[Stoves] PM emissions from engines

Wed Jun 7 09:49:28 CDT 2017

Dear Nikhil

I think I should expand a little so there is less confusion, or as little as possible for the moment.

The KG (Kyrgyzstan abbreviation) involved both some before and after measurements (48 hrs) with 51 homes participating and a control group (20 homes) which did not receive a new stove. In TJ (Tajikistan) we had 40 homes with new stoves. In TJ we measured temperatures and fuel consumption including time of loading and frequency. No IAQ.

The outdoor air is extremely clean in KG. Any avoided leakage that was turned into outdoor emissions has no meaningful effect on air coming into homes. Clearly the circumstances with Malawi were different in that respect, but that does not mean the studies were functionally different. By that I mean both monitored a cohort with and without improved stoves, and both tracked their health with the ‘difference’ being the exchange of cooking and or heating products.

I think changing the stoves in KG produced health and financial impacts that were predictable. The things we have yet to parse is which health changes were produced by the room being warmer and which by air being cleaner. The inclination of smoke people is to sae the cleaner air, but I am far from convinced.  I want to see the whole report and temperature data. We should be able to construct a chart showing the progressively better effects of heating properly to a high and higher temperature up to say, 25 C which is apparently their preferred temperature. A warmer kitchen brings higher social status. A colder kitchen brings sniffles, coughs, bronchitis and makes colds and flu worse.

I find it odd that smoke is held to be a disease agent for URT and LRT. As you say, a stove is not a pill. What are the co-factors for URT? That is way above my pay grade.

I have written to the participants in the Warsaw BC Summit pointing out that to reduce BC is not only a matter of calculating a reduction in PM per delivered MJ (which is a good metric) but also of adding BC emitted according to the extra Joules that were delivered to the home once the stove was up to the task of doing so with less fuel. Remember I reported that the stoves are delivering about 40% more heat with 40% less fuel. The metric PM mass/MJNET is OK, if you remember to multiple the MJ delivered by the increase in heat ‘desired’ and provided. If you deliver 40% more heat and only reduce the BC 20% per MJNET things are worse on the BC score.

Regards
Crispin

Crispin:
I take a different view on your comparison of Kyrgyzstan v. Malawi studies. From what I can tell of the Kyrgyz study - I haven't yet read full report on methodology and results - it is qualitatively different from the Malawi study in various respects, the main one being that the former is for the same households before and after an intervention whereas the latter had a different fuel/stove combination altogether.

Also, I maintain heating and cooking are different functionalities, so to call these two studies "functionally the same" is mistaken. That "changing the stove improves health in specific ways" is not - repeat, NOT - obvious and categorical for all cookstoves.

Besides, the "neighborhood" effect may not be insignificant. In Kyrgyzstan, the intervention stoves may have emissions too low to have made any effect outdoors, which was probably not the case in Malawi.

In short, I do not give much weight to household emissions and exposure testing. Your Kyrgyz project needs to be implemented at scale to show an overall "modernization" impact that I expect of it - better comfort, insulated homes, better windows, what not.

Too much money is being made off talking about poor people's lungs. People are more than oxidation machines.

And cookstoves are also more than oxidation machines.

Nikhil

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Nikhil Desai
(India +91) 909 995 2080
Skype: nikhildesai888

On Tue, Jun 6, 2017 at 5:15 PM, Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
Andrew sez:

"Okay, so far part of a good answer: so are you actually saying that indoor air pollution is not a quantifiable cause of bad health, yet we know respiring particulates is?‎"

Exactly. We can claim that indoor air pollution has a negative, if unquantified, impact on health. Quantifying that impact is expensive.

The Malawi study and the Kyrgyzstan study are functionally the same: observe the health of HH members one by one in homes with and without the stoves claimed to be improved. ‎The Kyrgyzstan investigation also measured the exposure to which individuals were subjected which is about as good as it gets.

The results were quite different. In Malawi the background PM overwhelmed any impact / reduction in exposure caused by the stove, at least on a macro-impact level. Child respiratory infections did not change in a statistically significant way. In Kyrgyzstan the needle moved to zero which is very significant.

Was the disease in the unimproved stove homes caused by smoke? Low room temperature throughout the day? Cold at night? Gases not considered measurable PM?

It is clear the effect was produced by the stove system. In house after house the effect was seen, not just taken together and shown 'statistically'.

So we can take that as 'obvious and categorical evidence' that changing the stove improves health in specific ways. To claim that PM causes bronchitis is a stretch, however. PM is not a disease agent any more than a stove is a pill. Removing all PM from a chronically under-heated home ‎might have no effect at all.

For all the noise usually made about how women do all the cooking and young children hang around them ‎getting exposed, the Kyrgyzstan project showed that men are more exposed to PM2.5 than everyone else. Put that in your corn-cobbie and smoke it!

In the Naryn region, Dr Sooronbaev says 100% of adults over 40 have COPD‎. That is probably caused directly by exposure to stove smoke indoors.

Crispin
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