Hourly emission estimation of black carbon and brown carbon absorption from domestic coal burning in China.

Residential coal combustion (RCC) emission demonstrates obvious daily variation, while no real-time estimation of air pollutants from RCC has been reported, as the limitation of hourly activity data and emission factors. With a dilution sampling system, a high-precision electronic balance, and an Aethalometer Model AE33, a real-time monitoring platform for RCC emission was established. Hourly emission factors (EFs) of BC and absorption emission factors (AEFs) of BrC from eleven kinds of chunk coals and nine kinds of honeycomb coals burning in China were obtained. The monthly and hourly coal consumption amounts were calculated with the activity data from literature reviews and a field survey. The first hourly BC and absorption cross section of BrC emission inventories from RCC were established in China. The historical emission trends (2003-2017) indicated that the policy has rapidly controlled the emission of BC and ACS from RCC in urban area (26.7% and 31.8% decreased, respectively in 2013). While in rural areas, their emission continually increased by 1.2% ~ 5.3% until more strict law enacted in 2017. Emissions of BC and ACS in winter seasons were 60.1 Gg and 1064.1 Gm, which accounted for 54.3% and 55.1% of the total BC and ACS emissions correspondingly. The peak values of hourly emission of BC and ACS (in 370 nm) normally appeared at 19:00-23:00, accounting for 43.0% and 41.5% of their total daily emission. The low emission periods were at cooking times including 7:00, 12:00, and 17:00 of a day and the whole emission of BC and ACS for the three periods accounted for 1.8% and 2.3% of their daily emission. This high-resolution BC and ACS emission inventories can be useful for future modeling works on the formation and evolution of a haze event, the smoke aging and transportation, as well as corresponding climate and human health effects.