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| Titel |
Chemical PM2.5 Speciation in Major Cities Worldwide |
| VerfasserIn |
Graydon Snider, Crystal Weagle, Michael Brauer, Aaron Cohen, Mark Gibson, Yang Liu, Vanderlei Martins, Yinon Rudich, Randall Martin |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121477
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| Publikation (Nr.) |
 EGU/EGU2016-220.pdf |
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| Zusammenfassung |
| We examined the chemical composition of fine particulate matter (PM2.5) across
13 globally dispersed urban locations (including Atlanta, Buenos Aires, Beijing,
Manila, and Dhaka), as part of the Surface PARTiculate mAtter Network (SPARTAN).
At each site sampling was conducted over 4 to 24 months for the years 2013 to
2015.
Analysis of filter samples revealed that several PM2.5 chemical components varied by
more than an order of magnitude between sites. Ammonium sulfate ranged from 2 μg m−3
(Ilorin) to 17 μg m−3 (Kanpur). Ammonium nitrate ranged from 0.2 μg m−3 (Atlanta) to 6.7
μg m−3 (Kanpur). Effective black carbon ranged from 0.4 μg m−3 (Atlanta) to 5 μg
m−3 (Dhaka and Kanpur). The all-site mean values of major PM2.5 constituents
were ammonium sulfate (20 ± 10 %), crustal material (12 ± 6.5%), effective black
carbon (10 ± 7.4 %), ammonium nitrate (3.7 ± 2.5%), sea salt (2.2 ± 1.5%), trace
element oxides (0.9 ± 0.7 %), water (7.2 ± 3.0%) and residue materials (44 ±
24%).
Based on the evaluation with collocated studies we treated residue material as mostly
organic. Major ions generally agreed well with previous studies at the same urban locations
(e.g. sulfate fractions agreed within 4% for eight out of 11 collocation comparisons).
Enhanced crustal material (CM) concentrations with high Zn:Al ratios at large cities (e.g.
Hanoi, Dhaka, Manila) imply significant anthropogenic CM contributions that deserve more
attention.
Detailed chemical speciation also aided our characterization of site-specific PM2.5 water
retention. The expected water contribution to aerosols was calculated via the hygroscopicity
parameter for each filter. Hourly PM2.5 at specified relative humidity (35%) was inferred
from nephelometer measurements of light scatter at ambient relative humidity and 9-day filter
measurements of PM2.5 mass. Our PM2.5 estimates compared favorably with a beta
attenuation monitor (BAM) at the nearby US embassy in Beijing, with a coefficient of
variation of r2 = 0.67. |
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