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REPORT: Diesel combustion drives this PM2.5 mess, said PCD latest study


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REPORT: Diesel combustion drives this PM2.5 mess, said PCD latest study

By PIYAPORN WONGRUANG 
THE NATION WEEKEND

 

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THAI AND MUNICIPAL authorities mounted a successful campaign years ago to control air pollution involving PM10 – particulate matter 10 microns in diameter or more. The problem since then – one that’s steadily worsening and more difficult to curb – is PM2.5.

 

It was PM2.5 dust that was choking Bangkok throughout the past week, threatening people’s health and keeping many residents indoors.

 

Making the problem trickier to tackle, according to a Pollution Control Department (PCD) study last year, is the fact that sources of the pollutants are varied and complex.

 

Recommendations were made for easing the seasonal onslaught on Bangkok and its periphery, which included a more effective management system, an idea being pursued this year.

 

Three prime sources of PM2.5 were identified – inefficient combustion in diesel engines, the widespread burning of biomass and chemical processes churning out inorganic secondary particular matter. The last involves mainly diesel fumes and ammonia released by farm fertilisers.

 

The PCD began monitoring PM2.5 in 2011 and watched the particles’ 24-hour “rolling average” exceed the safe level of 50 micrograms per square metre of air for eight straight years. Bangkok’s air was bad for 40 to 50 days every December and every January to March.

 

Department officials settled in to watch again last year from January 1 to March 27, only to witness the 24-hour rolling average of PM2.5 exceed the safety standard by the middle of January.

 

In a 2007 study that focused on the Din Daeng area close to the Victory Monument, a hub for bus traffic, PCD researcher Kim Oanh determined that incomplete combustion in diesel engines was causing 52 per cent of the PM2.5.

Biomass burning accounted for 35 per cent and inorganic secondary PM and other sources the remaining 13 per cent.

 

In 2017 during the dry season Kim looked at the PCD compound in the Aree area, chosen to represent inner Bangkok, and the Asian Institute of Technology, representing outer Bangkok. Again, problems with diesel-engine combustion contributed most of the PM2.5 – 20.8 to 29.2 per cent.

 

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Thai authorities have since 1997 managed to get PM10 dust under control despite a four-fold increase in the number of vehicles on the roads.  The PM10 annual average tends to be within the safe limit, but PM2.5 has increased and in some months exceeds the standard. 

 

Concentrations of PM2.5 were highest in the heart of Bangkok in 2017, according to satellite-based pollution mapping conducted by the PCD. But it was also concentrated in the Northeast because of winds carrying smoke from biomass fires.

 

“The increase in both sizes of particles suggests an increase in sources and complexity, which has created a problem different from the past,” the study report stated. 

 

“The causes need to be addressed so the problem can be properly tackled. Being able to control their levels in the air, even slightly, makes a big difference to people’s health, and that could require that an improved standard be instituted [it is now set at 50 micrograms per square metres].

 

“As for particles exceeding the standard during the dry season, there is a need to introduce more stringent measures in order to get the particles under control,” it said.

 

In 1982, Thailand introduced its first air quality standard, but the focus was on particles wider than 10 microns. 

 

In 2004 a standard was added for particles 10 microns of smaller. Six years later a PM2.5 standard was adopted in light of strong evidence that the tiniest particles could penetrate the bloodstream via the lungs and trigger more critical medical conditions.

 

The World Health Organisation in 2011 declared that there was no safe level when it comes to exposure to PM2.5. The PCD study urged environmental agencies to adopt more stringent standards for air quality and tougher measures to protect health in the long term.

 

The WHO projected that 50,000 Thais would die from air pollution in 2013, at a cost to society of around Bt1.8 trillion.

“Thus, investment in controlling PM2.5 should be worthwhile,” the study said.

 

Prime Minister Prayut Chan-o-cha on Tuesday concurred that diesel combustion was the main source of PM2.5 and instructed agencies to devise countermeasures, such as switching to bio-diesel.

 

Efforts, he warned, would fail without cooperation.

 

REPORT: Let’s nail down SMOG CAUSES

 

Source: http://www.nationmultimedia.com/detail/national/30362542

 

The Nation: 2019-01-19

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The article, poorly, doesn't ever define months/periods the PCD study considered to be the "wet" and "dry" periods for purposes of the study results for BKK air pollution.

 

But according to the included big graphic, biomass burning EXCEEDED diesel emissions during the dry periods at both the AIT and PCD locations surveyed in the study. Even though the text of the article itself doesn't really clearly acknowledge that.

 

I think Jan. to March (the current main smog season) would be considered the dry season for Bangkok...  but the article doesn't tell us that. And once again, it seems like there's an effort here to downplay the burning aspect of BKK air pollution, and focus instead on the vehicle generated stuff.

 

BKK doesn't have the same yearround problem with PM2.5 pollution. It has moderate PM2.5 for much of the year, and then really bad PM2.5 typically from December to March.  So that's the season that the authorities ought to be first looking at reducing the pollution sources for.

 

In a common sense kind of way, it makes sense that burning would be less of a PM2.5 contributor during the "wet" season because the Thais aren't lighting so many outdoors fires when it's pouring down rain. But once it's dry like now, the outdoor fires are lit, and it's those fires that contribute the majority of the PM2.5 during the dry season.

 

 

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Last week I flew from Bangkok to Udon....early evening flight.  Not long after takeoff, I started to see the sugarcane fires......lots and lots of them just outside of Bangkok then tapered off as the plane neared Udon.

 

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Quote

 

A study performed by the Chonbuk National University concluded that a B30 biodiesel blend reduced carbon monoxide emissions by approximately 83% and particulate matter emissions by roughly 33%. NOx emissions, however, were found to increase without the application of an E.G.R. system. The study also concluded that, with E.G.R, a B20 biodiesel blend considerably reduced the emissions of the engine.[64]

Additionally, analysis by the California Air Resources Board found that biodiesel had the lowest carbon emissions of the fuels tested, those being ultra-low-sulfur diesel, gasoline, corn-based ethanol, compressed natural gas, and five types of biodiesel from varying feedstocks. Their conclusions also showed great variance in carbon emissions of biodiesel based on the feedstock used. Of soy, tallow, canola, corn, and used cooking oil, soy showed the highest carbon emissions, while used cooking oil produced the lowest.[65]

 

.......................

 

As of 2017, blended biodiesel fuels (especially B5, B8, and B20) are regularly used in many heavy-duty vehicles, especially transit buses in US cities. Characterization of exhaust emissions showed significant emission reductions compared to regular diesel.[1]

 

 

https://en.wikipedia.org/wiki/Biodiesel#Vehicular_use_and_manufacturer_acceptance

 

So, according to the Nation graphic, diesel emissions account for between 20 and 27% of PM2.5 pollution as measured during the dry season in 2017 at two locations. And, the one cite in the Wiki article above on biodiesel says it has the capacity to reduce PM2.5 emissions by 33%, one third.

 

So, put those two elements together, and it would suggest that converting ALL diesel vehicles in BKK to biodiesel EVERYTHING transportation might produce less than a 10% overall reduction in PM2.5 pollution (one third reduction in a source that accounts for 20-27% of the problem).

 

Up to 10% reduction in PM2.5 wouldn't be bad. But if they STOPPED the agricultural burning, that alone would reduce PM2.5 in BKK by 35-38% during the dry season, according to the Nation graphic in the OP...  So, where would their enforcement/regulatory energies best be spent?

 

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I guess the result, in part, of virtually allowing many to only purchase diesel pick-ups, due to insane pricing of better vehicles.

Of course there's Yaris and Vios etc, but not a whole lot of vehicle for large extended families here.

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It's cheaper to wait for March & let the levels drop to lower figures so they can say it's all okay.

It's time to get strong and change the way things are done... but:

As for enforcing all vehicles to have an annual inspection & removed from the roads if emissions are above tolerated limits, you can forget it.

As for making bio-mass burners fit filtering systems to cut emissions or shut down... forget it.

As for making farmers stop agricultural burning, you can forget it.

As for making construction areas reduce dust pollution you can forget it.

As for asking any Thai or Thai company to do anything is a waste of time... 

Change the laws & enforce them with huge fines or jail time... but you can forget that ever happening.

It's cheaper & easier to make the public buy & wear a mask, not invest hard cash in real solutions !!

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2 hours ago, hotchilli said:

It's cheaper to wait for March & let the levels drop to lower figures so they can say it's all okay.

...

It's cheaper & easier to make the public buy & wear a mask, not invest hard cash in real solutions !!

 

I think your comments above probably get to the heart of the matter.

 

If the smog was at current high/dangerous levels year-round, then EVENTUALLY, the government might be forced to make a typically local half-hearted effort to deal with it and bring the levels down.

 

But since the worst of the smog for BKK typically is a seasonal thing (Dec. to March), they're content to wait it out, do a lot of talking and zero action, and then ignore the whole issue until next December, when the whole process will repeat itself again.

 

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Funny reading all the replies I am amazed that no one has had a go at BMA buses which at their age should have been retired 30years ago. I have a motorbike 6 years old and every time I go to register it they put the gauge up its exhaust to test the emissions, obviously this doesn't happen with the buses (must be the brown envelope syndrome). So therein lies 20-27% of the problem LACK OF ENFORCEMENT. Get your F#####g act together BMA. 

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