Unformatted text preview: Atmospheric Dispersion
Receptor Model Chemical Mass Balance
Hsing-Wang Li 9/13/11 03/29/2011
BLK 315 Web resources to download CMB 8.2
US EPA : ttp://www.epa.gov/ttn/scram/receptor_cmb.htm 9/13/11 Banner Page for EPA CMB8.2 YÂE 9/13/11 Input files for CMB 8.2
For each run of CMB, the model fits speciated data
from a specified group of sources (sources) to
corresponding data from a particular receptor
(1). Source PRofile selection file: PR*.sel
(2). Ambient Data (sample) selection file: AD*.sel 9/13/11 Launching EPA-CMB 8.2 YÂE 9/13/11 Select Input Files Screen ª_ ÐYÂ< Note that EPA-CMB8.2 will accept *.csv, *.dbf, and *.wks data
formats for ambient sample (AD*) and source profile (PR*) files,
which are the only input files required by the model.
9/13/11 Options 9/13/11 Options
(1)Iteration Delta: This parameter sets the maximum
number of iterations EPA-CMB8.2 will attempt to arrive
at a solution. (Must be >0; no theoretical upper limit;
default = 20)
(2)Maximum Source Uncertainty: The maximum source
uncertainty is a threshold expressed as a percentage of
the total measured mass and is adjustable via the
spinners (default = 20% ).
(3)Minimum Source Projection: The minimum source
projection is set to a default value of 0.95. 9/13/11 Options
(4)Decimal Places Displayed: The default value is 5 and
the maximum value is 6.
(5)Units: The units used for reporting results may be
changed via a pull-down menu.
(6)Output File Format: The file format for spreadsheettype output is selected in the pull-down box. As discussed
in Section 4.5, the default is ASCII (txt); commaseparated value (CSV) is also available.
(7)Britt and Luecke: Checking this box applies the Britt
and Luecke (1973) linear least squares solution that is
explained by Watson et al. (1984) when applied to CMB
(8)Source Elimination. Checking this box eliminates negative source contributions from
the calculation, one at a time.
(9)Best Fit. Checking this box causes the program to cycle through the corresponding
pairs (same array index) of fitting species and source profile arrays specified in the source
and species selection input windows until the best composite. ª_ 9/13/11 ÐYÂ< Select Ambient Data Samples ª_ ÐYÂ< one or more samples may appear selected initially. Otherwise, individual samples
are “tagged” by clicking in the respective fields under “SELECTED”.
9/13/11 View Grid YÂE 9/13/11 Select Fitting Species Fitting species are used in the calculation of source contribution estimates
9/13/11 Select Fitting Sources The user should select profiles that represent the emissions most likely to influence
9/13/11 View Grid ÂE 9/13/11 Calculation Results YÂE 9/13/11 Calculation Results
(1)When Run is invoked, EPA-CMB8.2 performs
the least-squares estimation of source contribution
estimates and performance measures on the selected
sample data using the designated fitting species and
(2)Also if more Â fitting sources than fitting species
ª_ ÐY <
have been selected, a warning appears and the user
is forced to reconfigure. 9/13/11 Main report ÂE 9/13/11 Main report
In the Main report are several information blocks
which present performance measures.
(1)First are fitting statistics: r2, P2, percent mass
explained, and degrees of freedom.
(2)Next is a block that presents the most basic
results from EPA-CMB8.2: source contribution
estimates. ª _ Ð Y Â <
(3)For each source selected is presented a source
contribution estimate (SCE) in userchosen units,
standard errors, and values for T-stat.
9/13/11 Contributions by Species 9/13/11 Contributions by Species
(1)Beyond the traditional apportionment
results generated by EPA-CMB8.2, it is also
of interest to analyze the way in which
pollutant mass is distributed among sources
by species_ Ð Y Â <
(2)The report also indicates which sources
are the major and minor contributors to each
9/13/11 Modified Pseudo-Inverse
Normalized (MPIN) Matrix The MPIN matrix identifies which fitting species have the largest influence on the
source contribution estimates from each profile
9/13/11 Source contribution estimates by CMB
model to meet following items
(3) R-Square between 0.8-1.0;
(4) Percent Mass ranging from 80-120.
(1) 9/13/11 Case Study for CMB 8.2 (1) 9/13/11 Case Study for CMB 8.2 (2) 9/13/11 Case Study for CMB 8.2 (3) 9/13/11 Thanks !
YÂE 9/13/11 ...
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- Spring '11
- Least Squares, CMB, fitting species