Stove Emission Testing Procedures
Tami Bond, Bond Research Group, Department of Civil & Environmental Engineering
University of Illinois at Urbana-Champaign (UIUC) October 16, 2006
Very sorry to take so long to follow up on this. I can say something about what Aprovecho equipment is and also what we use in the field.
This is only relating to exhaust gas testing-- not fuel testing.
* Measuring what? *
Through a few discussions at ETHOS meetings, we came to the conclusion that we need to test for carbon monoxide (CO) and particulate matter (PM). We also measure CO2 in exhaust gas which enables us to get 'emission factors', pollutant per kg of fuel burned. My ETHOS presentations 2002-2004 are probably on the Stoves page, but also located at...
We could test for many other pollutants (see especially the 2002
presentation) but we hoped to settle on the CO and PM to see if we could do that well.
* Measuring how? Aprovecho *
Around 2003, Aprovecho-- along with a few specifications from me and
others-- started implementing their testing lab. Dale Andreatta set up the flow hood which captures all the exhaust. Some of the exhaust gas is extracted with a little pump (bigger than fish tank, you can get them at Grainger in the U.S.), diluted and measured. CO and CO2 are measured two
ways: in the *undiluted* gas with an Enerac combustion analyzer, and in the *diluted* gas with the CCCD-- I'm embarrassed to say I can't remember what it stands for-- it's a 4" PVC lump that we informally have named the 'bomb' and contains two small CO (electrochemical) and CO2
(infrared) analyzers. Chris Roden, grad student here, designed and built the CCCD for our first trip to Honduras.
PM is measured only in the diluted gas by light scattering (nephelometer). Light scattering is not a perfect measurement, but it is one of the only real time measurements and it is better than extinction.
PM *must* be measured in diluted gas, because some of it will condense gas as cools-- thus if you measure hot gas you are missing some PM.
* Measuring how? in the field *
We also measure emissions from stoves in the field-- because we suspected they would be different than stoves in the lab (they are). If you take the diluted part of Aprovecho's measurements (CO, CO2 and PM) and strap that on a luggage cart, you have Chris Roden's ARACHNE-- Ambulatory Real-time Analyzer for Climate and Health-related Noxious Emissions. (I admit that the acronym was made first and then we found the words!) We also add real-time particle absorption to that. We can tell if the particles emitted are black (soot) or not black. Sometimes they are yellow. The color turns out to be very important for climate.
And finally we collect the particles on filters for total mass and chemical analysis. They are mostly carbon, what you might think of as 'soot' or 'tar'. In order to get a diluted gas sample, we sample high in the plume.
We measured in Honduras in summers of 2004, 2005, 2006. The first paper about ARACHNE, traditional cookstoves only, 2004 measurements, will finally be published in a scientific journal soon (Nov 1). In 2005 we went back to measure improved cookstoves. These stoves had not been installed for very long, so the 2006 trip was to see whether emission performance had degraded, and also to test the contribution of fuel type to emissions. Results are not final yet but will come soon.
There is also a document on my web site... 'Emission testing for real people'... that talks about some testing issues and possible instruments to use. Any comments are welcome.
Sorry if I have missed some of this discussion. I have been traveling a lot lately and so have the Aprovecho folks.
See discussion October 2006