Abstract Book

R. Paine, D. Heinold; AECOM, Westford, MA
U.S. EPA’s recently proposed and promulgated revisions to National Ambient Air
Quality Standards (NAAQS) for PM2.5, SO2 and NO2 provide implementation challenges
regarding the application of dispersion models to assess compliance.
Given that these new NAAQS are substantially lower than the standards they replace, the
customary degree of overestimation that is intentionally designed into the present
Modeling Guideline methods are likely to limit our ability to conduct accurate and
unbiased air quality compliance assessments. Due to the shrinking margin of compliance
associated with these new standards, the skill of regulatory models will be more severely
tested, and refined methods to incorporate background concentrations will need to be
developed. Given that long-term average PM2.5 concentrations have contributions from a
variety of near-field and more distant sources, there is a need for EPA to incorporate the
mechanisms leading to secondary particulate formation into regulatory models.
The promulgated 1-hour standard for NO2 will require more refined methods to estimate
NO to NO2 conversion over short transport distances than is provided in the AERMOD
screening-level methods. Improved methods applicable to urban areas or the vicinity of
major roadways will be required.
The proposed range of the 1-hour SO2 standard is well below the current 24-hour
NAAQS and will test the ability of dispersion models to accurately simulate peak shortterm
concentrations from point sources. Given that there is substantial variability in SO2
emissions due to variability in fuel sulfur content, statistically robust ways of accounting
for this variability need to be explored.
Use Of MODIS Satellite Measurements Of Land Use, Albedo And Leaf Area Index
In CALMET (99)
C. Bell, K. Onder, S. Lataille; Golder Associates, Calgary, AB, Canada
Recent development in the Athabasca Oil Sands Region, located in northeastern Alberta,
has drawn growing concern from stakeholders on the cumulative effects of emissions
from mining and upgrading projects on air quality. In order to assess potential cumulative
air quality changes, refined dispersion modelling is necessary.
The CALPUFF modelling system is currently the model of choice in the Oil Sands
Region. Characterizing the meteorological conditions with CALMET is dependent on
proper definition of the geophysical parameters such as land use, albedo and leaf area
index (LAI). The characterization of these parameters is important for defining the
boundary layer conditions in CALMET. In past air quality assessments completed by the
authors in the Oil Sands Region, land use was derived from the Natural Resources
Canada (NRCan) Land Cover Map of Canada1 for the year 2000 and the geophysical
parameters were assigned based on values from literature and CALMET defaults.
Recently, high temporal and spatial resolution MODerate-resolution Imaging
Spectroradiometer (MODIS) satellite data have become available. MODIS measurements
provide sufficient spectral information to extract land use, albedo and leaf area index
directly at a temporal resolution of two weeks and a spatial resolution ranging from 500
m to 1 km. This study provides a review of the geophysical parameters generated from
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