Emission Profiles and Toxicity Assessment of Sawdust–Waste Paper Briquettes for Clean Household Energy

Sawdust-Waste Paper Briquette Emissions and Toxicity

Abstract

The study examined the emission characteristics and toxicity index of biomass briquettes produced from sawdust and waste paper, an area that remains relatively underexplored in briquette research. Five different sawdust–paper blends were prepared and analysed for carbon monoxide (CO), carbon dioxide (CO₂), particulate matter (PM₂.₅), and an overall toxicity index. These properties were examined under simulated household cooking conditions using standardized experimental procedures. The results indicated that increasing the proportion of waste paper in the briquettes consistently reduced CO, CO₂, and PM₂.₅ emissions. Accordingly, the 100% waste paper formulation exhibited the cleanest combustion profile. In contrast, briquettes with higher sawdust content emitted significantly greater levels of CO, CO₂, and PM₂.₅. Importantly, all briquette samples emitted CO and CO₂ concentrations below internationally accepted indoor safety thresholds. Only the 100% waste paper briquettes and the 30/70 sawdust-paper blends met the U.S. EPA 24-hour PM₂.₅ limit of 35 µg/m³. These findings are consistent with previous studies on biomass combustion and provide empirical support for substituting conventional wood-residue biomass with paper-based waste. The study provides important insights into optimiszing cleanburning biomass fuels in alignment with the Sustainable Development Goals (SDGs), particularly those related to clean energy, public health, responsible production, and climate action. Overall, the findings demonstrate that paper-dominant briquettes offer a practical pathway for reducing indoor air pollution while advancing circular waste management.