The researchers studied the emission of gases during composting processes. They found that different types of volatile compounds were released during anaerobic/aerobic composting, with alcohols being most common in aerobic composting and terpenes in anaerobic/aerobic composting. The total emission of volatile organic compounds was lower in the combined process compared to aerobic composting alone. The researchers suggest that the combined anaerobic/aerobic composting process is a better option due to its lower emission of harmful gases.