The impact of cookstove operation on PM2.5 and CO emissions: A comparison of laboratory and field measurements

Inefficient biomass combustion in traditional cookstoves generates high levels of household air pollution (HAP) that is associated with numerous adverse environmental and human health conditions. Many cookstoves have been evaluated using laboratory tests, but past studies revealed discrepancies between laboratory and field measurements. Fuel re-loading, a common operation in actual use but not required in the laboratory test, might be a contributing factor to this laboratory-field gap. In this study, we evaluated the pollutant emissions performance of a semi-gasifier cooking stove using both laboratory and field measurements. Emission factors and real-time properties of CO and PM₂.₅ were separately measured during the following 4 phases of a typical cooking event: lighting, stable combustion, fuel re-loading and post fuel re-loading. We quantified the CO and PM₂.₅ contributions to total cooking event emissions in each phase. We found over 70% lower PM₂.₅ emissions and 60% lower CO emissions during 3 no re-loading laboratory tests compared with all 16 field tests. Lighting generated 83.8% ± 15.6% of the total PM₂.₅ and 39.1% ± 7.8% of the total CO in laboratory tests without fuel re-loading, and 57.8% ± 33.5% and 37.9% ± 21.2% of the total PM₂.₅ and CO in field tests, respectively. On average, fuel re-loading led to 29.1% ± 30.8% of PM₂.₅ emissions and 24.9% ± 22.6% of CO emissions in 16 field tests, which also contributed to significant discrepancies between laboratory and field-based emissions. According to the ISO IWA tiered stove ratings for emissions, fuel re-loading led to at least one tier lower ranking in both laboratory and field cookstove tests. Fuel re-loading could be an important factor causing laboratory-field discrepancy of emissions, thus it could be considered in future cookstove selection and intervention projects.