Biomass off-gassing: A mini-review and meta-analysis aspiring to inspire future research and innovation in solid biofuels for safety-sensitive and environmentally responsible residential and industrial applications

Biomass offers substantial societal, environmental, and economic advantages. However, the release of harmful gases during its utilization presents critical challenges. To establish secure and environmentally conscious processes for biomass-to-solid fuel conversion, we conducted a concise review and meta-analysis. Our systematic approach identified fifteen incidents of perilous off-gassing associated with biomass between 2001 and 2017, resulting in ten fatalities and five severe injuries. This underscores the urgent need for effective mitigation strategies. Our review emphasizes pivotal gases—carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and volatile organic compounds (VOCs)—as central to off-gassing. Drawing from peer-reviewed articles, technical reports, and reputable sources, we synthesize off-gassing risks and viable control methods in residential and industrial settings. We explore strategies such as ventilation, mechanical drying, and thermochemical pretreatment (e.g., torrefaction, steam explosion), alongside ozonation, supercritical fluid extraction, and antioxidant application. These measures effectively maintain safe indoor gas levels, enhancing occupational safety and mitigating environmental impacts. Our review offers actionable insights for advancing cleaner, safer solid biofuel development, aiding researchers and policymakers in devising solutions to prevent toxic gas accumulation, injuries, and fatalities.