Structural integration of inert porous media as a primary mitigation strategy for firewood stoves: Toward decoupling combustion intensification from emissions

Residential wood combustion in energy-vulnerable contexts creates a critical trade-off between thermal comfort and air quality, while many conventional emission-control technologies require electricity, maintenance, or active control. This study evaluates the structural integration of inert porous media (IPM) within a commercial residential wood stove as a passive primary mitigation strategy. Combustion cycles, conducted following an adapted EPA Method 5G protocol, compared the baseline stove with the IPM-integrated prototype. IPM operation showed a tendency toward a more intensive fuel-conversion regime together with thermal redistribution toward the stove enclosure. Median thermal efficiency was 29.3 % higher, while exhaust-gas temperature decreased by 6.0 % and outer lateral-wall temperature increased by 18.8 %. Despite the higher burning rate, PM 2.5 and CO mass emission factors showed directional decreases of 65.5 % and 30.9 %, respectively; HC remained essentially unchanged, whereas NO x increased. Particle-number emission factors were lower across most of the measured 0.253–35.15 µm size range. Useful-energy normalization strengthened the environmental benefit, with PM 2.5 and CO decreasing by 76.3 % and 33.4 % per unit of useful heat delivered; HC shifted toward a lower burden, whereas the NO x increase was attenuated but remained. Overall, the findings support a pollutant-specific tendency toward decoupling combustion intensification from incomplete-combustion emissions and identify structural IPM integration as a promising passive strategy for improving residential wood-heating performance without auxiliary energy input, particularly where affordability and operational simplicity constrain advanced emission-control technologies.