<div dir="ltr">Paul, Crispin: <br><br>My understanding is that organic aerosols are cooling, soot is warming. The relative proportions depend on the degree of combustion. However, the NCSU authors speak to "<span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">PM that the emissions form over time" and what is more, "</span><font color="#000000" face="Trebuchet MS, Verdana, Arial, sans-serif"><span style="font-size:14px">The effects of atmospheric chemistry are extremely important to understanding the potential air quality benefits."<br></span></font><br>The original full paper <a href="http://pubs.acs.org/doi/pdfplus/10.1021/acs.est.6b05557" target="_blank">In-Use Emissions and Estimated Impacts of Traditional, Natural- andForced-Draft Cookstoves in Rural Malawi</a> Roshan Wathore, Kevin Mortimer, Andrew Grieshop DOI: 10.1021/acs.est.6b05557
Environ. Sci. Technol. 2017, 51, 1929−1938. Supplement <a href="http://pubs.acs.org/doi/suppl/10.1021/acs.est.6b05557/suppl_file/es6b05557_si_001.pdf">here</a>. <span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">This was reported on GACC website. NCSU news </span><font color="#ff0000"><a href="https://news.ncsu.edu/2017/01/cookstove-emissions-2017/">Advanced Biomass Cookstoves Provide Benefits in Field Settings, But Less than Expected from Lab Testing</a> </font>19 January 2017, same day on GACC website <a href="http://cleancookstoves.org/about/news/01-19-2017-advanced-biomass-cookstoves-demonstrate-significant-climate-and-environment-benefits-in-real-life-settings-despite-showing-less-than-expected-benefits-compared-to-lab-testing.html">Advanced biomass cookstoves demonstrate significant climate and environment benefits in real life settings, despite showing less than expected benefits compared to lab testing</a> and <span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">on a UNC blog - </span><span style="color:rgb(0,136,153);font-family:PlayfairDisplayRegular,Georgia,"Times New Roman",Times,serif;text-transform:capitalize"><a href="http://science.unctv.org/content/scienceblog/clean-burning-stoves">These Clean-Burning Stoves May Help Sustainably Feed Nations</a><font size="4"> </font></span>29 March 2017<br><br><font color="#000000" face="Trebuchet MS, Verdana, Arial, sans-serif"><span style="font-size:14px">I can only imagine they are referring to organic aerosols contributing to ground-level ozone. </span></font><font color="#000000" face="Trebuchet MS, Verdana, Arial, sans-serif"><span style="font-size:14px">I very much doubt this is a big issue, unless the density of biomass stoves is very high. Open burning of biomass - crop and tree wastes, forest fires, slash-and-burn agriculture - contribute far more organic aerosols, I suspect. Tami Bond may have done an inventory estimate or may know of some. <br></span></font><br>Still, their argument seems to be that some PM forms over time. <font color="#000000" face="Trebuchet MS, Verdana, Arial, sans-serif"><span style="font-size:14px">I found a very interesting set of pictures by Aditya Sinha, also guided by Andrew Grieshop, at </span></font><a href="https://cleanaircarolina.org/wp-content/uploads/2017/03/Aditya-Sinha.pdf">Measurement of atmospherically relevant secondary organic aerosol from cookstove emissions</a>. This seems to have informed the new paper this week -<font size="2" style="font-family:Helvetica,Arial,sans-serif"><a href="http://pubs.acs.org/doi/abs/10.1021/acs.est.7b01881" style="font-family:Helvetica,Arial,sans-serif">Primary and Photochemically Aged Aerosol Emissions from Biomass Cookstoves: Chemical and Physical Characterization</a> Stephen Reece, Aditya Sinha and Andrew Grieshop, </font><cite style="color:rgb(0,0,0);font-family:Helvetica,Arial,sans-serif;font-size:0.9em">Environ. Sci. Technol.</cite><span style="color:rgb(0,0,0);font-family:Helvetica,Arial,sans-serif;font-size:0.9em">, Article ASAP </span><strong style="color:rgb(0,0,0);font-family:Helvetica,Arial,sans-serif;font-size:0.9em">DOI: </strong><span style="color:rgb(0,0,0);font-family:Helvetica,Arial,sans-serif;font-size:0.9em">10.1021/acs.est.7b01881</span><div><br><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">This is the first time I have read "photochemically aged aerosol emissions". The significant conclusion from this second paper as put in the abstract is "</span><span style="color:rgb(51,51,51);font-family:UniversLight;font-size:18px">More efficient stoves emit particles with greater net direct specific warming than TSFs, with the difference increasing with aging. Our results show that the properties and evolution of cookstove emissions are a strong function of combustion efficiency and atmospheric aging."</span><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px"><br></span><font size="4"><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif"><br>Aha. </span></font>This second paper is based on lab studies (with read oak) unlike the first one. But the two are complementary. I don't have access to ES&T, but I tracked down <a href="https://repository.lib.ncsu.edu/bitstream/handle/1840.20/33669/etd.pdf">Stephen Reece's Masters Thesis </a> with the same title at NCSU, and found this conclusion quite interesting - "Our measurements of primary and aged emissions emphasize that the properties of emissions
from different stoves vary dramatically. For example, the highly oxygenated OA from the FDGS
is distinct from that typically measured for biomass burning emissions and showed relatively
minimal evolution during aging. FDGS emissions had the highest specific mutagenicity in lab
experiments and were associated with no reduction in childhood pneumonia in a field trial. These outcomes could be associated with the stove’s emissions of smaller, highly oxygenated
particles. Further, field performance of cookstoves is often far worse than in lab conditions. Additional measurements of primary and <u>aged emissions</u> should be conducted under real-world
conditions to better understand potential health and climate benefits of these stoves. (Emphasis added.)</div><div>---------<br><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">In short, there is nothing simple about fuels and emissions from cookstoves, and there are no "instantaneous" benefits in disease reduction or climatic effects, local or regional. From a policy perspective, all this scientific research is a research expedition with no definite answers at this stage. <br><br>Corollary: Claims of protecting health or global climate are not yet ripe, and deserve little policy consideration at this stage. When aerosols are included, avoided tCO2e computations get fuzzy. And "health" computations are silly and deceptive anyway. <br><br>Back in 2006, Christoph Roden et al. had written (</span><a href="http://www.stenovne.dk/Roden-2006-Cookstoves.pdf">Emission Factors and Real-TimeOptical Properties of ParticlesEmitted from Traditional Wood Burning Cookstoves</a> Environ. Sci. Technol. 2006, 40, 6750-6757)<span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">, "</span>Although biofuel is an important regional and global
source of particles, it will not be possible to measure emission
quantities and properties for every region. To represent this
source in global or regional emission inventories, <u>the variables
that control emission factors and environmentally relevant
properties, such as EC/PM ratio and light absorption, need
to be identified and quantified by region. These include wood
type, size, and quality, local practices, and stove design;
simply acquiring the appropriate fuel is insufficient. Measurements
of emission quantities and properties should be
linked with these variables and then used to produce regional
emission estimates. </u></div><div><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px"><br></span></div><div><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">Amen. This was only for climate concerns; for health concerns, local and immediate exposures - not just lab emission rates - of the whole suite of gaseous and particulate pollutants matter, over a long term. It will be a long time before scientifically defensible conclusions can be developed for the use of changed stoves upon health and climate. </span></div><div><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px"><br></span></div><div><span style="color:rgb(0,0,0);font-family:"Trebuchet MS",Verdana,Arial,sans-serif;font-size:14px">Nikhil<br><br><br><br></span></div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><font face="georgia, serif">------------------------------------------------------------------------<br>Nikhil Desai</font></div><div><span style="font-family:georgia,serif;font-size:small">(US +1) 202 568 5831</span><font face="georgia, serif"><br><i>Skype: nikhildesai888</i><br></font><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Thu, Aug 10, 2017 at 5:14 AM, Crispin Pemberton-Pigott <span dir="ltr"><<a href="mailto:crispinpigott@outlook.com" target="_blank">crispinpigott@outlook.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Dear Paul</div>
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I believe they are saying that advanced stoves burn more of the carbon which reduces BC and may leave OC. The latter is reflective and thus cooling. </div>
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Biomass emissions are net cooling, improved stoves are moreso. I think that is the message. </div>
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Regards </div><span class="HOEnZb"><font color="#888888">
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Crispin </div></font></span><div><div class="h5">
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<div id="m_7807968013865662140_originalContent" style="background-color:rgb(255,255,255)">Stovers,
<a href="http://onsiteenergymanager.us12.list-manage2.com/track/click?u=affe8bf6b5232eca3c2c1b325&id=37996b6a6d&e=3fd9308259" style="font-size:16px;font-family:Georgia,Times,serif;font-weight:900;color:#0f80c5;text-decoration:none" target="_blank">
<h3 style="margin:0 0 4px 0;padding:0 0 0 0;text-decoration:none;font-size:16px;font-family:Georgia,Times,serif;font-weight:900;color:#0f80c5">
Benefits of advanced wood-burning stoves greater than thought</h3>
</a>
<blockquote type="cite"><span style="font-family:Verdana,Arial,Sans-Serif;font-size:12px;line-height:16px">A recent study from North Carolina State University finds that advanced wood-burning stoves designed for use in the developing world can reduce air
pollution more than anticipated. </span></blockquote>
Article is found at:<br>
<a class="m_7807968013865662140moz-txt-link-freetext" href="http://www.biomassmagazine.com/articles/14586/benefits-of-advanced-wood-burning-stoves-greater-than-thought" target="_blank">http://www.biomassmagazine.<wbr>com/articles/14586/benefits-<wbr>of-advanced-wood-burning-<wbr>stoves-greater-than-thought</a><br>
<br>
But this statement seems contradictory: (maybe an error in the short summary?? I wonder what the full study actually says):<br>
<blockquote type="cite">Advanced stoves are more efficient than traditional ones. So, for example, advanced stoves require less wood to boil a pot of water. However, kilogram of wood for kilogram of wood, advanced stoves produce PM that absorbs more light than
PM from traditional stoves, which produce more reflective PM. Absorbing PM can make a large contribution to atmospheric warming, while reflective PM can offset it.</blockquote>
<br>
Paul<br>
<pre class="m_7807968013865662140moz-signature" cols="72">--
Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a class="m_7807968013865662140moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a>
Skype: paultlud Phone: <a href="tel:(309)%20452-7072" value="+13094527072" target="_blank">+1-309-452-7072</a>
Website: <a class="m_7807968013865662140moz-txt-link-abbreviated" href="http://www.drtlud.com" target="_blank">www.drtlud.com</a></pre>
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