Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

As follow-up efforts for measurements on emission factors (EFs) of fine particulate matter (PM2.5) and its carbonaceous fractions for China's household coal stoves, a large-sized dilution sampling system was designed to test a total of 20 coal/stove combinations, which involve five coals with wide-ranged geological maturities and three stoves. Coal smoke was simultaneously collected onto quartz filter for organic carbon (OC) and elemental carbon (EC) analyses by thermal-optical reflectance (TOR) protocol and monitored online for optical black carbon (BC) by Aethalometer. The mean EFs based on burned fuel weight of PM2.5, OC, EC, and BC are 4.25 ± 2.45, 1.11 ± 0.72, 1.43 ± 1.17, and 0.60 ± 0.42 g/kg for bituminous coal, and 1.44 ± 0.67, 0.05 ± 0.02, 0.04 ± 0.02, and 0.01 ± 0.01 g/kg for anthracite, respectively. Significant differences are observed among the EFs for various coal/stove combinations, which are attributable to the differences of coal maturity, burning style and stove efficiency. Although the EFs of BC and EC are closely correlated (r = 0.97), the average BC/EC ratio is only 0.39, indicating a significant gap between the two methods; and the optical attenuation cross-section (σ) for fresh coal smoke can be deduced as 6.47 m2/g, much lower than the manufacturer's preset value of 16.6 m2/g for Aethalometer.