View source for Papers:Fu et al 2012

'''Abstract |''' We simulated elemental carbon (EC) and organic
carbon (OC) aerosols in China and compared model
results to surface measurements at Chinese rural and background
sites, with the goal of deriving “top-down” emission
estimates of EC and OC, as well as better quantifying
the secondary sources of OC. We included in the model
state-of-the-science Chinese “bottom-up” emission inventories
for EC (1.92 TgC/yr) and OC (3.95 TgC/yr), as well
as updated secondary OC formation pathways. The average
simulated annual mean EC concentration at rural and background
sites was 1.1 μgC/m3, 56% lower than the observed
2.5 μgC/m3. The average simulated annual mean OC concentration
at rural and background sites was 3.4 μgC/m3,
76% lower than the observed 14 μgC/m3. Multiple regression
to fit surface monthly mean EC observations at rural
and background sites yielded the best estimate of Chinese
EC source of 3.05±0.78 TgC/yr. Based on the topdown
EC emission estimate and observed seasonal primary
OC/EC ratios, we estimated Chinese OC emissions to be
6.67±1.30 6.67±1.30 TgC/yr. Using these top-down estimates, the
simulated average annual mean EC concentration at rural and
background sites was significantly improved to 1.9 μgC/m3.
However, the model still significantly underestimated observed
OC in all seasons (simulated average annual mean OC
at rural and background sites was 5.4 μgC/m3), with little
skill in capturing the spatiotemporal variability. Secondary
formation accounts for 21% of Chinese annual mean surface
OC in the model, with isoprene being the most important precursor.
In summer, as high as 62% of the observed surface
OC may be due to secondary formation in eastern China. Our
analysis points to four shortcomings in the current bottom-up
inventories of Chinese carbonaceous aerosols: (1) the anthropogenic
source is underestimated on a national scale, particularly
for OC; (2) the spatiotemporal distributions of emissions
are misrepresented; (3) there is a missing source in
western China, likely associated with the use of biofuels or
other low-quality fuels for heating; and (4) sources in fall are
not well represented, either because the seasonal shifting of. 
emissions and/or secondary formation are poorly captured or
because specific fall emission events are missing. In addition,
secondary production of OC in China is severely underestimated.
More regional measurements with better spatiotemporal
coverage are needed to resolve these shortcomings.


'''Publication |''' '''Fu, T.-M.*''', J.J. Cao, X.Y. Zhang, S.C. Lee, Q. Zhang, Y.M. Han, W.J. Qu, Z. Han, R. Zhang, Y.X. Wang, D. Chen, and D.K. Henze (2012), Carbonaceous aerosols in China: top-down constraints on primary sources and estimation of secondary contribution, ''Atmos. Chem. Phys.'', 12, 2725-2746, doi:10.5194/acp-12-2725-2012. [http://atmoschem.org.cn/papers/Fu_et_al_2012_Atmospheric_Chemistry_and_Physics.pdf PDF]