Emission Characteristics of Primary Brown Carbon Absorption From Biomass and Coal Burning: Development of an Optical Emission Inventory for China

Abstract

Brown carbon (BrC) affects the Earth's radiative balance due to its strong light absorption at short wavelengths. A custom‐made combustion chamber was used to simulate biomass and coal burning and to investigate the emission characteristics of BrC absorption. Absorption Ångström exponents (AAEs) at the wavelength pair of 370 and 880 nm ranged from 1.19 to 3.25, suggesting the possible existence of BrC in biomass‐ and coal‐burning emissions. Based on the assumption that AAEBC = 1.0, BrC from biomass burning contributed to 41–85% of the total particles light absorption at 370 nm, which is much higher than that from coal burning (15–18%). The estimated absorption emission factors of BrC at 370 nm for biomass and coal burning were 15–47 and 2–13 m2/kg, respectively. A 10 × 10 km gridded BrC optical emission inventory for biomass and coal burning in China for 2015 was developed based on the measured absorption emission factors of BrC values and high‐resolution activity data. The total annual BrC absorption cross section emissions from biomass and residential coal burning were 4,194 Gm2 (relative uncertainty at the 95% confidence level of −33.2, 41.2%) and 615 Gm2 (−39.3, 40.1%), respectively. These results should be useful for improving estimates of the radiative effects of BrC in China.

Emission of trace gases and aerosols from biomass burning – an updated assessment

“…To convert between organic carbon and organic matter (OM), a default OM/OC mass ratio of 1.6 is used in the absence of specific information. This value is based on the data from fresh biomass smoke aerosol in the literature (Turpin and Lim, 2001;Aiken et al, 2008;Yokelson et al, 2009;Takahama et al, 2011;Kostenidou et al, 2013;Brito et al, 2014;Collier et al, 2016;Fang et al, 2017;Tkacik et al, 2017;Ahern et al, 2019;Lim et al, 2019). Where only O/C ratios were given, they were converted to OM/OC ratios using the relationship given in Aiken et al (2008).…”

Emission of trace gases and aerosols from biomass burning – An updated assessment

“…In 20 view of the importance of the number concentrations of aerosol particles, especially cloud condensation nuclei, for climate change, it is unfortunate that there have only been a few additional measurements of their emission factors in the last two decades. Another climate-relevant component, for which we have no emission data at this time, is brown carbon (Andreae and Gelencsér, 2006), which has been shown to account for about half of the aerosol light absorption by biomass smoke at 401 nm (Selimovic et al, 2019) and 25-45 % at 550 nm (Tian et al, 2019). 25…”

High Contribution of Secondary Brown Carbon to Aerosol Light Absorption in the Southeastern Margin of Tibetan Plateau

“…The authors are grateful to the staff of the Lijiang Astronomical Station, Chinese Academy of Sciences, for their great assistance with field sampling. A more detailed discussion of the methodology can be found in the supporting information (Bohren & Huffman, ; Chow et al, ; Kang et al, ; Kondo et al, ; Lack & Langridge, ; Mao et al, ; Moosmüller et al, ; Shamjad et al, ; Tian et al, , ; Wang, Cao, Han, Tian, Zhang, et al, ; Wang, Cao, Han, Tian, Zhu, et al, ; Zhang et al, ). The used data are available from Fire Information for Resource Management System (https://firms.modaps.eosdis.nasa.gov) and cited sources.…”