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BANGKOK 19 May 2019 13:35

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Tywais

Smoke, Smog, Dust 2015 Chiang Mai

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I, mostly out of curiosity, check the pm2.5 reading of my DC1700 particle counter in the evening. Then I decide whether to switch on the air purifier or not, and at what level; medium or max level. Then, being curious, I check things again in the morning, after the air purifier has run all night. Been doing this since the middle of January.

For reference, the Dylos Corp. has this printed on the DC1700, referring to the number (not the mass) of pm2.5 particles reported.

3000 and above = Very Poor

1050-3000 = Poor

300-1050 = Fair

150-300 = Good

75-150 = Very Good

0-75 = Excellent

There is no good mapping to the standard, mass-based, pm2.5 metric as far as I know, but the above are Dylos Corp's guidelines (not sure what they are based on).

You can read more about Dylos corp's products here: http://www.dylosproducts.com/

Anyway, up until 3-4 weeks ago, the pm2.5 reading had been around 2,000-3,000 most of the time. Sometimes down to around 1,000 also. That's the level it is at much of the year I think, though I have not really attempted to verify that. So I have not bothered running the air purifiers at that time. Then the pm2.5 count started to raise, and most of this month I think it has been around 4-7,000 in the evening, before I switch on the air purifier.

So I've been running the air purifier at medium power most of the nights this month, increasing to the max when the reading was above 6-7,000. There's been some days where it has been close to 10,000. Medium power on my air purifier (Blueair 650E) brings the pm2.5 reading down from 6-7,000 to around 2-3,000. Not great, according to Dylos Corp's guidelines, but in honesty, I am not sure how applicable they are. If I remember, I will try to bring the DC1700 with me next time I leave for work, which it currently looks like will be to one of the supposedly cleanest countries (pollution-wise) in the world, to see what the DC1700 reports there. If the pm2.5 reading is much higher than 6-7,000 the evening before, I need to run the air purifier at max power to bring the pm2.5 reading in the room down to 2-3,000. If run at max power, most of the time, the pm2.5 reading will then be around 1,000 in the morning. But max power generates a lot of noise.

Last night I came home late (Friday night, you know). Mrs. Awk had switched on the air purifier at medium power, and I out of curiosity checked the pm2.5 reading before going to bed. I saw that it was around 6-7000, and since the air purifier was running at medium power, I switched it up to max power, waking up Mrs. Awk in the process.

When I woke up this morning, after running the purifier at max power all night I however saw that the pm2.5 reading was still around 5,000. I thought this was quite strange. I walked around checking if Mrs. Awk had for some reason opened a window or or two, but no. Then I thought maybe I had placed the air purifier at a somewhat stupid location, close to the wall (to reduce the chance of baby-Awk running into it). So I moved it to the middle of the room, and checked the pm2.5 reading again after an hour. Nope, still around 5,000. Then I took my dc1700 outside the room. Outside the room, the pm2.5 reading was almost 20,000, perhaps even above that for some periods.

Indeed, it does appear that it, whatever it is, it has arrived.

Thanks for posting this info, and it confirms my fears that CM air quality is poor year round (PM 2.5 1000 is your estimate).

Every time I leave, I notice the cleaner air, no matter where I go.

Oh, no no no. Please read again what I said carefully. The pm2.5 number I mention of 1000 is not the microgram/m^3 that is used in most other places, but the number of particles the Dylos reported. It has no direct relation to the health standards for pm2.5 and represents something very different. 1000, if reported by the Dylos device, is "good air".

But in the table you provide 1050-3000 is considered poor. And this refers to the number of particles report by Dylos, does it not?

I figured 1000 is close to 1050.

I did not think it referred to micrograms/m^3.

From your table, good air is 150-300, again the number of particles reported by Dylos. 1000 would be at the high end of the fair reading

What am I missing?

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I, mostly out of curiosity, check the pm2.5 reading of my DC1700 particle counter in the evening. Then I decide whether to switch on the air purifier or not, and at what level; medium or max level. Then, being curious, I check things again in the morning, after the air purifier has run all night. Been doing this since the middle of January.

For reference, the Dylos Corp. has this printed on the DC1700, referring to the number (not the mass) of pm2.5 particles reported.

3000 and above = Very Poor

1050-3000 = Poor

300-1050 = Fair

150-300 = Good

75-150 = Very Good

0-75 = Excellent

There is no good mapping to the standard, mass-based, pm2.5 metric as far as I know, but the above are Dylos Corp's guidelines (not sure what they are based on).

You can read more about Dylos corp's products here: http://www.dylosproducts.com/

Anyway, up until 3-4 weeks ago, the pm2.5 reading had been around 2,000-3,000 most of the time. Sometimes down to around 1,000 also. That's the level it is at much of the year I think, though I have not really attempted to verify that. So I have not bothered running the air purifiers at that time. Then the pm2.5 count started to raise, and most of this month I think it has been around 4-7,000 in the evening, before I switch on the air purifier.

So I've been running the air purifier at medium power most of the nights this month, increasing to the max when the reading was above 6-7,000. There's been some days where it has been close to 10,000. Medium power on my air purifier (Blueair 650E) brings the pm2.5 reading down from 6-7,000 to around 2-3,000. Not great, according to Dylos Corp's guidelines, but in honesty, I am not sure how applicable they are. If I remember, I will try to bring the DC1700 with me next time I leave for work, which it currently looks like will be to one of the supposedly cleanest countries (pollution-wise) in the world, to see what the DC1700 reports there. If the pm2.5 reading is much higher than 6-7,000 the evening before, I need to run the air purifier at max power to bring the pm2.5 reading in the room down to 2-3,000. If run at max power, most of the time, the pm2.5 reading will then be around 1,000 in the morning. But max power generates a lot of noise.

Last night I came home late (Friday night, you know). Mrs. Awk had switched on the air purifier at medium power, and I out of curiosity checked the pm2.5 reading before going to bed. I saw that it was around 6-7000, and since the air purifier was running at medium power, I switched it up to max power, waking up Mrs. Awk in the process.

When I woke up this morning, after running the purifier at max power all night I however saw that the pm2.5 reading was still around 5,000. I thought this was quite strange. I walked around checking if Mrs. Awk had for some reason opened a window or or two, but no. Then I thought maybe I had placed the air purifier at a somewhat stupid location, close to the wall (to reduce the chance of baby-Awk running into it). So I moved it to the middle of the room, and checked the pm2.5 reading again after an hour. Nope, still around 5,000. Then I took my dc1700 outside the room. Outside the room, the pm2.5 reading was almost 20,000, perhaps even above that for some periods.

Indeed, it does appear that it, whatever it is, it has arrived.

Thanks for posting this info, and it confirms my fears that CM air quality is poor year round (PM 2.5 1000 is your estimate).

Every time I leave, I notice the cleaner air, no matter where I go.

Oh, no no no. Please read again what I said carefully. The pm2.5 number I mention of 1000 is not the microgram/m^3 that is used in most other places, but the number of particles the Dylos reported. It has no direct relation to the health standards for pm2.5 and represents something very different. 1000, if reported by the Dylos device, is "good air".

But in the table you provide 1050-3000 is considered poor. And this refers to the number of particles report by Dylos, does it not?

I did not think it referred to micrograms/m^3.

From your table, good air is 150-300, again the number of particles reported by Dylos.

Sorry, I misunderstood you then. Yes, what you say is correct, and yes, that is according to Dylos Corp's guidelines.

However:

In honesty I am as said not sure how applicable those guidelines are. I suspect they are quite a bit to strict for normal home use. If one googles,. one sees that even in California people report a pm2.5 count inside above 1000. I've gotten very used to thinking that anything close to 1,000 inside is good, though I should not have said that above since I do not know, and realize now it was a bit stupid. So again, sorry. My mistake.

I would put more faith in the government monitoring stations and the (WHO-based?) pm2.5 and pm10 standards for this.

Most of the year, the pm10 reported for Chiang Mai is afaik pretty good (there was another fellow here, Priceless, that seemed to keep good track of that, though I have not seen anything from him for a while now).

It will be interesting to see if the pm2.5 values will be similarly good, now that they seem to be available from at least one monitoring station here in CM.

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I noticed the ug/m3 readings have a daily cycle, except today unusually high most of the day.

AQI is much smoother because it averages over 24 hours, so this detail is missed.

Here's a graph of the past few days, so it seems the best time to get stuff done outside is around 12pm-7pm. The readings come in an hour or two delayed so this info isn't available real time.

I'm assuming unscientifically that inside the house is safer, just seems much fresher air inside.

The bottom axis is time.

Thanks for that graph. I have also noticed that there seems to be semi-regular pattern, so it was to nice to see several days graphed together like that. I can only wonder what causes it, as looking at your graphs, it seems strangely regular.

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I noticed the ug/m3 readings have a daily cycle, except today unusually high most of the day.

AQI is much smoother because it averages over 24 hours, so this detail is missed.

Here's a graph of the past few days, so it seems the best time to get stuff done outside is around 12pm-7pm. The readings come in an hour or two delayed so this info isn't available real time.

I'm assuming unscientifically that inside the house is safer, just seems much fresher air inside.

The bottom axis is time.

Thanks for that graph. I have also noticed that there seems to be semi-regular pattern, so it was to nice to see several days graphed together like that. I can only wonder what causes it, as looking at your graphs, it seems strangely regular.

It's even clearer with this PM2.5 one below.

From http://aqicn.org/city/thailand/chiangmai/yupparaj-wittayalai-school/m/ this week as the temperature rises the pressure falls and the wind rises, perhaps taking some of the smoke high enough in the air streams to get carried away. The wind fits the 10am-2pm period where the levels are decreasing. Today was the least windy and the highest PM levels, but if burning increases there's unlikely to be enough wind to compensate for that. I also guess from this graph the local farmers are getting up at 6am for a session of burning, and so this makes me feel most of the problem is local rather than far away.

post-13135-0-92627100-1425234284_thumb.p

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JJ...Lived in the middle of the burning for several years and have watched them lighting the fires. Generally the fires are set in late afternoon or into the evening, but I have run into people setting fires on my early morning bike rides as well. (I've posted photos taken at night showing the fire lines in the mountains as the locals set them. You can see them well at night in the early season but later on, smoke obscures those views.) The fires smoulder all night and the cooling night air slowly brings the smoke into the valleys. That could match up with the trends you have plotted. After the sun comes up, I think there is enough thermal energy for the winds to kick up to start dispersing the particulates in the afternoon.

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I agree, burning is not typically an early morning sport, most often it takes place in the afternoon or evening hence the uptick in the graph (post 109) at 6 am is more likely to be caused by the effect of sunrise and thermals - it is inappropriate to conclude the source of burning (local or distant) from that graph.

My interpretation of probable events depicted in that graph are as follows:

Late afternoon/early evening, local burning takes place and this continues into late evening - pollution levels increase as a result but cooler night air at all altitudes allows the smoke to disperse.

At 6 am the sun rises and the air begins to heat up but the inversion layer traps the polluted cooler air which accumulates closer to the ground. This continues until around midday when the heat from the sun becomes so intense as to warm the cooler air and the inversion effect is negated and the polluted air disperses more naturally and so the cycle repeats. Evidence in part to support the above is the early morning fog in the mountains close to where I live.

"Given enough pressure, the normal vertical temperature gradient is inverted such that the air is colder near the surface of the Earth. This can occur when, for example, a warmer, less-dense air mass moves over a cooler, denser air mass. This type of inversion occurs in the vicinity of warm fronts, and also in areas of oceanic upwelling such as along the California coast in the United States. With sufficient humidity in the cooler layer, fog is typically present below the inversion cap. An inversion is also produced whenever radiation from the surface of the earth exceeds the amount of radiation received from the sun, which commonly occurs at night, or during the winter when the angle of the sun is very low in the sky. This effect is virtually confined to land regions as the ocean retains heat far longer. In the polar regions during winter, inversions are nearly always present over land.

A warmer air mass moving over a cooler one can "shut off" any convection which may be present in the cooler air mass. This is known as a capping inversion"

http://en.wikipedia.org/wiki/Inversion_%28meteorology%29

As for the source of pollution, imported or home grown, one would need to look at a combination of wind and fire maps to conclude more accurately. From memory, winds at this time of year are from the south west bringing with them the polluted residue from burning in Myanmar.

.

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It's officially started now - smoke smell in the air since March 1st and Air4Thai app read 170 for PM10 this morning. That's an averaged value so the peaks are way higher.

Up in Pai burning of mountain sides has been going on for 2-3 weeks now.

Planning my escape now, just have to wait for schools to close.

As for theories there is a shockingly simple conclusion: People are burning shit. Lots and lots of people are burning lots and lots of things. From the neighbors setting a small pile of moist leaves on fire - just for the heck of it, it seems - to the villagers burning up mountainsides, everyone in this country is doing their part. The NASA fire maps are very useful but they only capture massive fires. Anything on the NASA map is an unusually large fire and I guess those in Thailand must be in remote areas or the locals would take care of it.

BTW as bad as this is, I am not sure it can change. Let's say locals suddenly stopped burning the forests. That seems like a remote possibility right now. But even if they did, there would then be huge forest fires every couple of years instead. See California, Australia. The controlled burns the locals are doing never get out of control. I've actually seen locals dousing the flames, and I was amazed. I was at a friend's house in Pai, next to the forest. We noticed flames coming closer, and didn't know what to do. The entire forest front was on fire at some point with flames maybe 2 - 3 meters high. As we stood there wondering whether the flames would engulf the house, two little old ladies appeared. Each carried a small bucket. They dipped their hands into the bucket, and were sort of flinging a spray of water from their hands into the flames. The flames went down right away... not exactly the fire trucks and power hoses I had imagined... Pai didn't use to have a fire station until a few years ago. Not saying the burning is good but I think it's important to take a holistic view of it.

As for what you can do there's groups organizing every year. There is talk of a silent protest at Ta Pae gate of groups with air filter masks on. I think that could go a long way. It doesn't take much to make this kind of thing go viral.

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Out of interest, where are those planning an escape going to, and how long do you plan to be away?

I only ask, because year after year I've sort of planned to go south... perhaps to one of the islands, but have never quite made it. Just too many commiments to be able to leave for that amount of time. I realise the answer could be just about ANYWHERE other than here, LOL but I'm interested in what others do to 'escape' and when you envisage on coming back.

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Out of interest, where are those planning an escape going to, and how long do you plan to be away?

We've done Hua Hin (within driving distance, 10 hours later you're there), Samui (direct flights even if they're really expensive), Phuket (flights), Ko Chang.

Important criteria: Needs to be on the ocean. All inland places are just as polluted as up here.

We usually come back at or around Songkran, April 15th. The last 2 years that's when the first rains fell, and air improves quickly after that. Not immediately, but in a week or two.

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Code Red

Again today in Chaingmai a huge warning for pollution code Yellow which stand for unhealthy and it slowely goes to code red very unhealthy .

Its adviced to stay in the house and not to do any heavy activity .. my god its 2015 ...

Why is the government not in power to tackle this problem ....

how dificult is it to work together with the land office and the poojabaan .

the land office now excaly who is the owner of the land wich can be fined with lets say 10.000 bht per rai they burn , the poojabaan is the end responsible and have to eductated the people not to burn there riced field He can be cut with the money from bangkok if he fail .

In my opinion this whole problem can be solved on a saterday afternoon , so why take this so long and why so many people have to suffer with health problems , not to mention the tourist industrie

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Out of interest, where are those planning an escape going to, and how long do you plan to be away?

I only ask, because year after year I've sort of planned to go south... perhaps to one of the islands, but have never quite made it. Just too many commiments to be able to leave for that amount of time. I realise the answer could be just about ANYWHERE other than here, LOL but I'm interested in what others do to 'escape' and when you envisage on coming back.

Anywhere along the Andaman Sea coastal region, except Phuket other than when absolutely necessary, until Songkran is well over. Have had sun and clean air every day since arriving mid January.

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Gas Attack?

It's getting bad here, waking up through the night coughing and sneezing.

I'm told there's a guy wandering the streets of Chiang Mai with a full mask, as used in gas attacks.

must be a sight to see. any photos?

post-111567-0-20398800-1425274887_thumb.

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Since PM<2.5 reports are now made at Site 36T, out of curiosity, I compared them with PM<10 reports since 1 February. The smaller particules were roughly 75 - 80% of the larger ones. That is bad news.

If I recall previous research (posted on this topic last year) correctly, a relatively higher proportion of the PM<2.5 is present in rice straw smoke than in general pollution which is "commonly acknowledged" as 40-60%. The smaller particles, of course, are the really insidious ones damaging to health, as people have come to realize.

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http://www.chiangmaicitynews.com/news.php?id=4872

Levels in the city seem to be getting worse over the years, although it has always been bad in Chiang Rai and Mae Hong Son. Traffic deaths are rather obvious but nothing is done in that court so doubtful any enforcement will occur on the forest burning. Mai Pen Rai and carry on.

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