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<div class="moz-cite-prefix">Marc,<br>
<br>
I am delighted to see your involvement with these stove issues.
(To all: Marc and I go back many years with earlier TLUD
work!! He is a great asset for the efforts!!)<br>
<br>
I am also please to be able to (I think) point out an error in
your calculations (helps some, but does not resolve the major
issue, still being discussed). Marc wrote: <br>
<blockquote type="cite">
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><b>Conclusions:
just how small?</b></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">We can do a
back-of-the-envelope analysis to tell the story of the
numbers presented here. If we assume six billion people use
primitive stoves, then one hundred million of them is 1/60
of the total. 1/60 of the four million deaths worldwide is
~67,000. Rocket stoves would save 20% of those lives
according to the exposure-response model: just 13,400.</span><br>
</p>
</blockquote>
<blockquote type="cite"><span
style="line-height:12.8000001907349px">So, you get out
100,000,000 stoves, and you save 13,400 lives. This also
assumes that you achieve the PM emissions reductions in
practice. There are mountains of evidence (academic and
practical) that this is not the case. </span></blockquote>
The error is assuming 6 billion people use primitive stoves.
Actually, about 3 billion would be a useful number. And those
people are living in HOUSEHOLDS, in which perhaps 6 people have
food cooked on one stove. That would be 500 million households
needing seriously improved stoves. That changes your
calculations. If you agree with me, please redo your
calculations and send again.<br>
<br>
Commentary: The highly worthy goal of the GACC to "deliver" 100
million improved stoves by 2020 would accomplish the stove task
for 20% (or 1/5th) of the needed stoves. And we have MUCH work
to do just to reach that 100 million goal. Thank goodness we
have started the efforts. And I suspect that we (the world wide
efforts) could make it by 2020. <br>
<br>
But of those in need, that leaves 80% not reached. And the
initial 20% could probably be the easiest 100 million households
to reach. Simply stated, those who do stove efforts are truly
challenged by the magnitude of the task.<br>
<br>
AND we are faced with the issue that the stoves are NOT performing
well enough to have the desired impact on health. (Favorable
Impacts regarding deforestation / environment habitat for
endangered species, and job creation and carbon balance issues /
CO2 / black carbon, etc, etc. etc. are important and are also
forces that stimulate the stove efforts, BUT we are discussing
mostly the health issues.).<br>
<br>
From the health data (ala Kirk Smith and others) that is shown in
the graph that Marc provided with his comments, there is an
important gap between the CURRENT BEST of biomass-fueled stoves
and the DESIRED low level of emissions (represented by the LPG
stoves, and electric stoves.). Current best (as labeled) are
stoves with fans, better states as FA for Forced Air or Fan
Assisted. Well, perhaps SOME stoves that have fans could be low
in emissions. Simply having a fan does not make a stove perform
well. <br>
<br>
From the health perspective, it seems unlikely that ND (Natural
Draft) stoves are going to have emissions low enough for the
desired health impacts. Even ND stoves that attain Tier 4
ratings (in laboratory tests) still need to be used correctly by
the households. Very challenging!!!!!!!<br>
<br>
Let's see some replies. I am quite happy to have others show that
I am not correct. <br>
<br>
Paul<br>
<br>
<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
On 9/5/2014 12:23 AM, Marc-Antoine Pare wrote:<br>
</div>
<blockquote
cite="mid:CAJLc9BMW2twnxfDcio0Jm3FpJuSaWn+1MUeBQAvfSgyhQVc8kA@mail.gmail.com"
type="cite">
<div dir="ltr">
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px"><font color="#000000">Hi
everyone,</font></span></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:normal">Thanks for
the discussion so far. </span><span
style="line-height:12.8000001907349px">I've looked at the
health numbers for improved cook stoves in some more
detail.</span><span style="line-height:12.8000001907349px"><br>
</span></font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">I
found two major approaches to quantifying the impact on
health by stoves: long term studies and modeling based on
exposure response.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">They
both point to the same overall conclusion: improved
biomass cook stoves will only reduce a small number of the
“4 million deaths” you hear about from indoor air
pollution.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000">Also, it appears that there isn't an
existing biomass technology that will!</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000">Please bear in mind that this is just a few
days of compiling results from research. All of these
conclusions are tentative. I welcome any and all criticism.
The reading has been quite educational so far.</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">One
note at the start: the studies here consider the negative
effects on respiratory health by particulate matter (PM).
The studies I read note that this is by far the largest
contributor to the burden of disease from indoor air
pollution.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><b><font
color="#000000">Long-term studies</font></b></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><i style="line-height:normal">Effect of
reduction in household air pollution on childhood
pneumonia in Guatemala (RESPIRE): a randomised controlled
trial (2011)</i><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000">523 households involved. About half get an
improved plancha stove, which reduces exposure about 50%.
Eighteen months later, there was a 22% reduction in cases of
pneumonia.</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">Note
that in this population, there were 9 deaths attributed to
pneumonia. This is important later.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">Also
important to note is that aid workers regularly coached
these households in usage and maintenance.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><i><font
color="#000000">A Recipe for Success?<b> </b>Randomized
Free Distribution of Improved Cooking Stoves in Senegal</font></i></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">98</span><span
style="line-height:12.8000001907349px"> households get a
stove for one year. Respiratory disease symptoms for
cooking women drop by 8%.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><i
style="line-height:12.8000001907349px"><font color="#000000"><br>
</font></i></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><i style="line-height:12.8000001907349px">UP
IN SMOKE: THE INFLUENCE OF HOUSEHOLD BEHAVIOR ON THE
LONG-RUN IMPACT OF IMPROVED COOKING STOVES</i><br>
</font></p>
<p style="margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000" face="arial, helvetica, sans-serif"><span
style="line-height:12.8000001907349px">5 years, 15,000
Indian households </span><span
style="line-height:12.8000001907349px">(!) </span><span
style="line-height:12.8000001907349px">“</span><font
style="line-height:12.8000001907349px"><font>We find no
evidence of improvements in lung functioning.”</font></font><br>
</font></p>
<p style="margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><font face="arial, helvetica, sans-serif"><font
style="line-height:12.8000001907349px"><font>T</font></font><font
style="line-height:12.8000001907349px"><font>he critique
of this study is that they used </font></font><font
style="line-height:12.8000001907349px"><font>mud stoves
with chimneys that </font></font><font
style="line-height:12.8000001907349px"><font>weren't </font></font><font
style="line-height:12.8000001907349px"><font>all that </font></font><font
style="line-height:12.8000001907349px"><font>clean-</font></font><font
style="line-height:12.8000001907349px"><font>burning</font></font><font
style="line-height:12.8000001907349px"><font>.</font></font></font><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><b style="line-height:12.8000001907349px">What
the long-term studies tell us</b><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">I
was surprised that the number of stoves required to impact
health was so high. In the Guatemala study, you need 250
stoves to prevent about 10 cases of pneumonia.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">Another
interesting thing to note is that I didn't find any
studies that monitor big enough populations for long
enough to quantify how many </span><i
style="line-height:12.8000001907349px">deaths </i><span
style="line-height:12.8000001907349px">are prevented by
improved stoves. Again, in the Guatemala study, the stoves
saved somewhere between 1-5 lives. This number is so small
that it's really tough to extrapolate it </span><span
style="line-height:12.8000001907349px">at all.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">Clearly
something funny is going on here. Why exactly are the
numbers so small? Did people use the stoves incorrectly?
Would better stoves have helped? And why did nothing
happen in India?</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">One
approach to answering these questions is to dig in to the
mechanism for saving lives with stoves. We do this with
the exposure response to pollutants.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><b><font
color="#000000">Modeling based on exposure-response</font></b></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">Health
impact from exposure to PM is well studied. Exposure
amount predicts quite accurately future health problems.
This is great because it let's us start answering the
question: just how clean do stoves need to get to
meaningfully impact health?</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">We
can really get into a lot of detail here. It's a
dissertation's worth of calculation to come up with these
numbers (see: THE DEVELOPMENT OF NUMERICAL TOOLS FOR
CHARACTERIZING AND QUANTIFYING BIOMASS COOKSTOVE IMPACT)</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000"><span style="line-height:12.8000001907349px">Kirk
Smith presented a summary of what exposure-response can
tell us about stoves at the Clean Cooking Conference just
this May.</span><br>
</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px"><font color="#000000">Here's
the graph:</font></span></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><font
color="#000000">[attached]</font></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">The key note is that
a rocket stoves “leaves ~80% of the burden [of disease]
untouched”. That means that even if we give everyone a
rocket stove, only 20% of the 4,000,000 deaths from IAP will
be affected.</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">Here's the reasoning.
The red line in the graph is called the “exposure-response
relationship”. It's a log-linear relationship. That means
that most of the damage from PM exposure occurs from zero
exposure to a very small amount of exposure.</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">It turns out that
improved cook stoves – even the very fancy fan stove
developed by Phillips – don't reduce emissions below that
initial amount of very dangerous exposure.</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">Kirk Smith provided
this summary in London: “Current Health Evidence shows now
that even major reductions (<90%) in emissions still lead
to small health improvements”</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><b>Conclusions:
just how small?</b></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">We can do a
back-of-the-envelope analysis to tell the story of the
numbers presented here. If we assume six billion people use
primitive stoves, then one hundred million of them is 1/60
of the total. 1/60 of the four million deaths worldwide is
~67,000. Rocket stoves would save 20% of those lives
according to the exposure-response model: just 13,400.</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">So, you get out
100,000,000 stoves, and you save 13,400 lives. This also
assumes that you achieve the PM emissions reductions in
practice. There are mountains of evidence (academic and
practical) that this is not the case. </span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">I am trying to find
what I am missing here. I really expected the link to be
much more clear and significant. Is there some other reason
that stoves are promoted besides health benefit? Is there
some overarching strategic goal that I'm missing?</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">Really, I'm looking
for some number to tell the story. All the numbers I have
found point to the fact that stoves, even the very best ones
we have, won't move the needle on deaths from IAP.</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">I would be very happy
to be wrong about this. I know that development issues can
be confoundingly complex, and I would welcome another
perspective on this.</span><br>
</p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px"><span
style="line-height:12.8000001907349px">One silver lining to
all of this is that I think it would be great for technology
developers to hear that current technologies are totally
inadequate. There's nothing like an impossible challenge to
galvanize the inventor :)</span></p>
<p
style="font-family:arial,sans-serif;font-size:13px;margin-bottom:0in;line-height:12.8000001907349px">-
Marc Paré</p>
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