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| Titel |
Radiocarbon and Organic Tracer-based Source Apportionment Study of
Carbonaceous Aerosol Collected during Two Ozone Regimes in Houston, TX, USA |
| VerfasserIn |
Subin Yoon, Sascha Usenko, Stephanie Ortiz, Adelaide Clark, Rebecca Sheesley |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147728
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| Publikation (Nr.) |
 EGU/EGU2017-11931.pdf |
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| Zusammenfassung |
| Houston is a prime study site for both primary and secondary carbonaceous organic aerosols
due to the city’s high anthropogenic activity combined with high potential for biogenic
contributions from large forested regions that are proximate to the city. During NASA’s
DISCOVER-AQ sampling campaign in Houston, TX in September 2013, fine particulate
matter (PM2.5) samples were collected and measured for fraction contemporary and fossil
carbon utilizing radiocarbon analysis. Contemporary sources can include primary and
secondary aerosol from biomass burning, biogenic sources, meat cooking, etc. Fossil sources
of carbonaceous aerosol include fossil fuel combustion, non-combustion sources and
secondary aerosol from fossil precursors. Fraction contemporary carbon of samples collected
from September 8 to 15 ranged from 45-67% with an average of 55% while samples from
September 21 to 28 ranged from 47-70% with an average of 61%, both sample sets varying
significantly. There were two different air quality regimes during the September
campaign: multi-day increases in organic carbon (OC) with low ozone, and multi-day
increases in OC with high ozone. To differentiate emission source, meteorology and
photochemistry factors in these air quality regimes, HYSPLIT back trajectory, ozone, OC,
radiocarbon and organic tracer-based chemical mass balance modeling were used. During
the last week of the campaign (September 21-28) high ozone concentration and
peak carbonaceous aerosol concentrations were observed throughout the Houston
metropolitan area. HYSPLIT back trajectory (BT) analysis also indicates a shift in air
mass contributions which corresponded to changes in radiocarbon, ozone and OC
concentrations. Daytime OC concentrations for the two different regimes are correlated with
ozone daily max at a downtown Houston site (r2 = 0.57). Daytime fossil carbon
concentrations have a higher correlation with ozone than contemporary carbon
concentrations (r2 = 0.51 and 0.32, respectively). However, contemporary carbon has a
higher correlation to OC than does fossil carbon (r2 = 0.90 and 0.81, respectively). |
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