Comparing Methods to Measure Air Emissions from Commercial Compost Facilities

This technical report evaluates methodologies for measuring air emissions from commercial composting facilities in Washington state. Conducted under the Waste to Fuels Technology Partnership during the 2019–2021 biennium, the study compares approaches for quantifying volatile organic compounds (VOCs) and other emissions associated with diverse composting process configurations.

Given the variability across facilities—including turned windrows, positively aerated piles, negatively aerated systems, and reversing airflow designs—the report assesses strengths and limitations of different sampling strategies. It examines the suitability of surface flux isolation chambers, duct-based measurements, and alternative approaches depending on aeration design and emission pathways. The analysis highlights challenges in accurately capturing emissions from negatively aerated and mechanically forced systems, where airflow dynamics influence measurement accuracy.

Findings are intended to inform development of standardized, scientifically defensible emissions measurement protocols to support regulatory decision-making and improve environmental performance across Washington’s organics management sector.