 |
| Titel |
Fossil vs. non-fossil sources of fine carbonaceous aerosols in four Chinese cities during the extreme winter haze episode of 2013 |
| VerfasserIn |
Y.-L. Zhang, R.-J. Huang, I. El Haddad, K.-F. Ho, J.-J. Cao, Y. Han, P. Zotter, C. Bozzetti, K. R. Daellenbach, F. Canonaco, J. G. Slowik, G. Salazar, M. Schwikowski, J. Schnelle-Kreis, G. Abbaszade, R. Zimmermann, U. Baltensperger, A. S. H. Prévôt, S. Szidat |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 3 ; Nr. 15, no. 3 (2015-02-06), S.1299-1312 |
| Datensatznummer |
250119392
|
| Publikation (Nr.) |
 copernicus.org/acp-15-1299-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| During winter 2013, extremely high concentrations (i.e., 4–20 times higher
than the World Health Organization guideline) of PM2.5 (particulate matter
with an aerodynamic diameter < 2.5 μm) mass concentrations (24 h samples) were
found in four major cities in China including Xi'an,
Beijing, Shanghai and Guangzhou. Statistical analysis of a combined data set
from elemental carbon (EC), organic carbon (OC), 14C and
biomass-burning marker measurements using Latin hypercube sampling allowed a
quantitative source apportionment of carbonaceous aerosols. Based on
14C measurements of EC fractions (six samples each city), we found that
fossil emissions from coal combustion and vehicle exhaust dominated EC with
a mean contribution of 75 ± 8% across all sites. The remaining
25 ± 8% was exclusively attributed to biomass combustion, consistent
with the measurements of biomass-burning markers such as anhydrosugars
(levoglucosan and mannosan) and water-soluble potassium (K+). With a
combination of the levoglucosan-to-mannosan and levoglucosan-to-K+ ratios, the major source of biomass burning in winter in China is
suggested to be combustion of crop residues. The contribution of fossil
sources to OC was highest in Beijing (58 ± 5%) and decreased from
Shanghai (49 ± 2%) to Xi'an (38 ± 3%) and Guangzhou
(35 ± 7%). Generally, a larger fraction of fossil OC was from
secondary origins than primary sources for all sites. Non-fossil sources
accounted on average for 55 ± 10 and 48 ± 9% of OC and total carbon (TC),
respectively, which suggests that non-fossil emissions were very important
contributors of urban carbonaceous aerosols in China. The primary
biomass-burning emissions accounted for 40 ± 8, 48 ± 18,
53 ± 4 and 65 ± 26% of non-fossil OC for Xi'an, Beijing,
Shanghai and Guangzhou, respectively. Other non-fossil sources excluding
primary biomass burning were mainly attributed to formation of secondary
organic carbon (SOC) from non-fossil precursors such as biomass-burning
emissions. For each site, we also compared samples from moderately to
heavily polluted days according to particulate matter mass. Despite a
significant increase of the absolute mass concentrations of primary emissions
from both fossil and non-fossil sources during the heavily polluted events,
their relative contribution to TC was even decreased, whereas the portion of
SOC was consistently increased at all sites. This observation indicates that
SOC was an important fraction in the increment of carbonaceous aerosols
during the haze episode in China. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|