

Basically Blueair (and IQAir, also available in Thailand I think) was in the top 3-5 of any test I found, Consumer Reports USA included, if reviewed at all. At the time I was getting very bored with spending a lot of time trying to cross-check air purifiers I could find in the various local shops here against reviews on the net, so just caved in and bought what I assumed was some of the best I could get.

After testing (with the Dylos) both 3M filtrete and the air purifier, getting an air purifier was a no-brainer for me, though that was based on efficiency only, not price. With your calculations, it looks like one of those air purifiers will be cheaper also, even in the not so long run.

The replacements for my Blueair model were 7,000B last I checked, scheduled for replacement after 180 days it says, so the calculation is a little different there.

The Blueair model I got (650) is speced for > 765m^3/hour, but even this one I have to run at the max power in the bedroom these days. Generates an awful amount of noise, which surprisingly enough does not prevent anyone from falling a sleep. Even at that setting, the Dylos reports pm2.5 readings up to 4000 now though. Still, that's a tenth of what is outside the very poorly isolated room, so it seems to be doing its job.

Hi awk,

Actually, your blueair HEPA can be replaced every 12 months or even more if you really wanna push it, even though the annual PM2.5/PM10 levels are quite high. The HEPA filter is quite a big and deep unit (3pcs total), it can certainly hold a lot of PM before noticing a drop in airflow.

The reason why blueair and some other brands recommend 6 months / 180 days is that the HEPA cleans even germ and virus sticking on aerosols in addition to pollen and mold particles. Mold particles can grow and compromise the HEPA media (just as how mold can compromise lens coatings), one compromised then secondary pollution can occur as these partculates and germs/viruses are released. But it's no a big issue, so ultimately it depends on the size of your wallet.

Wow, 650E 765m/3hr machine. Would take 2.5 units of Samsung AX40 to equal that (6200 x 2.5 = 15,500 baht).

90% cleaner than external is decent, I presume your room is at least 30 sqm and 3.5m high? Usually I get approx. 90-95% vs outside, but after 2013's PM10 of 500ug/m3 (3hrs average) and PM2.5 292 ug/m3 (24-hr), we did not get thick haze. (2014 we had haze of PM2.5 60-131 ug/m3 but lasted very long for 3 months intermittently).

Take yesterday's peak in Chiang Mai of 368 ug/m3 PM2.5 1-hr, that means you can clean it to 36 ug/m3 in your "leaky" room, which is very breatheable.

China's apolcalypse was 990 ug/m3 PM2.5, still 99 ug/m3.

In our household, I have mild allergic rhinitis but mainly my reaction to Indonesian haze = terrible headaches. I mean, I can't take paracetamol for nearly 3 months, I think my liver would be dead first.

My wife has slightly high platelet count, but still does not need any blood thining agent as she's young. But the stroke and cardiac problems risk is slightly higher than the general population. Lastly, my mother in law is on blood thinning medication called warfarin due to a cardiac issue and operation before. Hence the risk is high for her.

I have the following operating in 2 homes as my kids shutter between my parent's house and mine.

Sharp KC-840 (210 m3/hr)

Sharp -Z31 (180 m3/hr)

Sharp A28 (160 m3/hr)

Samsung AX40 (323 m3/hr)

Novita NAP501 (250 m3/hr)

LG LA-Q379SB (I think approx. 300 m3/hr)

Approx 30 pieces of replacement HEPA filters sourced from China Taobao. Cheap stuff, but still quite high in efficiency and decent airflow

5 pieces of long Velcro so that I can tape them in front of the fan, during emergency use....so that I can filter the whole house.

You can see such things on youtube (DIY HEPA) and China households. The airflow is pretty low, but it definitely works according to my wind meter + laser particle counter.

Hmm, more like 25m^3 x 3m I guess. Unfortunately, most middle-class houses in CM are of fairly poor quality, especially what concerns isolation, and we can't even shut all the 8 windows in the bedroom properly. And those that we can shut properly still leak around the edges, so no easy task for any air purifier. Probably the improvement is a little better than 90%, but almost 4,000 for the particle count inside and 40,000+ outside is the worst I can remember seeing. E.g., this morning it was around 25,000 outside, and around 1500-1600 inside, which is closer to a 95% improvement.

The Blueair is quite expensive unfortunately. If your calculation regarding your Samsung units are correct, The Blueair is more than twice as expensive for the same CADR, or at least was when I bought our units last year. If you are happy with your units, they seem to be a much better choice to recommend for most. If I need to buy additional units, I will perhaps try to find something cheaper, though I am happy with the Blueair units and it does give me some peace of mind.

I did some measurements (posted on the thread for 2014 here I think) with a similar contraption to the fan you show last year myself, using one of the 3M Filtrete variants though, and not a hepa-filter. Yes, that worked too, and if I could afford neither AC nor Air purifier, I would use it. Otherwise, too noisy.

When I had my house done a few years back I just bought the upvc ones from Global House, they were double glazed and Chinese.

You just had to check them as some were a bit dodgy, the good ones were fine and cut done noise significantly.

Same here. But I don't think they have them anymore. I really like them. Cut the noise and heat. The problem with the Thai-made ones is that for my house, the Chinese windows cost around 100,000 baht. The same windows made here, and I checked with all the companies I could find (including Windsor), cost 500-600,000 baht! Are they better quality? I don't know, but I simply couldn't afford to throw down an extra half million.

If I had it to do again, I order them directly from China. No way would I pay for the Thai version.

I put in four sectional garage doors all with remote openers. The price for this in Thailand? 500,000 baht. I was shocked at this outrage so started investigating China (the Thai doors are imported from China, too). I got a high quality set of doors with remote openers from China for 50,000 baht and am completely satisfied! I also bought galvanized and powder coated welded wire fencing from China for half what I would have paid here. Again, high quality and totally satisfied!

I don't know what it is with certain Thai vendors of the higher end products. it seems they think they need to have 200-300% profit. Not from me. There are always other ways, if you are not too risk averse.

How do you go about ordering large things like this from outside Thailand? Perhaps you could post the urls of some shops in China you were happy with also?

Awk if you read carefully on that link on wikipedia it is 3.3micro second not millisecond(ms) micro is in millions comparing to milli which is in thousands very big difference. I am super happy with Sinet for one it has never gone down for me besides when the power is out. as well the speed has been super exceptional comparing to what I got with 3BB and true their service were garbage when I was in bangkok to start I never got close to stable connection to watch tv in standard definition and would drop all the time, our calls with skype overseas would disconnect half way through every few minutes. Furthermore their service team would not help us with anything since they told us it was older technology and had limitations all we could do is reboot our modem every few hours and hope for the best. Oh did I mention when internet went down we would have to wait for days upto weeks to get it fixed( they expect you to pay even with the downage) NO MORE having to deal with these problems with Sinet at less then what I paid before. Cheers do yourself a favour and avoid the hassles we had to go through. get Sinet from get go

Many thanks for all the tests. The latency results are so impressive that I unfortunately am certain that due to the silly way speedtest tests "ping" latency, the latency tests have been caught by a local Sinet proxy. So speedtest has instead of testing the latency to far away places, tested the latency to some local Sinet web proxy. :-(

Unfortunately, I'm not aware of any other website similar to speedtest that has a similar range of global servers available and which is does a better job at testing latency. :-/

I see something called http://www.pingtest.net/, but I am unable to run it on my particular computer so not sure how that works.

Download/Upload speed reported is correct I assume however, so thanks again.

Well, the isp is not really trying to fake anything. It is common for ISPs to install web proxies/caches that their customers can use, transparently or not. This is done with the intent of improving things for both the customer and the ISP, rather than to fake anything. Unfortunately the latency test implemented by speedtest.net does not seem to handle this well.

Getting sub-30ms latency to Europe, as the tests you pasted report, is physically impossible. At speed of light speed, you get a delay of roughly 3ms per 1000km (https://en.wikipedia.org/wiki/Latency_%28engineering%29). Europe is about 10,000km away from Thailand, so the delay to Europe would be about 30ms, if you had speed of light. Double that delay, as the reported latency is round-trip time (i.e., Thailand to Europe, and back from Europe to Thailand), and you have 60ms. And that's speed of light from your computer all the way to Europe and back. So I hope you pardon my scepticism regarding the latency results, and do not take offence. I suspect what most people are interested in are upload/download bandwidth anyway.

True, but that is 3.3 us (microseconds) per km. So multiply both by 1000, and you get the 3.3ms per 1000 km I talk about.

But good to hear you are happy with Sinet. I might switch to them at some point.

BTW, are HEPA air purifiers difficult to buy or expensive in Chiang Mai?

Since the haze seems to be quite a long drawn "battle" on a yearly basis, I think it'd be cheaper and more effective/useful to just get an air purifier. I have like 9 boxes of 3M aircon Filtrete that I have gotten from Amazon. They don't last more than 2-3 weeks in my aircon and that's in clean air here in Singapore during the non-hazy months. Someone used it during the hazy days last time and he said you can discard it after 3-4 days.

I have a laser particle counter that displays both mass and particles per L, with an air purifier that's properly sized, I can get an ambient of PM2.5 40ug/m3 down to 0 in my bedroom within half an hour.

Eg, I got my Samsung AX40 air purifier direct from Korea, it's like 6200 baht inclusive of shipping. 323m3/hr machine, 34W, 45dB noise that's great for light sleepers. A Sharp A28 costs 2300 baht only.

I use HEPA filters from China as replacements, they are pretty ok....like about 95-98% efficient @ 0.3 microns. About 230 - 460 baht per piece. I source them from taobao, the Chinese equivalent of Ebay/Amazon.

January last year I shopped around in CM for air purifiers. There are various price ranges of air purifiers available, from cheaper Korean brands (Samsung), or even the Chinese Hatari which I also think I saw somewhere, to more expensive stuff from Canadian Bionaire, and some European brand also if I remember correctly.

From what I read, some air purifiers give of ozone or other harmful things, so I wanted to get one that had been tested by something reputable to not do that. I'm sure I paid way over the top, but I bought Blueair, ordered from Bangkok as I could not find it locally in Chiang Mai. Phillips also had a model available in Thailand with good reviews, but the price difference was not too big compared to the comparable Blueair model I was looking at.

Basically Blueair (and IQAir, also available in Thailand I think) was in the top 3-5 of any test I found, Consumer Reports USA included, if reviewed at all. At the time I was getting very bored with spending a lot of time trying to cross-check air purifiers I could find in the various local shops here against reviews on the net, so just caved in and bought what I assumed was some of the best I could get.

After testing (with the Dylos) both 3M filtrete and the air purifier, getting an air purifier was a no-brainer for me, though that was based on efficiency only, not price. With your calculations, it looks like one of those air purifiers will be cheaper also, even in the not so long run.

The replacements for my Blueair model were 7,000B last I checked, scheduled for replacement after 180 days it says, so the calculation is a little different there.

The Blueair model I got (650) is speced for > 765m^3/hour, but even this one I have to run at the max power in the bedroom these days. Generates an awful amount of noise, which surprisingly enough does not prevent anyone from falling a sleep. Even at that setting, the Dylos reports pm2.5 readings up to 4000 now though. Still, that's a tenth of what is outside the very poorly isolated room, so it seems to be doing its job.

For those who are lucky to get hold of and afford N95s, FFP-1, KN90, whatever....pls do a proper test-fit. It's the same thing you'd do in a lab or healthcare setting. No proper test fit or care to ensure nearly zero bypass = nearly useless. Technically, you are not supposed to use it for more than a day. But I guess if stocks are low, you can push it to 2 days. It's an electrostatic filter element inside, once it's wet (eg due to human breath with many hours of usage), it's a goner.

Video showing how to wear a N95 properly.

https://www.youtube.com/watch?v=Ul9nbpyPgIw

My personal favourite is the 9210 and 9211 (with exhaust valve). It fits most people almost perfectly due to its soft design. It's also foldable, so it's really convenient to bring it out where it matters most.

The 8210 "turtle shell" actually has 3 sizes, if you are a lady with a small face and you got the large sized 8210, you are as good as not wearing anything due to the horrible amounts of bypass. For older children, you can go for the 1860S or 8110S.

The issue of bypass is very common when N95s are worn by the lay person on the street.

Any decent masks to recommend that can be used for a longer time? I've occasionally been dumping a 3M N95 on a friendly guy who works outside, but if there's something better (basically, more long-lasting, reusable in some way) that is not too expensive or scary looking, I'd perhaps buy that

for him instead next time.

Member Johnsjourney posted an interesting observation regarding how the pollution level seems to fall quite regularly during each day, thought at the time he posted, we were only a few days into March and he thus did not have so much data available. I updated with data from the aqmthai-site (station 36t), and generated plots similar to what Johnsjourney originally did. These plots show the data from March 1 till 17:00 today (March 10), though I did not smooth the curves like I suspect Johnsjourney did.

As one can see from both the pm10 and the pm2.5 plots, each day the pm-level still falls rapidly in the late morning, remains fairly low for a few hours, and then starts to raise again. Looking at the pm2.5 plot, on most days, the pm level starts to fall at around 12:00 (which means, the average pm-level since time 11:00 has been falling), and is relatively low in the period 15:00 - 17:00 on the graphs.

It is interesting that there is such a clear trend with the pm-levels raising and falling. The aqmthai site (which is pretty damn good, ignorant Thai-bashers not withstanding) also has data for temperature and windstrength (ws), as well as other things I have no idea what is. So I fetched data for some ws and temperature also for the same period. One can then put the different plots underneath each other to see if one can visualize any correlation.

The plot for windstrength (ws) shows a somewhat inverse relation to the pm2.5 plot for part of the time. At around 12:00, ws increases, and remains relatively strong till 16:00, at which the ws starts dropping again. The ws seems to vary quite a bit however, going up and down by a large amount, while the pm-level is mostly constantly going up or down, so I cannot see a good correlation. On both the pm-graph and the windstrength-graph, something does seem to happen each day at around noon however, so presumably there is some relation, though it is impossible to say that one causes the other for me.

The plot for temperature is very regular, much more regular than the pm2.5 plot. As one sees on the pm2.5 plot, there is some variability regarding both when the level starts to fall, and how fast it falls, while this is not present on the temperature graph as far as I can see.

It is difficult to see on the plot, but on day 01, pm2.5 started dropping two hours later than the other days. On this day, the temperature also started out at it's lowest, at 24.5 degrees, and remained lower than for the other days at least until in the afternoon. On this day, the temperature of 38 degrees was also reached two hours later than on the other days.

Have to admit all of the above speculation is very much bush league however, so just thinking a loud here. Perhaps somebody else has some other ideas. It does look to me that the time 14:00 - 16:00 (real time, not the one hour delay on the graphs), or better, 15:00 - 16:00, is generally the least bad time time of day, however. Also not just by a little bit, but by a large factor the best time of day.

pm2.5-raw.pdf

pm10-raw.pdf

temp.pdf

ws.pdf

The links below would give you a very good idea how long the haze is gonna last. Currently Thailand and surrounding countries are just absolutely dry.

Interesting. So, how long is the haze gonna last?

One hour ago: pm 2.5:30,000+ outside the bedroom, same as outside the house.

Inside bedroom, with air purifier at max, and ac running too: 3,000.

Don't suppose we could stay with you guys for a couple weeks?

Seriously though, I'm getting rather worried, as the windows in my apartment don't shut that firmly and my AC (which I never use) is old. Does anyone think it would work, if I could fit it with filters, to purify the air in my place somewhat?

Now: close to 4,000 in bedroom, almost 40,000 outside bedroom, above 40,000 outside house.

In my amateur analysis last year I tested with an old AC and a poorly constructrd house with windows that do not shut tight (same house we still rent). Running the ac with standard filters helps a fair amount. 3M filtrete helps a little more.

<script type='text/javascript'>window.mod_pagespeed_start = Number(new Date());</script>

But PM10 only 93 and 'Moderate' at City Hall this morning. That's ok then...... But I have never known humid mist smell so smokey 555

I think I've been using the same app as you beau thai... think it's broken, eh.

Yep, same here. I think they must have a sprinkler in front of the equipment....

Don't join that particular tin foil wearing hat brigade over this. The AQICN (Air Quality In ChiNa, is my guess) shows 114 you say.

Well, if you add this numbers, from the aqmthai site (which I guess is the official Thai site, and from where I suspect aqicn gets its data), you will also get 114:

79.42

61.46

53.69

67.13

94.78

102.57

136.36

152.08

147.75

147.86

156.07

170.51

181.75

165.29

187.38

187.83

186.59

234.65

282.83

342.90

331.47

302.74

336.38

252.44

The sum of that 24 hour period, starting March 14:00, is 4361. The average is 182. Input 182 into "http://www.airnow.gov/index.cfm?action=resources.conc_aqi_calc" and you will get an AQI of 114.

I thought I read somewhere that the AQI is supposed to use other factors than only the pm10 or pm2.5 also, but either I remember wrong, or neither the aqicn-site nor the airnow-calculator does bother itself with that. Perhaps the other factors are not so important.

This also means, unfortunately, that the aqicn-site is useless for any type of real-time behavioral adjustment. Better use the (official?) Thai site, aqmthai (Air Quality Muang Thai?), for that, which reports the average of every past hour I think.