[Stoves] report with dissapointing results from cleaner cookstoves-new take

Wed Dec 14 13:15:28 CST 2016

Dear Stovers,

I have visited this study area during the study. In the so called clean intervention villages, the air was still full of smoke.

Smoke from burning trash.
Smoke from neighbors.
Smoke from stove stacking.
Smoke from inappropriate use.

In general people did love to use the stove for cooking.

I have pictures to proof this.

Problem is that the dose-effect relation is non-linear. A 50% decrease will not show up in any way. Even a 75% decrease will be hard to show up. It is 95% or better reduction that is needed. Even with electrical cooking that will not be reached without other interventions.

But also do bear in mind that the circumstances in which this study was carried out are really incredibly difficult. It is easy to judge, but way more difficult to correct.
I also assume there was pressure to publish. Still my conclusions would have been different. Less damaging for the stove work of which I believe will be one piece of the puzzle to improve situations in Malawi.

Malnutrition was also rampant in the area.

Kind regards,

Paul.

-----Original Message-----
From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Andreatta, Dale A.
Sent: dinsdag 13 december 2016 23:26
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] report with dissapointing results from cleaner cookstoves-new take

The drum I've been banging on lately is the question of whether the cook loves the stove.  It's been a few days since I looked at the original article, but I believe the picture showed a batch load stove with a very small fuel chamber, with a pile of large wood in the background.  If the user has to break the wood into small pieces, and/or remove the pot to add the fuel, they probably won't use the stove.  I've not looked at the original paper in the Lancet, but it would be interesting to know if they tracked how much the stove was used.  I suspect it wasn't used very often.

As others have pointed out, there appears to be a lot of background smoke from various sources.  I recall data from the article that said particulate levels were still pretty high even when using LPG, which produces virtually no particles.  It might be possible they were never going to get a measurable health effect, no matter how clean the stove.

Finally, I'll suggest there could be something funny with the statistics.  I'm not an expert, but I think the basics of statistical analysis goes like this:

Step 1, set up a hypothesis to measure:  The stove makes a difference.
Step 2, this determines the null hypothesis:  The stove doesn't make a difference.
Step 3, pick a confidence level:  Let's say 90%.
Step 4, do the experiment and determine how confident you are that the hypothesis is correct.
Step 5, if greater than 90% confident, report that the stove makes a difference.
Step 6, if 89% or less confident the stove makes a difference, report that the stove makes no difference.

I question the last part.  I think this is why we are constantly see conflicting information about "Eggs are bad for you", then "No, eggs aren't bad for you".

In the clean water community they struggle with similar issues.  It's my understanding that there have been very few rigorous studies that have showed that anything makes a difference.

Dale

-----Original Message-----
From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Andrew Heggie
Sent: Wednesday, December 07, 2016 11:46 AM
To: Discussion of biomass cooking stoves
Subject: [Stoves] report with dissapointing results from cleaner cookstoves

http://www.bbc.co.uk/news/magazine-38160671

It's a surprising result and I would like to know why the cleaner stoves used did not return a lower incidence of respiratory infections.

Is is because there are other vectors of the  illnesses linked to poverty?

The two  good results were that the cleaner stoves appear to be safer and more economical to use.

AJH

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