[Stoves] Particulates and aerosols (was Crispin and Norm on soot)

[Crispin Pemberton-Pigott]

Dear Nikhil

I have to agree with you a bout tiers within standards, though you didn't express it in exactly that manner.

Tiers of performance have no place in a national or international standard. They are referenced in ISO 19867-1 and contained in ISO 19867-3 because the USA wanted them.  To this day no one knows why. Tiers are always negotiated outside the Standards and involve a different set of players. The regulation of a market requires some sort of pass/fail test that either permits a product to be sold, or prevents it. There are serious consequences for trying to sell unapproved products in a regulated market - for example a non-compliant kerosene stove.

I am sure you have heard of the Energy Star rating system. That is a classic web-based performance rating system. It is not part of the regulatory framework and is not part of the standard in, for example, the EU.

It is run by a "group" comprised of the producers, government and consumer organisations. Every now and then they raise or lower the numbers on the tier ratings. That doesn't have any effect on the Standard, which prescribes the minimum performance (on various metric) for "compliance". A product cannot "half-comply". It is either permitted or not. The tiers apply to all the products that are permitted.

As for your repeated dismissal of the importance of emission rate, either per minute or per MJ of useful work accomplished, you are confusing two things which surprised me. You speak of exposure as a metric, while I speak of emissions. As you have repeatedly said, emissions is not directly correlated with exposure. If you want to know someone's exposure you have to measure it. If I want to know the emission rate, I measure it. I am not making any claims about exposure. So why the fuss?

The fact that Berkeley and the WHO both claim they can predict or estimate or guess the exposure from an emission rate (a metric which doesn't interest me) means exactly nothing. They are playing in their modeling sandbox and convincing no one. The model is useless for real world exposure estimates, by their own admission!

That's right - they admit their single box model doesn't correlate with anything real yet they persist in using it. That's not my problem. I am trying to clean up emissions and provide advice on how to do that. So far, so good. We have achieved big health impacts by reducing emissions from coal stoves and dung/wood stoves using metric PM master MJnet. We made no claims or estimates for exposures.

The Dutch International Primary Care Respiratory Group did make claims for exposure based on baseline and replacement stoves. They did not use emission rates or emissions per MJnet, they used personal exposure monitors which is the appropriate method.

If the governments of the world want to have the results obtained in the Kyrgyzstan project, they will have to investigate how the impact was achieved. Was it by changing the fuel? The stove? The ventilation? The room size? The insulation standard? The ceiling height?

One of the things they will probably want to know is the emissions and leakage from the stove for each unit of heating service supplied. Why?   Because in nearly all cases it is one of the relevant factors.

I suggest that one can reduce the leakage and not the total emissions of PM2.5 with big health benefits.  In deep rural areas that is realistic. It reduces exposure through the mechanism or reducing a leakage rate, not an emissions rate. So be it. But while we are "there" why not also improve the com Justin efficiency, the heat transfer efficiency and decrease significantly the amount of time and attention needed to keep the stove running? Such things are easy of accomplishment with dreadful baselines.

Regards

Crispin having fun


From: pienergy2008 at gmail.com
Sent: August 26, 2019 10:28 AM
To: crispinpigott at outlook.com
Reply to: ndesai at alum.mit.edu
Cc: stoves at lists.bioenergylists.org; sujoy.chaudhury at gmail.com; hannegarn at gmail.com
Subject: Particlulates and aerosols (was Crispin and Norm on soot)

Crispin:

I didn't see the title of the original thread, so I started a new name.

What you are saying is that absence of evidence does not mean evidence of absence. To make things worse, one might be looking in the wrong place and for the wrong things.

Why are emission rates relevant even if accurate? (Remember the old joke about lawyers saying things that are accurate but irrelevant.) Concentrations in relevant contexts - mobility and height determining ingestions - are the only valid metrics (and that too assuming equitoxicity and an IER).

There is a fanatic obsession among "scientists" about "measurements", in turn because they help determine "standards".

I submit that if you dispense with such fanaticism, you might see light at the end of the imaginary exhaust pipe. As with the imaginary forests that couldn't be saved, you are now searching for imaginary lives to be saved.

All very beautiful, noble, but gigantic self-delusion for self-indulgence. Tinkering for personal gratification.

I am not being cynical, just pleading for humility. (Yes, only an arrogant ass like me can demand humility. I have a right to, after the fiasco or test standards and ta ta Tiers.)

N
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Nikhil Desai
(US +1) 202 568 5831<tel:+1)2025685831>
Skype: nikhildesai888



On Mon, Aug 26, 2019 at 9:09 AM Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
Dear Norm

Consider this:  If you have sharp corners, is there soot accumulating or not?  If not, there you might have soot in the exhaust. Maybe not. If you have soot accumulating, and you change the shape slightly so it stops accumulating, now you have soot that no longer collects on the corners, and leaves the stove to pollute the air.

Carbonaceous soot forms after combustion in almost all cases. The charged atoms or small molecules are highly reactive and stick together very easily. In the heat the rapidly come into contact and the particles grow quickly. If you measure them just above the fire the total mass will be spread over a large number of particles. If you measure 1 metre above, the same mass can be found, but with a much smaller number of larger particles.  If you measure 1 km downwind, there will be a few very large particles, some of which may have already fallen to the ground.

Look for “giant dentritic particles” and see some micrographs.  They look like a marble collection.  Wet particles composed of condensed tars and volatiles (which your TLUD probably has lots of) stick together wonderfully.  Imagine aerosolized fly paper, a spray of duct tape glue that never reached a surface: sticky stuff floating in the air.

So it if doesn’t accumulate on a surface, it means no cleaning needed, but not that it is absent.  That’s a separate measurement.

I hope your testing goes well.

Regards
Crispin

+++++++


Crispin;

Thank you so much for the explanation. Very interesting. In my latest TLUD design, I have a lot of sharp corners. Later on I plan to test emissions at Aprovecho. Perhaps I could test for this as well.

Thanks again. Most appreciated.

Norm
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