A source strength model for prescribed fires in coniferous logging slash.

Emission reduction has become an essential part of the effort to reduce air pollution from forest slash burning. The State of Washington has set a goal of reducing emissions by 35 percent by 1990, leaving the choice of emission reduction techniques to forest managers. Several thousand harvested areas are burned each year in the Northwest, encompassing a wide variety of physical and meteorological factors that determine the mass and duration of each pollutant source. Each burn is somehow unique; and no emission reduction technique is uniformly effective.

A source strength model has been developed to combine what is known about the factors that control biomass consumption and combustion efficiency in Douglas-fir and hemlock logging slash. Particular matter and carbon monoxide emission rates are predicted from a set of eighteen or more input parameters. Default values or inference techniques are available for most inputs. An interactive model, or used to compile a daily emissions inventory. Iterative model solution has been used to evaluate the effectiveness of emission reduction techniques.