XLance

35 minutes ago, Capacitor said:

 

Interesting interpretation, do you work for the government by chance?

 

It's unlikely that AQI readings consistently above 150 for the last 24 hours are related to fog, which has not once in my lifetime given me a headache, scratchy throat, and itchy eyes.

No wonder there is so much misinformation and scare around if people cannot understand a simple message on a forum.

I replied to your comment about the visibility of Doi Suthep, not about the current AQI level. With an AQI of 150 or 200 (the reason why I used that value in my previous post), you will see Doi Suthep without any issues, even from Hand Dong in a low humidity atmosphere. Since the humidity lately is between 50 and 100%, this reduces visibility by 200 to 300%. If you don't see Doi Suthep right now, it's ~10% because of the haze due to pollution, ~90% because of the fog due to humidity

14 minutes ago, XLance said:

I would find surprising that PM2.5 and PM0.1 would not be mildly proportional to <10^-8m particles, not correlated though, depending on sources. If it's polluted for PM2.5, it's likely to be polluted for PM0.1 and vice-versa.

ah well, it is surprising: https://www.sciencedirect.com/science/article/pii/S0160412019311110

But my remarks about Chiang Mai burning season pollution remain valid though, the particulate size distribution of smoke from grass/shrub burning is relatively well defined and relatively properly monitored by PM2.5

Quote

In short,current PM2.5 meters are ineffective in measuring pollution as they don't count the very smallest particles-nanoparticles,which recent research suggests are a much larger cause of illness & death

Not sure exactly what was said but the definition for PM2.5 measurement is all particles between 2500nm and 30nm. Of course, there are particles below that size, but I would find surprising that PM2.5 and PM0.1 would not be mildly proportional to <10^-8m particles, not correlated though, depending on sources. If it's polluted for PM2.5, it's likely to be polluted for PM0.1 and vice-versa.

As for Chiang Mai, if we stick only to the particles produced by burning, it's around 150nm with a 2sigma between 60nm and 250nm. The amount of particles below 30nm is around 1% so the PM2.5 in Chiang Mai seems to me to be perfectly appropriate to monitor the pollution during the burning season.

23 hours ago, Capacitor said:

3rd straight winter in Chiang Mai and this December has been ridiculously bad. I don't recall a single day in February last year when the mountain vanished behind an impenetrable veil of smoke like today.

 

Obviously it can't be vehicle emissions; is there a fire map or other means to see where the smoke is coming from? Not that it will change anything, but at least to have an idea of what's happening and why.

Somehow, a lot of people seems to have forgotten that normal weather plays a big role in atmospheric visibility. What we had for the last few days is just fog (and a minor component of air pollution).

The humidity level between 4 and 7am these days is basically 100%. Since it doesn't really rain, that humidity remains in the atmosphere and create a fog (not a haze).

Humidity concentration can considerably limit how far you can see.

Based on this diagram, with an AQI of 200 (which is bad in itself), the visibility can be around 20 km (what it would be in March-April) or around 5 km like it is right now.

https://www.chiangmaidoctor.com/burning-season

16 hours ago, Samuel Smith said:

Until the rains stop for a couple of days...

The rain will clean the air, but the very high particulates level in the air are not caused by the absence of rain.

You need a source (bushfires have reduced a lot, so air pollution is now mostly associated with typical city pollution) and the right meteorological conditions (inversion layer, which is rarely possible at this time of the year). Other factors are secondary.

Reduced source and no meteorological process to accumulate particulates cannot lead to very high particulates concentrations, rain or no rain.

On 5/25/2019 at 10:40 AM, at15 said:

And you must remember even 10 μg/m³ is not safe, there is no safe limit of pollution.

Of course not, but what there is a a statistically insignificant effect. It's your right to worry about an insignificant effect, but then there is no reason why you should not worry about everything

On 5/25/2019 at 10:40 AM, at15 said:

And what is even more disturbing is the fact that with air pollution the researchers have found the initial dose is what really damages people. Going much higher only slightly increases the negative health effects, it is not a linear model.

Do you have a peer-reviewed scientific study that support this claim or you (or a journalist) made that up?

Just based on the absorption of air pollutant, I see no reason why it would follow a linear progression (it's a volume/surface contamination) and that's not taking physiological effects into account (which have even less reasons to be linear in this case). My best guess is that health effects probably follow at least a first-order power law (but certainly not something logarithmic like you seem to suggest).

Your claim basically would say (translated in an hypothetical cigarettes per day/DALY) that smoking 10 cigarettes a day will shorten your life by (let's say) 12 months, while smoking 50 cigarettes would be 18 months, smoking 100 cigarettes a day would be 21 months, and 300 cigarettes a day (basically, smoking continuously) would not really change your life expectancy compared to a few packs a day :p...

Provide a peer-reviewed study of those epidemiologists and then it deserves some attention, but I find very improbable that an air pollutant such as those found in PM2.5 in non-industrial areas (i.e. CM) behaves that way. Common sense evidence also show clearly otherwise, respiratory issues in CM increases considerably when PM2.5 is at ~150 μg/m³ and explodes when it's above 300 μg/m³

On 5/25/2019 at 10:40 AM, at15 said:

 So while the Thai authorities may think getting down to 20-25 μg/m³ is okay, really its not much different health wise from sitting at 50 μg/m³. We must be staying under 10 μg/m³ pm2.5 at all times to really have a minimal risk. 

Well, the decision of the Thai authorities regarding health are not entirely objective and evidence-based; it is not that surprising. This year lack of state of emergency for Chiang Mai province is a good example and it wasn't for medical reasons that it wasn't declared.

3 hours ago, OJAS said:

And OA visas.

I just meant that it is less common than work permit (which is a requirement every year), whereas visa extensions, I don't think it is a requirement.

In the O-A case, I would assume that most medical checks are done abroad, which would explain why I rarely see them in Thailand ?

41 minutes ago, RJRS1301 said:

AS well as elephantitus and alcoholism

elephantiasis, yep; and symptomatic alcoholism.... and left wondering why these things in particular ????

That's a new one, they don't require a medical check normally...

You might want to ask a confirmation or the checklist from immigration because I've never heard of that.

The main immigration thing that requires a medical check are work permits. It's mostly just a general check that you are in good health, a check for venereal diseases and in particular, syphillis.

On 5/20/2019 at 7:57 AM, canopy said:

Today marks the official start of the rainy season for this year. The air quality picture of Thailand today shows the north still mired in unhealthy air as we approach June, lagging far behind Bangkok air and other areas of Thailand. Surely the rains will break through the layer of smoke anytime now.

Yes, it should happen soon I think. El Nino has weakened considerably since the beginning of May so that will help as well (and I don't think the Indian Ocean Dipole will have time to develop and delay the monsoon further).

Quote

Just to clarify Medical certificate for renewals ( as across different post's some say required and others say not required.  
Did my 5 year renewal today. Not required 100%.

I renewed my licenses a couple of months ago, it was a requirement... so I guess it might depends on the office person you are talking to. As usual, I take my whole folder of admin paper when dealing with Thai administration...just in case...

On 4/9/2019 at 6:21 PM, bloody tiger said:

Just to clarify Medical certificate for renewals ( as across different post's some say required and others say not required.  
Did my 5 year renewal today. Not required 100%.

 

I renewed my licenses just before Songkran, it was a requirement... so I guess it might depends on the office person you are talking to. As usual, I take my whole folder of admin paper when dealing with Thai administration, just in case.

However, my renewal (car and motorbike) took 30 minutes all together; gave papers at desk 27, did colour check. Wait 5 minutes, get my forms back; pay (don't remember how much, but less than you maybe 300 and 150 ?), then wait another 10 minutes to get my license. jop.

On 5/7/2019 at 8:21 AM, holy cow cm said:

So for a new 1 year renewal motorcycle, is it best to go after your license expires? I road for years being illegal and can't quite remember. The car I did in time last time.. 

My motorcycle license was out of date by a couple of months, it doesn't seem to bother them as long as you don't get stopped by the cops. The car was expired a couple of weeks earlier.  Officially, there is a limit for the expiration date however (6 months or maybe 1 year late) where you have to do extra steps. In real, for Thais at least, I don't think they care.