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| Titel |
Sources, trends and regional impacts of fine particulate matter in southern Mississippi valley: significance of emissions from sources in the Gulf of Mexico coast |
| VerfasserIn |
M.-C. Chalbot, B. McElroy, I. G. Kavouras |
| 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 ; 13, no. 7 ; Nr. 13, no. 7 (2013-04-08), S.3721-3732 |
| Datensatznummer |
250018575
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| Publikation (Nr.) |
 copernicus.org/acp-13-3721-2013.pdf |
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| Zusammenfassung |
| The sources of fine particles over a 10 yr period at Little Rock, Arkansas,
an urban area in the southern Mississippi Valley, were identified by positive
matrix factorization. The annual trends of PM2.5 and its sources, and
their associations with the pathways of air mass backward trajectories were
examined. Seven sources were apportioned, namely, primary traffic particles,
secondary nitrate and sulphate, biomass burning, diesel particles,
aged/contaminated sea salt and mineral/road dust, accounting for more than
90% of measured PM2.5 (particles with aerodynamic diameter less than
2.5 μm) mass. The declining trend of PM2.5 mass
(0.4 μg m−3 per year) was related to lower levels of
SO42− (0.2 μg m−3 per year) due to SO2
reductions from point and mobile sources. The slower decline for NO3−
particles (0.1 μg m−3 per year) was attributed to the
increasing NH3 emissions in the Midwest. The annual variation of biomass
burning particles was associated with fires in the southeast and northwest
US. Of the four regions within 500 km from the receptor site, the Gulf Coast
and the southeast US accounted cumulatively for more than 65% of
PM2.5 mass, nitrate, sulphate and biomass burning aerosol. Overall, more
than 50% of PM2.5 and its components originated from sources outside
the state. Sources within the Gulf Coast and western Gulf of Mexico include
65% of the busiest ports in the US, intense marine traffic within 400 km
of the coast burning rich in S diesel, and a large number of offshore oil and
natural gas platforms and many refineries. This approach allowed for the
quantitative assessment of the impacts of transport from regions representing
diverse mixtures of sources and weather conditions for different types of
particles. The findings of this effort demonstrated the influences of
emission controls on SO2 and NOx on PM2.5 mass, the
potential effect of events (i.e. fires) sensitive to climate change
phenomena on air pollution and the potential of offshore activities and
shipping emissions to influence air quality in urban areas located more than
1000 km away from the sources. |
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