wAbstract
@Aerosol samples were collected during the wintertime from Nov.
24, 1998 to Feb. 12, 1999 in Beijing, China. Chemical composition
was determined using several analytical techniques, including
inductive coupled plasma atomic emission spectroscopy (ICP-AES),
graphite furnace atomic absorption spectroscopy (GFAAS) and flame
atomic absorption spectroscopy (FAAS) for trace elements, ion
chromatography (IC) for water-soluble ions and CHN elemental analyzer
for organic carbon (OC) and elemental carbon (EC). The average
concentration of aerosol was 375}169Κg m-3, ranging
from 136 to 759Κg m-3. Multilinear regression (MLR)
analysis was performed and crustal matter, secondary particles
and organics were identified as three major components of aerosol
in wintertime in Beijing, accounting for 57.3}9.8, 13.4}8.0,
and 22.8}5.9 of the total concentration, respectively. Based
on performance evaluation, Al, SO42-
and OC were selected as tracers of the three components, with
the regression coefficients of 23.5, 1.78 and 1.26, respectively.
A regression constant of 19.6 was obtained, which accounts for
other minor components in aerosol. On average 93.5 of the total
aerosol concentration, ranging from 82 to 105, was explained
by crustal matter, secondary particle and organics. Meteorological
conditions are important factors that can influence the concentration
level and chemical composition of aerosols. Wind would be favorable
for the pollutant dilution, leading to low aerosol levels, whereas
too strong a wind may cause regional soil dust and local road
dusts to be resuspended resulting in a high contribution of crustal
matter. Circuitous air movement, high RH and low wind speed facilitated
the secondary particle formation, not only inorganic salts, such
as sulfate and nitrate, but also secondary organic carbon in a
similar way.
Keywords: multilinear regression analysis; crustal component;
organic carbon; secondary particle; meteorological conditionsx
1 Introduction
2. Experimental methods
3. Results and discussion
@3.1. Concentrations and chemical compositions
@3.2. Major aerosol components identified by MLR method
@3.3. Comparison and evaluation of MLR results
@3.4. Variation of crustal component
@3.5. Variation of sulfate component
@3.6. Variation of organic component
4. Conclusions
Acknowledgments
References