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| Titel |
Seven year particulate matter air quality assessment from surface and satellite measurements |
| VerfasserIn |
P. Gupta, S. A. Christopher |
| 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 ; 8, no. 12 ; Nr. 8, no. 12 (2008-06-27), S.3311-3324 |
| Datensatznummer |
250006233
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| Publikation (Nr.) |
 copernicus.org/acp-8-3311-2008.pdf |
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| Zusammenfassung |
| Using seven years of the Moderate Resolution Imaging Spectroradiometer
(MODIS) aerosol optical thickness (AOT) data and ground measurements of
particulate matter mass over one site in the Southeastern United States
(33.55° N, 86.82° W) we present a comprehensive analysis of various aspects of
particulate matter air quality. Monthly, seasonal and inter-annual
relationships are examined with emphasis on sampling biases, quality
indicators in the AOT product and various cloud clearing criteria. Our
results indicate that PM2.5 mass concentration over Northern Birmingham has
decreased by about 23% in year 2006 when compared to year 2002 and air
quality during summer months was poor when compared to winter months.
MODIS-Terra AOT data was available only about 50% of the time due to
cloud cover and unfavorable surface conditions. However, the mean difference
in monthly mean PM2.5 was less than 2.2 μg m−3 derived using all
the data and from only those days when satellite AOT was available
indicating that satellite data does not have sampling issues. The
correlation between PM2.5 and MODIS AOT increased from 0.52 to 0.62 when
hourly PM2.5 data were used instead of daily mean PM2.5 data. Changing box
size for satellite data around the ground station during comparisons
produced less than ±0.03 difference in mean AOT values for 90% of
observations. Application of AOT quality flags reduced the sample size but
does not affect AOT-PM2.5 relationship significantly. We recommend using AOT
quality flags for daily analysis, whereas long time scale analysis can be
performed by using all AOT retrievals to obtain better sampling. Our
analysis indicates that satellite data is a useful tool for monitoring
particulate matter air quality especially in regions where ground
measurements are not available. While these results are representative for
the region of interest, it is difficult to extrapolate these results to a
larger context without detailed analysis using ancillary data sets. |
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