<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-CA" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Dear Norbert<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Just for comparison, JICA contractors measured a sustained level of 30,000,000 micrograms per m<sup>3</sup> in Ulaanbaatar apartment building chimneys. That was in about 2010. I think a lot of it
was fly ash. Must have been – surely?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Wow<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Crispin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<div>
<div>
<p class="MsoNormal">Ron and Andrew:<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">I checked Andrew's alibaba link, and the specs state a range of 0 - 1000 micrograms PM/m3, ie., 1 mg/m3, which seems in the range of ambient air measurements. By comparison, a 1 g/kg PM flue gas measurement
(fairly clean) would convert to around 85 mg/m3.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">It looks similar to personal monitors that use the Sharp GP2Y1010Au optical dust sensor, which is described here at Adafruit:<br>
<a href="https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.sparkfun.com%2Fproducts%2F9689&data=02%7C01%7C%7Cf6c3477ad6be4b709bd808d6181518a4%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636722876210411138&sdata=VEbwuN8TvkrZiwu02xuPq1Ruai0NPd4dC876DFx4vf8%3D&reserved=0">https://www.sparkfun.com/products/9689</a><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Data sheet is available here:<br>
<a href="https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.sparkfun.com%2Fdatasheets%2FSensors%2Fgp2y1010au_e.pdf&data=02%7C01%7C%7Cf6c3477ad6be4b709bd808d6181518a4%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636722876210411138&sdata=lQjPouUHfbalaMJ4KQ%2BoahL9knrhoWs8B0INKMvKGSo%3D&reserved=0">www.sparkfun.com/datasheets/Sensors/gp2y1010au_e.pdf</a><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Norbert<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
</div>
</div>
</div>
</body>
</html>