Abstract. Biomass burning can significantly impact the chemical and
optical properties of carbonaceous aerosols. Here, the biomass burning
impacts were studied during wintertime in a megacity of Nanjing, eastern China.
The high abundance of biomass burning tracers such as levoglucosan (lev),
mannosan (man), galactosan (gal) and non-sea-salt potassium (nss-K+)
was found during the studied period with the concentration ranges of
22.4–1476 ng m−3, 2.1–56.2 ng m−3, 1.4–32.2 ng m−3 and
0.2–3.8 µg m−3, respectively. The significant contribution of
biomass burning to water-soluble organic carbon (WSOC; 22.3±9.9 %) and organic carbon (OC; 20.9±9.3 %) was observed in this
study. Backward air mass origin analysis, potential emission sensitivity of
elemental carbon (EC) and MODIS fire spot information indicated that the
elevations of the carbonaceous aerosols were due to the transported
biomass-burning aerosols from southeastern China. The characteristic mass
ratio maps of lev∕man and lev∕nss-K+ suggested that the biomass fuels
were mainly crop residuals. Furthermore, the strong correlation (p < 0.01) between biomass burning tracers (such as lev) and light absorption
coefficient (babs) for water-soluble brown carbon (BrC) revealed that
biomass burning emissions played a significant role in the light-absorption
properties of carbonaceous aerosols. The solar energy absorption due to
water-soluble brown carbon and EC was estimated by a calculation based on
measured light-absorbing parameters and a simulation based on a radiative
transfer model (RRTMG_SW). The solar energy absorption of
water-soluble BrC in short wavelengths (300–400 nm) was 0.8±0.4
(0.2–2.3) W m−2 (figures in parentheses represent the variation range of each parameter) from the calculation and 1.2±0.5 (0.3–1.9) W m−2 from the RRTMG_SW model. The absorption capacity of
water-soluble BrC accounted for about 20 %–30 % of the total absorption of
EC aerosols. The solar energy absorption of water-soluble BrC due to biomass
burning was estimated as 0.2±0.1 (0.0–0.9) W m−2, considering
the biomass burning contribution to carbonaceous aerosols. Potential source
contribution function model simulations showed that the solar energy
absorption induced by water-soluble BrC and EC aerosols was mostly due to
the regionally transported carbonaceous aerosols from source regions such
as southeastern China. Our results illustrate the importance of the
absorbing water-soluble brown carbon aerosols in trapping additional solar
energy in the low-level atmosphere, heating the surface and inhibiting the
energy from escaping the atmosphere.
Influence of Some Electrodeposition Parameters on Formation of Nanostructure Black Cobalt Coating used for Solar Energy Absorption
