Abstract. Establishment of the sources and mixing state of black
carbon (BC) aerosol is essential for assessing its impact on air quality and
climatic effects. A winter campaign (December 2017–January 2018) was
performed in the North China Plain (NCP) to evaluate the sources, coating
composition, and radiative effects of BC under the background of emission
reduction. Results showed that the sources of liquid fossil fuels (i.e.,
traffic emissions) and solid fuels (i.e., biomass and coal burning)
contributed 69 % and 31 % to the total equivalent BC (eBC) mass,
respectively. These values were arrived at by using a combination of
multi-wavelength optical approach with the source-based aerosol absorption
Ångström exponent values. The air quality model indicated that local
emissions were the dominant contributors to BC at the measurement site.
However, regional emissions from NCP were a critical factor for high BC
pollution. A single-particle aerosol mass spectrometer identified six
classes of elemental carbon (EC)-containing particles. They included EC
coated by organic carbon and sulfate (52 % of total EC-containing
particles); EC coated by Na and K (24 %); EC coated by K, sulfate, and
nitrate (17 %); EC associated with biomass burning (6 %); pure-EC
(1 %); and others (1 %). Different BC sources exhibited distinct impacts on the EC-containing particles. A radiative transfer model showed that the amount of detected eBC can produce an atmospheric direct radiative effect of +18.0 W m−2 and a heating rate of 0.5 K d−1. This study shows that reductions of solid fuel combustion-related BC may be an effective way of mitigating regional warming in the NCP.
Radiative effect of black carbon aerosol on a squall line case in North China
