Emission characteristics of particulate matter and VOCs in cow dung combustion

초록

1. Introduction The purpose of this study was to determine the size distributions of PM and the specific volatile organic compounds (VOCs) emitted from cow dung combustion. This study characterized the emission of fine particles and VOCs from cow dung combustion in controlled experiments. 2. Methods This study used a dual cone calorimeter (Fire Testing Technology, East Grinstead, West Sussex, UK) to observe the generation of PM and VOCs from cow dung samples at various combustion temperatures. According to ISO 5660-1, the combustion temperatures were estimated to be 459℃, 560℃, and 735℃, when the radiation strengths were 15, 25, and 50 kW/m2, respectively. Concentrations of pollutants were determined using a dust spectrometer for PM and GC/MSD for VOCs. Flow rate, total sampling time, and the weight of burnt material were recorded automatically by the cone calorimeter. The combustion experiments were repeated three times for each heat flux. SPSS ver. 13.0 (SPSS Inc., Chicago, IL, USA) was used to statistically analyze the data. 3. Results This study characterized PM and VOC emissions from cow dung combustion in a controlled experiment. Dung from grass-fed cows was dried and combusted using a dual cone calorimeter. Heat fluxes of 10, 25, and 50 kW/m2 were applied. The concentrations of PM and VOCs were determined using a dust spectrometer and gas chromatography/ mass spectrometry, respectively. PM and VOC emission factors were much higher for the lower heat flux, implying a fire ignition stage. When the heat flux was 50 kW/m2, the CO2 emission factor was highest and the PM and VOC emission factors were lowest. Particle concentrations were highest in the 0.23-0.3 nm size range at heat fluxes of 25 kW/m2 and 50 kW/m2. Various toxic VOCs including acetone, methyl ethyl ketone, benzene, and toluene were detected at high concentrations. Although PM and VOC emission factors at 50 kW/m2 were lower, they were high enough to cause extremely high indoor air pollution. The characteristics of PM and VOC emissions from cow dung combustion indicated potential health effects of indoor air pollution in developing countries.