Environmental Engineering Reference
In-Depth Information
pollutant levels. Hence, the US EPA will deploy uncollocated SEAS in multiple
locations to support future spatial air quality studies and provide high-time
resolution data for model evaluation.
2.3. Steubenville Source Apportionment Study
Secondary sulfate, a byproduct of coal combustion, is one of the largest contributors
to air pollution in urban and rural areas. Research has shown that regional
transport of coal combustion emissions originating from the Ohio Valley region
contribute significantly to air pollution in the midwest, east and southeast (Keeler
et al., 2006). US EPA has conducted research to investigate regional, secondary
sulfate dominated PM
2.5
and mercury emissions from coal-fired power plants to
the west and southwest of Steubenville, Ohio. This study has employed multiple
receptor modeling techniques and the new APTR hybrid model. APTR results for
Steubenville, including the local and urban/regional apportionment, are shown in
Fig. 2.
The APTR analysis identified a “hot spot” south of the monitoring station
near Brilliant, Ohio. Using Google Earth, a coal-fired power plant was identified
in the vicinity of the “hot spot”. APTR will be used in future studies to examine,
quantify, and separate impacts from specific sources in complex airsheds
influenced by multiple stationary sources and high traffic roadways.
Local (38%)
Urban/Regional (62%)
Fig. 2.
Steubenville APTR Local and Urban/Regional Apportionment (bottom) and the Coal-
fired Power Plant south of Steubenville (top) identified in the APTR analysis
3. Integrating Receptor- and Source-Based Apportionment
Techniques
Source apportionment analyses can also be conducted using source-based approaches
which start with a source emission contribution, usually from an inventory, that is
input into a chemical transport model which generates an estimated concentration
at a location or locations. The integration of receptor- and source-based source can
provide increased confidence in source contribution estimates that are needed to
