350
J. L. Moutinho et al.
the RD site was 1.3 µg m
−3 , 8.6 ppb, and 51.5 ppb respectively, while the concentration at the urban background (JST) site was 0.4 µg m
−3 , 2.8 ppb, and 16.9 ppb. The
maximum hourly concentrations were simulated when wind speeds were low and
therefore dispersion was low which often occurring at night when emissions were
also low. The wind direction measured at the RS site measured easterly winds more
than 70% of the time leading to direct influence from the highway emissions on the
monitor sites. Even though the major emissions source in the domain is the highway,
the surface streets (AADT 20,000) are an observable source [1].
55.4 Conclusion
These processes reduced unrealistically high concentrations that were observed on
and near the main highway emissions source. The linear calibration helped decrease
the bias high levels improving the average concentration fields, however hourly bias
was observed. The diurnal calibration improved both the bias high concentrations
and the distribution of the concentrations.
Acknowledgements Research described in this article was conducted under contract to the Health
Effects Institute (HEI), an organization jointly funded by the United States Environmental Protection Agency (EPA) (Assistance Award No. R-82811201) and certain motor vehicle and engine
manufacturers. The contents of this article do not necessarily reflect the views of HEI, or its sponsors, nor do they necessarily reflect the views and policies of the EPA or motor vehicle and engine
manufacturers. Atmospheric Research & Analysis, Inc. and the Georgia Department of Natural
Resources provided additional measurement data.
References
1. GA DOT, Traffic data (2012), www.dot.ga.gov/
2. HEI, Traffic-related air pollution: a critical review of the literature on emissions, exposure, and
health effects. Special Report 17 (Boston, MA, 2010)
3. M.G. Snyder, A. Venkatram, D.K. Heist, S.G. Perry, W.B. Petersen, V. Isakov, RLINE: a line
source dispersion model for near-surface releases. Atmos. Environ. 77, 748–756 (2013)
4. US EPA, Motor vehicle emissions simulator (MOVES) (2014), www.epa.gov/otaq/models/
moves/
J. L. Moutinho et al.
the RD site was 1.3 µg m
−3 , 8.6 ppb, and 51.5 ppb respectively, while the concentration at the urban background (JST) site was 0.4 µg m
−3 , 2.8 ppb, and 16.9 ppb. The
maximum hourly concentrations were simulated when wind speeds were low and
therefore dispersion was low which often occurring at night when emissions were
also low. The wind direction measured at the RS site measured easterly winds more
than 70% of the time leading to direct influence from the highway emissions on the
monitor sites. Even though the major emissions source in the domain is the highway,
the surface streets (AADT 20,000) are an observable source [1].
55.4 Conclusion
These processes reduced unrealistically high concentrations that were observed on
and near the main highway emissions source. The linear calibration helped decrease
the bias high levels improving the average concentration fields, however hourly bias
was observed. The diurnal calibration improved both the bias high concentrations
and the distribution of the concentrations.
Acknowledgements Research described in this article was conducted under contract to the Health
Effects Institute (HEI), an organization jointly funded by the United States Environmental Protection Agency (EPA) (Assistance Award No. R-82811201) and certain motor vehicle and engine
manufacturers. The contents of this article do not necessarily reflect the views of HEI, or its sponsors, nor do they necessarily reflect the views and policies of the EPA or motor vehicle and engine
manufacturers. Atmospheric Research & Analysis, Inc. and the Georgia Department of Natural
Resources provided additional measurement data.
References
1. GA DOT, Traffic data (2012), www.dot.ga.gov/
2. HEI, Traffic-related air pollution: a critical review of the literature on emissions, exposure, and
health effects. Special Report 17 (Boston, MA, 2010)
3. M.G. Snyder, A. Venkatram, D.K. Heist, S.G. Perry, W.B. Petersen, V. Isakov, RLINE: a line
source dispersion model for near-surface releases. Atmos. Environ. 77, 748–756 (2013)
4. US EPA, Motor vehicle emissions simulator (MOVES) (2014), www.epa.gov/otaq/models/
moves/