[Stoves] Between PM 2.5 and PM 10

[Crispin Pemberton-Pigott]

Thanks for that Julien.

 

Something that is not clear from the abstract is whether the 'increase' in
particles is an increase in the number of particles or an increase in the
mass of particles, or an increase in the mass of small particles.

 

" The 3-fold increase in quantities of sub-30 nm particles from improved
cookstoves warrants further consideration by health scientists, with due
consideration to the higher combustion efficiencies of improved cookstoves."

 

What does 'quantities' mean, exactly?

 

"Particles from improved stoves formed clearly defined chain agglomerates
and independent spheres with little evidence of volatile matter ..."

 

This is extremely important to me - the lowering of volatile matter
condensing into particles. The stove burning cleanly means getting rid of
(by burning or not forming them) condensed volatiles. The health
consequences from this fraction is far high than 'dry dust' though I
understand that investigations of the ultra-fines are not nearly
completed/understood.  Ultrafine particles (UF) are well distributed
throughout the atmosphere so we have been living with the impact of them for
a long time. Perhaps we will find BC UF is really bad for us, maybe not.

 

Cigarette smoke is full of condensed volatiles so it is interesting to me to
know if the comparison of PM emissions per se are 'equal to' cigarette smoke
or akin to cigarette smoke, or not nearly as bad as cigarette smoke. It is
quite possible that condensed volatiles from evaporated coal (which
constitutes a lot of the emissions of an igniting coal fire in a poorly
constructed stove - maybe 90%) are a bad as cigarette smoke. The main point
is that the particles are not from combustion, not from almost the complete
lack of it! Roasting fuel is a major source of PM. Cooling a flame against a
cold surface produces PM of a very different nature.

 

It would be unfortunate if we are unable to differentiate between these, and
soon, please.

 

Thanks
Crispin

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