Dear Andrew "Generally particulates are formed in the secondary combustion area. From a long term health point of view particulates remain the bigger problem over straight thermal conversion efficiency."
This is certainly an area of active interest. What I seen so far shows very little in the way of particles when the combustion is limited to a region of low excess air and high temperature. It is a very reproducible effect. We can go from nearly zero ug to say 2 mg/m^3 just by changing the amount of secondary air. This supports your view about the secondary combustion zone. Tami Bond also talks about particle growth in this zone, as does Harold Annegarn. Actually Harold said something interesting the other day which is that the very small particles emitting from a chimney grow quite a lot in size by the time they have travelled a kilometer or so, bumping into each other and growing. In other words, measuring particles and condensed particles in a stack does not necessarily give a predictable characterisation of airborne emissions. Happy Hols! Crispin _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address Stoves mailing list to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/ [email protected] http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
