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BANGKOK 27 May 2019 10:23

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Tywais

Smoke, Smog, Dust 2015 Chiang Mai

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Comparisons of readings of anything, over a five day period, do not indicate trend or much else!

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This was just a day break as they were busy celebrating Buddha day as certain as the sunrises everyday you will cough tomorrow again - and full force until rains shows mercy with us

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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.

That is some rather nice graphs. If there is a fairly predictable time of day when it is less bad to be out and perhaps exercising, that is interesting I thought.

I have been wondering whether the trend your graphs show was present over a larger range of days, and finally got around to check that. The first plot I attach is pm10 for all years I could get data for (end of 2010 till present date), and shows the month of February during those years (2011 - 2015). In total there were 3833 measurements for February during those years, and each measurement represents a point on the graph.

I.e., if the there are 10 points for the time "4", that means measurements were available for hour 04 at 10 different days in February. I don't know why many measurements are missing from the data available from the aqmthai website . Perhaps the monitoring station has some reliability issues.

The trend is not as obvious as in your graph, but can still be seen, even over five years. Plotting February separately for each year, there seems to be some small variance in when the pm10 level starts to raise from year to year, but in all graphs, it seems to be falling at 14:00. As I understand it, and as I think you say, the measurements show the average of the past hour. So if the pm10 level is shown as falling at 14:00, it probably means it started to fall at 13:00 or a little later.

Year 2011 and this year seem to show the trend especially clear, while other years less so.

I attach similar graphs for the month of March also. For that month, year 2011 also shows the trend especially clear, so perhaps this March will also continue to show the same trend. For March this year, the measurements are up to midnight March 5.

I just finished generating the graph and have no conclusion to draw, at least not at the moment. I am not sure any interesting conclusion can be drawn, but perhaps somebody smarter will see something, so I thought I might as well upload them since I had already generated them.

month-02_pm10-by-hour.pdf

month-02_pm10-by-hour.pdf

month-02_pm10-by-hour.pdf

month-02_pm10-by-hour.pdf

month-02_pm10-by-hour.pdf

month-02_pm10-by-hour.pdf

month-03_pm10-by-hour.pdf

month-03_pm10-by-hour.pdf

month-03_pm10-by-hour.pdf

month-03_pm10-by-hour.pdf

month-03_pm10-by-hour.pdf

month-03_pm10-by-hour.pdf

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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.

Using the Dylos DC1700 I did some amateur measurements last year, including evaluating the effect of being inside, versus being outside. I posted the PDF resulting from my amateur analysis here on thaivisa for anyone interested, but just to recap that part:

- There are about 30% fewer particles with the a size above pm2.5 inside, compared to outside. I.e., as far as pm10 is concerned, it is quite a bit better to be inside.

- There is no significant differences between inside and outside for particles smaller than pm2.5. Unfortunately, pm2.5 is, most now seem to think, the main hazard, and being inside does not help. What does help is running an AC, with or without 3M Filtrete, or better, an air purifier. Best: AC and air purifier.

Based on the trend your graphs showed, I had some worries, and therefore did some more measurements with the dc1700 the past few days. Both this Friday and last Wednesday, air downstairs inside the house (the living room, where no air purifier runs during the evening/night) was considerably worse in the morning than the air outside. The particle count inside was close to 10,000, while outside it was roughly half of that. These measurements were done around 11:00 in the morning.

I wonder if one explanation might be that improvements in air quality outside is related to temperature, though I will not at the moment hazard to guess exactly how. Outside at 11:00, it's quite hot, and if this causes the pollution to go away (perhaps by the polluted air heating and, at least temporarily, raising?), this effect may not be equally present inside the house, where is is much cooler than outside.

After a while, the pm2.5 count inside and outside is fairly close (at least for the poorly constructed house we live in), but this can take quite a few hours, and might depend on wind conditions too. I tried ventilating by opening the two doors downstairs to the outside, but could not measure any significant improvements. I wonder if placing a fan outside the door, blowing air in, will have a more measurable effect and more quickly bring the indoor air quality to a level similar to the outside.

Instead I carry the air purifiers down from the upstairs bedrooms, both of them, as only one has little effect on the large downstairs living room, but even both air purifiers running at max power use several hours to lower the particle count considerably. Perhaps placing a fan in the doorway first,

before closing the doors and switching on the air purifiers, will make the process faster. Will try that next time.

Well, that was Wednesday and Friday morning. On Thursday morning, there was for some reason no big difference between the inside and outside. I see now that according to the aqmthai, the pm 2.5 count was considerably lower on Thursday morning than on Wednesday and Friday morning, so perhaps it is somehow related to that.

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I thought it worthwhile posting the link here since so few posters understand that much of the pollution we experience in the North currently is imported from the South West, from Myanmar:

http://www.windfinder.com/weather-maps/report/thailand#6/19.456/97.251

Doubting Thomas's may wish to review the forecast.

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I thought it worthwhile posting the link here since so few posters understand that much of the pollution we experience in the North currently is imported from the South West, from Myanmar:

http://www.windfinder.com/weather-maps/report/thailand#6/19.456/97.251

Doubting Thomas's may wish to review the forecast.

A week ago when this all kicked off, I was at the top of Doi Suthep & around 9.30am the views south & west were the clearest I've ever seen them. The view east was looking down on a sea of smoke. By 10.30am the smoke had risen to Wat Doi Suthep level. Down at city level visibility was very poor. This smoke is generated locally. If it had come from Burma, they must have smuggled it in container trucks or there's a pipeline.

When there's wind, the smoke clears, it doesn't arrive.

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Reminder of this forum rule, one post removed.

26) The Bangkok Post and Phuketwan do not allow quotes from their news articles or other material to appear on Thaivisa.com. Neither do they allow links to their publications. Posts from members containing quotes from or links to Bangkok Post or Phuketwan publications will be deleted from the forum.

These restrictions are put in place by the above publications, not Thaivisa.com

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I thought it worthwhile posting the link here since so few posters understand that much of the pollution we experience in the North currently is imported from the South West, from Myanmar:

http://www.windfinder.com/weather-maps/report/thailand#6/19.456/97.251

Doubting Thomas's may wish to review the forecast.

A week ago when this all kicked off, I was at the top of Doi Suthep & around 9.30am the views south & west were the clearest I've ever seen them. The view east was looking down on a sea of smoke. By 10.30am the smoke had risen to Wat Doi Suthep level. Down at city level visibility was very poor. This smoke is generated locally. If it had come from Burma, they must have smuggled it in container trucks or there's a pipeline.

When there's wind, the smoke clears, it doesn't arrive.

I think there was one year where the winds from the north did seem to bring in more smoke, but you are right that the great majority of the particulates this season are locally generated. If the winds pop up , as they did around noon today, you can see the fast drop in the PM10 levels. Don't see how it could be smoke from Myanmar if the 5-10 MPH winds can disburse it so quickly. Things will be the same next year as well as the locals head for the forest to light it on fire.

post-498-0-23421500-1425720557_thumb.png

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the smog of the past week. or so, is coming from myanmarcheesy.gif

what next??smile.png

gosh a pig has just flown by my window,there we gobiggrin.png

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Big sigh!

It is an indisputable fact that wind currents, according to the various wind maps, blow from the South West and from Myanmar presently. Having not examined personally the precise contents of that air I am sadly unable to provide a precise analysis of it!

But never mind, logic and fact combine to confirm that said winds must surely contain "something" and since Myanmar is a prime source of burning (according to NASA), it's perhaps reasonable to presume that that "something" might contain particulate matter, are you keeping up thus far?

All of that is not to suggest that reports from esteemed forum members and others who have reported first hand evidence of local burning are incorrect, indeed they are not The challenge, for those who are willing and able is to determine the percentage split between home grown pollution and imported pollution - were the wind currents in a different direction that challenge might be easier, regrettably for you they are not so perhaps you should ask your pig and see what it has to say on the subject.

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Which ever direction the wind blows from will be the cause of CM pollution in your opinion. Sorry, but you need to look a bit closer to home. Good luck in your search for double glazing, but I think you might have a problem getting the rose tinted finish.

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Which ever direction the wind blows from will be the cause of CM pollution in your opinion. Sorry, but you need to look a bit closer to home. Good luck in your search for double glazing, but I think you might have a problem getting the rose tinted finish.

I expected better from you MES!

One more time, I do not dispute the existence of local burning, the extent of it nor it's impact.

But the larger picture is somewhat more complicated and involves thermals, imported pollution and the inversion layer in addition to home grown burning, listening to many posters here it seems there is only one answer, home grown pollution, I do not agree even a little bit.

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Which ever direction the wind blows from will be the cause of CM pollution in your opinion. Sorry, but you need to look a bit closer to home. Good luck in your search for double glazing, but I think you might have a problem getting the rose tinted finish.

I expected better from you MES!

One more time, I do not dispute the existence of local burning, the extent of it nor it's impact.

But the larger picture is somewhat more complicated and involves thermals, imported pollution and the inversion layer in addition to home grown burning, listening to many posters here it seems there is only one answer, home grown pollution, I do not agree even a little bit.

I am sure some blows in from other areas, but from my experience flying around forest fires in the Pacific Northwest, if you eliminate the fires within 100 km of Chiang Mai, the PM10 levels would never get very high here. The government likes to blame it on other countries as that allows them to ignore all the Thai Nationals that are in the forest setting fires (including tonight) for mushroom season or for agricultural clearing. The air was quite clear this afternoon so I fail to see how much of it is coming from far away, but I will keep an open mind CM.

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MES usually has some commonsensical observations that do indeed make sense. Observations, of course, are at the heart of the scientific analysis.

CM, as you have pointed out, it is true that the problem is a regional problem and that the prevailing wind at this time of the year is basically the SW monsoon. And, as you have pointed out, from there is does indeed get complicated.

We don't have enough good data and knowledge of particle behavior. We don't know how high, how far, and how long PM<10 and, especially PM<2.5 particles fly before settling out. We do know that lighter particles tend to stay aloft longer than heavier particles.

I think you agree that it is reasonable to hypothesize that local conditions have significantly more impact than relatively distant effects. I think that is what MES is generally saying. I agree with him.

An example would be today. For yesterday, FIRMS reported the greatest number of local fires so far this year. (FIRMS, for newcomers, really only reports the more extensive fires, and the satellites don't park above our valley or NW Thailand all day.) This morning it looked like Beijing out there! Really nasty! That, of course, doesn't preclude the impact of Burmese smoke, but think about it! Look at MES' post #157 (and similar ones in the past). I wouldn't be terribly upset about what he reports.

Yes, there is certainly "something" (as you put it) in the SW monsoon, but I agree with MES that one should look closer to home for the major impact.

Now, just to change the topic for a moment, which way are bond yields going to go in 2015?

Cheers!

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