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| Titel |
Characterization of near-highway submicron aerosols in New York City with a high-resolution aerosol mass spectrometer |
| VerfasserIn |
Y. L. Sun, Q. Zhang, J. J. Schwab, W.-N. Chen, M.-S. Bae, H.-M. Hung, Y.-C. Lin, N. L. Ng, J. Jayne, P. Massoli, L. R. Williams, K. L. Demerjian |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 4 ; Nr. 12, no. 4 (2012-02-29), S.2215-2227 |
| Datensatznummer |
250010748
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| Publikation (Nr.) |
 copernicus.org/acp-12-2215-2012.pdf |
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| Zusammenfassung |
| Knowledge of the variations of mass concentration, chemical composition and
size distributions of submicron aerosols near roadways is of importance for
reducing exposure assessment uncertainties in health effects studies. The
goal of this study is to deploy and evaluate an Atmospheric Sciences
Research Center-Mobile Laboratory (ASRC-ML), equipped with a suite of rapid
response instruments for characterization of traffic plumes, adjacent to the
Long Island Expressway (LIE) – a high-traffic highway in the New York City
Metropolitan Area. In total, four measurement periods, two in the morning
and two in the evening were conducted at a location approximately 30 m south
of the LIE. The mass concentrations and size distributions of non-refractory
submicron aerosol (NR-PM1) species were measured in situ at a time resolution
of 1 min by an Aerodyne High-Resolution Time-of-Flight Aerosol Mass
Spectrometer, along with rapid measurements (down to 1 Hz) of gaseous
pollutants (e.g. HCHO, NO2, NO, O3, and CO2, etc.),
black carbon (BC), and particle number concentrations and size
distributions. Particulate organics varied dramatically during periods with
high traffic influences from the nearby roadway. The variations were mainly
observed in the hydrocarbon-like organic aerosol (HOA), a surrogate for
primary OA from vehicle emissions. The inorganic species (sulfate, ammonium,
and nitrate) and oxygenated OA (OOA) showed much smoother variations
indicating minor impacts from traffic emissions. The concentration and
chemical composition of NR-PM1 also varied differently on different
days depending on meteorology, traffic intensity and vehicle types. Overall,
organics dominated the traffic-related NR-PM1 composition (>60%)
with HOA accounting for a major fraction of OA. The traffic-influenced
organics showed two distinct modes in mass-weighted size distributions,
peaking at ∼120 nm and 500 nm (vacuum aerodynamic diameter,
Dva), respectively. OOA and inorganic species appear to be internally
mixed in the accumulation mode peaking at ∼500–600 nm. The enhancement
of organics in traffic emissions mainly occurred at ultrafine mode dominated
by HOA, with little relation to the OOA-dominated accumulation mode. From
Fast Mobility Particle Sizer (FMPS) measurements, a large increase in number
concentration at ∼10 nm (mobility number mean diameter, Dm) was
also found due to traffic influence; though these particles typically
contribute a minor fraction of total particle mass. The observed rapid
variations of aerosol chemistry and microphysics may have significant
implications for near-highway air pollution characterization and exposure
assessments. |
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