Dioxins from Wood Burning

[lshadoff@brazosport.cc.tx.us (Lewis A. Shadoff)]

The Expert Advisory Committe on Dioxins for the Canadian government
evaluated the environmental impact of wood burning.(1)  While done some
time ago, the data should still be valid.  I did the mathematical modelling
referred to below.

<QUOTE>
4.1.3.    WOOD BURNING

The  potential  production  of chlorinated  dioxins from the combustion of
uncontaminated wood raises the possibility of background levels of dioxins
from natural  sources  such as  forest fires.   Dioxin production has been
measured from wood-burning stoves although investigators disagree on the
interpretation of the results.  At the present time, however, the significance
of such sources cannot be assessed.  The reasons for dioxin production from
wood burning are unknown but some work suggests that the trace quantities of
chloride in natural wood are sufficient to enable the formation of chlorinated
dioxins.  Using mathematical  models  and  the  available  data  on  dioxin
production from such sources, maximum air concentrations of about 5 X 10-7 ng
dioxin/m3 and maximum surface concentrations of about 0.2 ng/m2 are predicted
for a situation of 50 wood-burning homes within a 1 km radius of each other.
These estimates are substantially less than those associated with municipal or
industrial  incinerators.   Such sources of dioxin entry and distribution into
the environment could be significant in locations where wood burning is
prevalent.
<END QUOTE>

(1) "Report of the Joint Health and Welfare Canada/Environment Canada
Expert Advisory Committee on Dioxins", G. Bellward, J-F Boivin, F.C.
Fraser, F.W. Karasek, R. Roberts, L. Shadoff, G.R.B. Webster, and R. F.
Willes, November 1983 (Published by Health and Welfare Canada and
Environment Canada)



Lewis A. Shadoff BS, PhD, Lake Jackson, Texas