Technical Support Document: 

2002 CMAQ Model Performance Evaluation

 for Ozone and Particulate Matter

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Air Quality Assessment Division

Research Triangle Park, NC 27711

March 2008

Introduction

An operational model performance evaluation for ozone and PM2.5 and its
related speciated components was conducted using 2002 State/local
monitoring sites data in order to estimate the ability of the CMAQ
modeling system to replicate the base year concentrations for the 12-km
Eastern and Western United States domain .  This evaluation principally
comprises statistical assessments of model versus observed pairs that
were paired in space and time on a daily or weekly basis, depending on
the sampling frequency of each network (measured data).  For certain
time periods with missing ozone and PM2.5 observations we excluded the
CMAQ predictions from those time periods in our calculations.  It should
be noted when pairing model and observed data that each CMAQ
concentration represents a grid-cell volume-averaged value, while the
ambient network measurements are made at specific locations.  In
conjunction with the model performance statistics, we also provide
spatial plots for individual monitors of the calculated bias and error
statistics (defined below).  Statistics were generated for the 12-km
Eastern US domain (EUS), 12-km Western US domain (WUS), and five large
subregions: Midwest, Northeast, Southeast, Central, and West U.S.  The
Atmospheric Model Evaluation Tool (AMET) was used to conduct the
evaluation described in this document.

The ozone evaluation primarily focuses on observed and predicted hourly
ozone concentrations and eight-hour daily maximum ozone concentrations
at a threshold of 40ppb.  This ozone model performance was limited to
the ozone season modeled for the Ozone National Ambient Air Quality
Standard (NAAQS) Final Rule: May, June, July, August, and September. 
Ozone ambient measurements for 2002 were obtained from the Air Quality
System (AQS) Aerometric Information Retrieval System (AIRS).  A total of
1178 ozone measurement sites were included for evaluation.  The ozone
data were measured and reported on an hourly basis.

The PM2.5 evaluation focuses on PM2.5 total mass and its components
including sulfate (SO4), nitrate (NO3), total nitrate (TNO3=NO3+HNO3),
ammonium (NH4), elemental carbon (EC), and organic carbon (OC).  The
PM2.5 performance statistics were calculated for each month and season
individually and for the entire year, as a whole.  Seasons were defined
as:  winter (December-January-February), spring (March-April-May),
summer (June-July-August), and fall (September-October-November).  PM2.5
ambient measurements for 2002 were obtained from the following networks
for model evaluation:  Speciation Trends Network (STN- total of 199
sites), Interagency Monitoring of PROtected Visual Environments
(IMPROVE- total of 150 sites), and Clean Air Status and Trends Network
(CASTNet- total of 83 sites).  The pollutant species included in the
evaluation for each network are listed in Table 1-1.  For PM2.5 species
that are measured by more than one network, we calculated separate sets
of statistics for each network.  

Table 1-1. PM2.5 monitoring networks and pollutants species included in
the CMAQ performance evaluation.

Ambient Monitoring Networks 	Particulate Species

	PM2.5 Mass	SO4	NO3	TNO3	NH4	EC	OC

IMPROVE 	X 	X 	X 	 	X 	X 	X 

CASTNet 	 	X 	 	X 	X 	 	 

STN 	X 	X 	X 	 	X 	X 	X 

Note that TNO3 = (NO3 + HNO3)





	

There are various statistical metrics available and used by the science
community for model performance evaluation.  For a robust evaluation,
the principal evaluation statistics used to evaluate CMAQ performance
were two bias metrics, normalized mean bias and fractional bias; and two
error metrics, normalized mean error and fractional error.  

Normalized mean bias  SEQ CHAPTER \h \r 1  (NMB) is used as a
normalization to facilitate a range of concentration magnitudes.  This
statistic averages the difference (model - observed) over the sum of
observed values.  NMB is a useful model performance indicator because it
avoids over inflating the observed range of values, especially at low
concentrations.  Normalized mean bias is defined as:

 *100

Normalized mean error (NME) is also similar to NMB, where   SEQ CHAPTER
\h \r 1 the performance statistic is used as a normalization of the mean
error.   NME calculates the absolute value of the difference (model -
observed) over the sum of observed values.  Normalized mean error is
defined as:

 *100

Fractional bias is defined as:

 *100, where P = predicted concentrations and O = observed 

concentrations.  FB is a useful model performance indicator because it
has the advantage of equally weighting positive and negative bias
estimates.  The single largest disadvantage in this estimate of model
performance is that the estimated concentration (i.e., prediction, P) is
found in both the numerator and denominator.  Fractional error (FE) is
similar to fractional bias except the absolute value of the difference
is used so that the error is always positive.  Fractional error is
defined as:

 *100

The “acceptability” of model performance was judged by comparing our
CMAQ 2002 performance results to the range of performance found in
recent regional ozone and PM2.5 model applications (e.g., Clean Air
Interstate Rule, Final PM NAAQS Rule).  These other modeling studies
represent a wide range of modeling analyses which cover various models,
model configurations, domains, years and/or episodes, chemical
mechanisms, and aerosol modules.  Overall, the NMB, NME, FB, and FE
statistics shown in Tables A-2 thru A-10 below for CMAQ predicted 2002
ozone and PM2.5 concentrations are within the range or close to that
found in recent OAQPS applications.  The CMAQ model performance results
give us confidence that our applications of CMAQ using this 2002
modeling platform provide a scientifically credible approach for
assessing ozone and PM2.5 concentrations for the purposes of the Ozone
NAAQS Final Rule.  We discuss in the following sections the bias and
error results for the hourly ozone concentrations and eight-hour daily
maximum ozone concentrations evaluated at a threshold of 40 ppb as well
as the annual and seasonal PM2.5 and its related speciated components.

Ozone Performance Evaluation

Hourly Ozone Performance: Threshold of 40 ppb

Table 2-1 provides hourly ozone model performance statistics calculated
for a threshold of 40 ppb of observed and modeled concentrations,
restricted to the ozone season modeled for the 12-km Eastern and Western
U.S. domain and the five subregions (Midwest, Northeast, Southeast,
Central and Western U.S.).  Spatial plots of the NMB and NME statistics
(units of percent) for individual monitors are also provided as a
complement to the tabular statistical data (Figures 2-1 – 2-24). 
Hourly ozone model performance is under-predicted in both the 12-km EUS
and WUS when applying a threshold of 40 ppb for the modeled ozone season
(May-September).  For the 12-km Eastern domain, the bias and error
statistics are comparable for the aggregate of the ozone season and for
each individual ozone month modeled, with a NMB range of -1% to -10% and
a FB range of -2% to -12%, and a NME range of 16% to 18% and a FE range
of 17% to 19%.  Likewise, for the 12-km Western domain, the bias and
error statistics are similar between the ozone seasonal aggregate and
the individual months, with a NMB range of -4% to -12% and a FB range of
-5% to -15%, and a NME range of 16% to 21% and a FE range of 17% to 24%.
 Hourly ozone model performance when compared across the five subregions
shows slightly better performance in the Southeast, with NMB and FB
values ranging from -2% to -10% and NME and FE values of approximately
14% to 17%.  In general, the Northeast, Midwest, Central and West U.S.
exhibit similar bias and error statistics for the episodes modeled, NMB=
-1% to -10%; FB= -1% to -17%; NME=16% to 21%; and FE= 17% to 25%.  The
month of May shows a slightly better bias and error model performance
results, although the results are spatially and temporally comparable
across the months modeled.

Table 2-1.  CMAQ 2002 hourly ozone model performance statistics
calculated for a threshold of 40 pbb.

CMAQ 2002 Hourly Ozone:

Threshold of 40 ppb	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)

May	12-km EUS	241185	-0.7	15.9	-2.0	17.1

	12-km WUS	124931	-3.7	15.9	-5.0	17.3

	Northeast 	51055	1.2	17.1	-0.3	18.2

	Midwest 	55859	3.3	16.2	2.4	16.9

	Southeast	69073	-2.5	14.1	-3.1	14.8

	Central 	41728	-6.4	17.3	-9.2	20.3

	West	111385	-3.9	16.1	-5.2	17.6

June	12-km EUS	256263	-7.5	16.8	-9.0	18.6

	12-km WUS	125662	-8.37	17.7	-9.3	19.1

	Northeast	61354	-8.46	17.3	-9.9	19.1

	Midwest	54515	-7.19	17.9	-8.3	19.6

	Southeast	67867	-7.2	15.3	-7.6	16.3

	Central 	46026	-10.0	17.5	-13.5	21.2

	West	109157	-8.8	18.2	-9.9	19.7

July	12-km EUS	257076	-5.3	17.7	-6.6	19.2

	12-km WUS	116785	-12.0	21.5	-14.9	24.3

	Northeast	66774	-3.9	17.0	-4.8	18.0

	Midwest	59360	-10.5	19.4	-12.3	21.7

	Southeast	68619	-3.6	16.5	-3.9	17.2

	Central	36021	-3.6	18.7	-6.3	21.1

	West	104321	-13.6	21.8	-16.8	24.9

August	12-km EUS	235090	-8.7	17.8	-10.2	19.7

	12-km WUS	125575	-7.91	20.1	-10.2	22.1

	Northeast	53837	-6.4	16.7	-7.4	18.0

	Midwest	54179	-10.8	19.1	-12.4	21.4

	Southeast	62506	-9.4	17.3	-9.9	18.5

	Central	41456	-9.3	18.7	-12.8	22.4

	West	110225	-8.5	20.6	-11.1	22.8

September	12-km EUS	179156	-9.9	17.2	-11.8	19.5

	12-km WUS	99710	-10.7	19.0	-12.7	21.1

	Northeast	44678	-8.7	16.3	-10.6	18.4

	Midwest	34285	-11.4	18.5	-12.9	20.4

	Southeast	41627	-8.2	16.5	-9.0	17.8

	Central 	41549	-12.8	18.8	-16.6	22.8

	West	83921	-11.7	20.0	-13.8	22.1

Seasonal Aggregate	12-km EUS	1168770	-6.4	17.1	-7.7	18.8

	12-km WUS 	592663	-8.4	18.8	-10.3	20.7

	Northeast	277698	-5.4	16.9	-6.5	18.4

	Midwest	258198	-7.3	18.3	-8.4	20.0

	Southeast	309692	-6.0	15.9	-6.4	16.8

	Central U	206780	-8.6	18.2	-11.9	21.6

	West	519009	-9.2	19.3	-11.2	21.3



           

Figure 2-1.  Normalized Mean Bias (%) of hourly ozone (40 ppb threshold)
by monitor for 12-km Eastern U.S. domain, May 2002.

Figure 2-2.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, May 2002.

Figure 2-3.  Normalized Mean Bias (%) of hourly ozone (40 ppb threshold)
by monitor for 12-km Eastern U.S. domain, June 2002.

Figure 2-4.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, June 2002.

Figure 2-5.  Normalized Mean Bias (%) of hourly ozone (40 ppb threshold)
by monitor for 12-km Eastern U.S. domain, July 2002.

Figure 2-6.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, July 2002.

Figure 2-7.  Normalized Mean Bias (%) of hourly ozone (40 ppb threshold)
by monitor for 12-km Eastern U.S. domain, August 2002.

Figure 2-8.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, August 2002.

Figure 2-9.  Normalized Mean Bias (%) of hourly ozone (40 ppb threshold)
by monitor for 12-km Eastern U.S. domain, September 2002.

Figure 2-10.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, September 2002.

Figure 2-11.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, seasonal aggregate
2002.

Figure 2-12.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Eastern U.S. domain, seasonal aggregate
2002.

Figure 2-13.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, May 2002.

Figure 2-14.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, May 2002.

Figure 2-15.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, June 2002.

Figure 2-16.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, June 2002.

Figure 2-17.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, July 2002.

Figure 2-18.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, July 2002.

Figure 2-19.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, August 2002.

Figure 2-20.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, August 2002.

Figure 2-21.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, September 2002.

Figure 2-22.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, September 2002.

Figure 2-23.  Normalized Mean Bias (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, seasonal aggregate
2002.

Figure 2-24.  Normalized Mean Error (%) of hourly ozone (40 ppb
threshold) by monitor for 12-km Western U.S. domain, seasonal aggregate
2002.

Eight-hour Ozone Performance: Threshold of 40 ppb

Table 2-2 presents eight-hour daily maximum ozone model performance bias
and error statistics for the entire range of observed and modeled
concentrations at a threshold of 40 ppb for the ozone season modeled for
the 12-km Eastern and Western U.S. domain and the corresponding
subregions defined above.  Spatial plots of the NMB and NME statistics
(units of percent) for individual monitors based on the aggregate and
the individual ozone months modeled respectively are shown in Figures
2-25 through  2-48.  In general, CMAQ slightly under-predicts
eight-hourly daily maximum ozone with a threshold of 40 ppb, which also
exhibits better model performance than the ozone hourly analysis for
these modeled time periods.  For the 12-km Eastern domain, the bias
statistics are within the range of approximately -1% to -6%, while the
error statistics range from 12% to 13% for the aggregate of the ozone
season and for most of the months modeled.  There was a slight
over-prediction of eight-hour daily maximum ozone in the month of May
(bias of approximately 4%).  For the 12-km Western domain, the bias
statistics are within the range of approximately 0% to -%, while the
error statistics range from 12% to 13% for the aggregate of the ozone
season and for the individual months modeled.  The Southeast region
shows good model performance with bias and error statistics
approximately -1% and 13%, respectively.  The five subregions show
relatively similar eight-hour daily maximum ozone performance, with bias
values ranging from 0% to -8% and error values ranging from 11% to 17%. 
  

Table 2-2.  CMAQ 2002 eight-hour daily maximum ozone model performance
statistics calculated for a threshold of 40 pbb.

CMAQ 2002 Eight-Hour Maximum Ozone:

Threshold of 40 ppb	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)

May	12-km EUS	19172	3.9	12.7	4.3	12.6

	12-km WUS	9223	0.2	12.6	0.6	12.8

	Northeast	4255	6.7	14.3	6.8	14.2

	Midwest	4198	7.8	13.7	8.2	13.5

	Southeast	5470	0.6	10.9	1.1	11.0

	Central 	3379	0.3	12.3	0.7	12.4

	West	8155	-0.1	12.8	0.3	12.9

June	12-km EUS	19462	-3.9	12.3	-3.3	12.4

	12-km WUS	9029	-4.9	14.1	-4.2	14.2

	Northeast	4608	-5.3	12.5	-4.7	12.7

	Midwest	4104	-3.2	12.7	-2.2	12.8

	Southeast	5110	-4.8	11.8	-4.1	11.9

	Central 	3603	-4.5	12.2	-4.4	12.7

	West	7818	-5.3	14.5	-4.7	14.7

July	12-km EUS	20565	-1.6	13.5	-1.0	13.6

	12-km WUS	8809	-7.4	17.1	-8.1	18.0

	Northeast	5380	-0.7	13.0	-0.2	12.9

	Midwest	4368	-6.5	14.2	-5.8	14.4

	Southeast	5633	-0.9	13.0	-0.1	13.0

	Central 	3114	1.3	14.4	1.2	14.7

	West	7784	-9.0	17.2	-9.9	18.2

August	12-km EUS	19260	-5.1	13.2	-4.4	13.4

	12-km WUS	9551	-2.8	15.8	-3.1	16.1

	Northeast	4667	-2.9	12.4	-2.2	12.4

	Midwest	4012	-8.1	13.9	-7.5	14.2

	Southeast	5067	-6.4	13.4	-5.4	13.4

	Central 	3543	-4.0	13.5	-3.9	14.1

	West	8311	-3.2	16.1	-3.6	16.5

September	12-km EUS	15865	-6.2	12.6	-5.9	12.9

	12-km WUS	8185	-6.7	15.0	-6.9	15.5

	Northeast	4074	-6.0	11.8	-6.0	12.3

	Midwest	3120	-7.2	13.3	-6.5	13.3

	Southeast	3671	-4.5	12.6	-3.8	12.7

	Central	3492	-8.5	13.8	-8.7	14.5

	West	6911	-7.3	15.9	-7.6	16.4

Seasonal Aggregate	12-km EUS	94324	-2.6	12.9	-1.9	13.0

	12-km WUS	44797	-4.3	14.9	-4.2	15.3

	Northeast	22984	-1.9	12.8	-1.2	12.9

	Midwest	19802	-3.6	13.6	-2.5	13.7

	Southeast	24951	-3.1	12.4	-2.3	12.4

	Central 	17131	-3.3	13.2	-3.1	13.7

	West	38979	-4.9	15.3	-5.0	15.7



Figure 2-25.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Eastern U.S. domain, May 2002.

Figure 2-26.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Eastern U.S. domain, May
2002.

Figure 2-27.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Eastern U.S. domain, June 2002.

Figure 2-28.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Eastern U.S. domain, June
2002.

Figure 2-29.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Eastern U.S. domain, July 2002.

Figure 2-30.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Eastern U.S. domain, July
2002.

Figure 2-31.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Eastern U.S. domain, August
2002.

Figure 2-32.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Eastern U.S. domain,
August 2002.

Figure 2-33.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Eastern U.S. domain, September
2002.

Figure 2-34.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Eastern U.S. domain,
September 2002.

Figure 2-35.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Eastern U.S. domain, seasonal
aggregate 2002.

Figure 2-36.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Eastern U.S. domain,
seasonal aggregate 2002.

Figure 2-37.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Western U.S. domain, May 2002.

Figure 2-38.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Western U.S. domain, May
2002.

Figure 2-39.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Western U.S. domain, June 2002.

Figure 2-40.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Western U.S. domain, June
2002.

Figure 2-41.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Western U.S. domain, July 2002.

Figure 2-42.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for Western U.S., July 2002.

Figure 2-43.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Western U.S. domain, August
2002.

Figure 2-44.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Western U.S. domain,
August 2002.

Figure 2-45.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Western U.S. domain, September
2002.

Figure 2-46.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for 12-km Western U.S. domain,
September 2002.

Figure 2-47.  Normalized Mean Bias (%) of eight-hour daily maximum ozone
(40 ppb threshold) by monitor for 12-km Western U.S. domain, seasonal
aggregate 2002.

Figure 2-48.  Normalized Mean Error (%) of eight-hour daily maximum
ozone (40 ppb threshold) by monitor for Western U.S., seasonal aggregate
2002.

PM2.5 Species Performance Evaluation

Annual PM2.5 Species Performance

Table 3-1 provides annual model performance statistics for PM2.5 and its
component species for the 12-km Eastern domain, 12-km Western domain,
and five subregions defined above (Midwest, Northeast, Southeast,
Central, and West U.S.).  Spatial plots of the NMB and NME statistics
(units of percent) for individual monitors are also provided in Figures
3-1 – 3-28.  In the East, annual total PM2.5 mass is over-predicted
when compared at STN sites (bias of ~11% and error of ~43%) and
under-predicted when compared at IMPROVE site (bias of ~ -2% and error
of ~ 50%).  In the West, annual total PM2.5 mass is under-predicted when
evaluated at STN sites and IMPROVE sites, with better performance at STN
network (bias ~ -6).  Although not shown here, the mean observed
concentrations of PM2.5 are approximately twice as high at the STN sites
(EUS = ~13µg m-3; WUS = ~12µg m-3) as the IMPROVE sites (EUS = ~6µg
m-3; WUS = ~4µg m-3), thus illustrating the statistical differences
between the urban STN and rural IMPROVE networks.  Sulfate is
consistently under-predicted at STN, IMPROVE, and CASTNet sites, with
NMB values ranging from -26% to -3%.  Overall, sulfate performance is
best in the East at urban STN sites (NMB =   -4% and NME = 33%). 
Nitrate is over-predicted in the 12-km Eastern domain (NMB in the range
of 18% to 48%), while nitrate is under-predicted in the 12-km Western
domain (NMB in the range of -34% to -45%).  Likewise, model performance
of total nitrate at CASTNet sites shows an over-prediction in the East
(NMB = 24%) and an under-prediction in the West (NMB = -20%).  Ammonium
model performance varies across the STN and CASTNet in the East and
West, with an over-prediction in the Eastern domain and an
under-prediction in the West.  Elemental carbon is over-predicted at STN
sites in the East and West with a NMB of ~44%, FB of ~20%, NME of ~80%,
and FE of ~60%.  Although, EC is under-predicted at IMPROVE sites in the
East and West with a NMB of ~ -15%, FB of ~ -25%, NME of ~55%, and FE of
~55%.  Organic carbon is moderately under-predicted for all domains in
the STN and IMPROVE networks (bias ~ -35% and error ~ 60%.  Differences
in model predictions between IMPROVE and STN networks could be
attributed to both the rural versus urban characteristics as well as
differences in the measurement methodology between the two networks
(e.g. blank correction factors, and filter technology used).     

Table 3-1.  2002 CMAQ annual PM2.5 species model performance statistics.

CMAQ 2002 Annual	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	PM2.5                                       Total Mass	STN	12-km EUS
10307	10.8	42.8	5.4	42.6



12-km WUS	3000	-5.8	46.9	-3.1	45.0



Northeast	1516	14.9	35.6	13.2	34.4



Midwest	2780	20.5	48.2	16.6	42.6



Southeast	2554	-3.9	36.0	-10.0	39.7



Central 	2738	14.5	49.1	6.0	49.4



West	2487	-7.4	46.8	-4.5	44.8

	IMPROVE	12-km EUS	8436	-2.3	49.0	-5.7	51.4



12-km WUS	10123	-26.4	53.5	-26.3	57.5



Northeast	592	8.6	41.5	2.4	41.0



Midwest	2060	21.0	59.4	17.4	51.6



Southeast	1803	-13.1	41.2	-19.8	49.9



Central 	1624	-13.1	49.4	-17.6	57.0



West	9543	-27.8	53.1	-27.1	57.2

Sulfate	STN	12-km EUS	10157	-3.9	33.6	-9.7	38.4



12-km WUS	2926	-20.6	41.9	-12.2	43.5



Northeast	1487	3.6	34.9	-2.9	36.2



Midwest	2730	-4.3	29.1	-8.8	33.6



Southeast	2541	-7.6	33.4	-16.3	38.8



Central	2686	-3.2	39.2	-7.2	44.3



West	2446	-26.1	44.9	-15.8	44.8

	IMPROVE	12-km EUS	8532	-10.8	33.0	-7.2	40.6



12-km WUS	10232	-7.5	42.4	7.6	45.7



Northeast	597	-4.9	29.9	-10.0	35.7



Midwest	2070	-12.3	30.1	-9.9	36.1



Southeast	1805	-9.5	32.9	-16.8	40.5



Central 	1671	-16.1	35.0	-16.0	42.4



West	9645	-5.5	43.5	8.6	45.9

	CASTNet	12-km EUS	3173	-11.3	20.5	-16.3	26.1



12-km WUS	1158	-21.3	34.6	-11.2	35.9



Northeast	663	-8.3	19.3	-16.3	24.3



Midwest	839	-12.3	17.9	-15.6	21.6



Southeast	1085	-11.2	21.5	-17.8	27.2



Central 	229	-20.7	27.3	-27.4	33.6



West	1118	-20.4	35.3	-10.7	36.1

Nitrate	STN	12-km EUS	8770	18.3	65.9	-29.1	84.5



12-km WUS	2726	-45.0	63.1	-70.6	95.0



Northeast	1488	17.4	59.1	-5.0	67.3



Midwest	2731	32.7	70.4	-10.9	78.1



Southeast	2540	8.6	84.6	-64.7	107.5



Central 	1298	12.7	52.5	-13.4	69.1



West	2446	-47.5	62.8	-73.8	95.4

	IMPROVE	12-km EUS	8514	48.4	106.8	-52.8	116.4



12-km WUS	10110	-34.8	80.67	-101.0	130.0



Northeast	597	43.0	86.0	-37.0	102.8



Midwest	2069	122.2	153.8	3.5	107.5



Southeast	1803	33.5	112.2	-78.5	130.8



Central 	1672	18.1	81.0	-59.6	114.1



West	9522	-39.6	81.1	-104.0	131.1

Total Nitrate  (NO3+HNO3)	CASTNet	12-km EUS	3171	24.4	37.3	16.8	35.1



12-km WUS	1157	-19.5	44.2	-12.0	46.0



Northeast	662	20.5	29.4	16.3	25.3



Midwest	839	39.1	46.5	29.0	39.7



Southeast	1085	22.9	39.5	15.8	37.2



Central 	229	6.2	35.6	0.6	36.2



West	1117	-20.4	45.8	-12.1	46.6

Ammonium	STN	12-km EUS	10157	11.9	40.6	14.4	45.2



12-km WUS	2926	-23.6	55.7	7.2	58.1



Northeast	1488	16.0	39.6	21.8	42.8



Midwest	2731	12.3	38.4	19.2	42.4



Southeast	2540	7.3	38.4	6.0	41.8



Central 	2685	15.0	46.6	14.3	52.1



West	2446	-30.6	56.7	2.9	59.7

	CASTNet	12-km EUS	3166	5.3	30.8	2.7	31.6



12-km WUS	1156	-16.8	42.5	-13.0	41.1



Northeast	661	15.3	27.6	13.6	25.2



Midwest	837	9.8	34.7	11.9	33.9



Southeast	1085	-7.7	30.1	-9.7	33.6



Central 	229	7.4	33.1	3.0	35.6



West	1116	-21.1	43.5	-14.4	41.4

Elemental Carbon	STN	12-km EUS	10031	45.0	78.9	22.1	56.9



12-km WUS	2975	43.1	82.6	18.2	61.3



Northeast	1498	37.1	58.9	24.5	48.3



Midwest	2744	53.1	76.7	26.3	54.7



Southeast	2506	16.9	66.0	7.2	51.7



Central 	2570	91.7	118.0	41.0	68.1



West	2475	49.0	86.2	17.1	62.7

	IMPROVE	12-km EUS	8282	-15.0	49.2	-23.4	52.8



12-km WUS	10069	-14.1	67.2	-29.5	62.1



Northeast	599	-22.6	37.5	-27.4	46.5



Midwest	2056	11.6	57.5	0.5	50.8



Southeast	1795	-32.4	44.6	-42.0	55.6



Central 	1532	-24.3	47.6	-29.8	55.9



West	9493	-15.5	67.8	-31.3	62.7

Organic Carbon	STN	12-km EUS	9726	-39.9	58.0	-41.1	70.5



12-km WUS	2903	-37.6	60.3	-40.4	69.3



Northeast	1447	-45.2	60.9	-41.6	73.1



Midwest	2641	-26.5	61.7	-19.7	67.6



Southeast	2474	-47.4	55.3	-53.7	70.7



Central 	2504	-43.6	54.0	-51.3	69.7



West	2408	-36.3	61.4	-37.9	70.2

	IMPROVE	12-km EUS	8287	-32.4	60.5	-37.1	67.9



12-km WUS	10082	-34.8	60.0	-31.2	63.0



Northeast	598	-42.4	54.8	-40.2	63.8



Midwest	2057	-6.4	68.2	-0.7	60.8



Southeast	1800	-46.1	58.4	-69.7	81.3



Central	1531	-47.9	61.6	-61.2	79.6



West	9508	-34.5	59.6	-29.7	61.9



Figure 3-1.  Normalized Mean Bias (%) of annual PM2.5 by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-2.  Normalized Mean Error (%) of annual PM2.5 by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-3.  Normalized Mean Bias (%) of annual sulfate by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-4.  Normalized Mean Error (%) of annual sulfate by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-5.  Normalized Mean Bias (%) of annual nitrate by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-6.  Normalized Mean Error (%) of annual nitrate by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-7.  Normalized Mean Bias (%) of annual total nitrate by monitor
for 12-km Eastern U.S. domain, 2002.

Figure 3-8.  Normalized Mean Error (%) of annual total nitrate by
monitor for 12-km Eastern U.S. domain, 2002.

Figure 3-9.  Normalized Mean Bias (%) of annual ammonium by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-10.  Normalized Mean Error (%) of annual ammonium by monitor
for 12-km Eastern U.S. domain, 2002.

Figure 3-11.  Normalized Mean Bias (%) of annual EC by monitor for 12-km
Eastern U.S. domain, 2002.

Figure 3-12.  Normalized Mean Error (%) of annual EC by monitor for
12-km Eastern U.S. domain. 2002.

Figure 3-13.  Normalized Mean Bias (%) of annual OC by monitor for 12-km
Eastern U.S. domain, 2002.

Figure 3-14.  Normalized Mean Error (%) of annual OC by monitor for
12-km Eastern U.S. domain, 2002.

Figure 3-15.  Normalized Mean Bias (%) of annual PM2.5 by monitor for
12-km Western U.S. domain, 2002.

Figure 3-16.  Normalized Mean Error (%) of annual PM2.5 by monitor for
12-km Western U.S. domain, 2002.

Figure 3-17.  Normalized Mean Bias (%) of annual sulfate by monitor for
12-km Western U.S. domain, 2002.

Figure 3-18.  Normalized Mean Error (%) of annual sulfate by monitor for
12-km Western U.S. domain, 2002.

Figure 3-19.  Normalized Mean Bias (%) of annual nitrate by monitor for
12-km Western U.S. domain, 2002.

Figure 3-20.  Normalized Mean Error (%) of annual nitrate by monitor for
12-km Western U.S. domain, 2002.

Figure 3-21.  Normalized Mean Bias (%) of annual total nitrate by
monitor for 12-km Western U.S. domain, 2002.

Figure 3-22.  Normalized Mean Error (%) of annual total nitrate by
monitor for 12-km Western U.S. domain, 2002.

Figure 3-23.  Normalized Mean Bias (%) of annual ammonium by monitor for
12-km Western U.S. domain, 2002.

Figure 3-24.  Normalized Mean Error (%) of annual ammonium by monitor
for 12-km Western U.S. domain, 2002.

Figure 3-25.  Normalized Mean Bias (%) of annual EC by monitor for 12-km
Western U.S. domain, 2002.

Figure 3-26.  Normalized Mean Error (%) of annual EC by monitor for
12-km Western U.S. domain, 2002.

Figure 3-27.  Normalized Mean Bias (%) of annual OC by monitor for 12-km
Western U.S. domain, 2002.

Figure 3-28.  Normalized Mean Error (%) of annual OC by monitor for
12-km Western U.S. domain, 2002.

Seasonal PM2.5 Total Mass Performance

Seasonal model performance statistics for PM2.5 total mass are shown in
Table 3-2.  Figures 3-29 to 3-44 depict spatial plots of the NMB and NME
statistics (units of percent) for individual monitors.  Total PM2.5 mass
is generally over-predicted in the cooler seasons (winter and fall) in
the 12-km Eastern domain for both STN and IMPROVE networks.  In the fall
season, PM2.5 is slightly over-predicted for Eastern STN and IMPROVE
networks with NMB values ranging from 10% to 15% and FB values ranging
from 6% to 9%.  In the winter season, PM2.5 is moderately over-predicted
for Eastern STN and IMPROVE networks with NMB values ranging from 47% to
55% and FB values ranging from 60% to 72%.  In the 12-km Western domain,
PM2.5 is over-predicted in the winter (NMB in the range of 2% to 14%),
whereas PM2.5 is under-predicted in the fall (NMB in the range of -15%
to -4%).  In the spring, CMAQ over-predicts PM2.5 in the East (NMB=15%)
and West (NMB=4%) for urban STN sites.  However, PM2.5 is
under-predicted for rural IMPROVE sites in the East (NMB= -2%) and West
(NMB= -32%).  Note that for comparison of West versus East STN sites,
the total number of Western sites is usually less than a third of the
Eastern sites.  In the summer season, PM2.5 is under-predicted in the
East and West for STN and IMPROVE. 

Table 3-2.  CMAQ 2002 seasonal model performance statistics for PM2.5
total mass.

CMAQ 2002 PM2.5 total mass	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	Winter	STN	12-km EUS	2185	47.1	60.1	34.5	50.0



12-km WUS	637	2.17	53.4	8.5	51.1



Northeast	299	32.6	45.2	31.1	43.4



Midwest	582	74.2	77.6	55.1	57.9



Southeast	527	24.5	45.9	15.0	42.2



Central 	619	51.6	66.2	36.0	53.6



West	534	-1.6	51.8	3.9	50.4

	IMPROVE	12-km EUS	2068	55.0	72.2	36.9	56.4



12-km WUS	2467	13.7	59.5	11.1	54.3



Northeast	148	35.7	46.7	25.1	41.3



Midwest	514	110.5	115.7	70.5	74.4



Southeast	450	22.3	46.7	13.3	46.0



Central 	381	31.5	57.9	21.9	53.8



West	2340	11.1	58.6	10.1	54.0

Spring	STN	12-km EUS	2452	15.3	46.2	6.9	42.8



12-km WUS	694	3.6	50.6	5.1	45.3



Northeast	366	31.1	51.7	20.6	41.0



Midwest	630	33.2	47.3	23.1	38.2



Southeast	628	-0.2	35.3	-5.9	36.8



Central 	652	4.1	52.5	-6.1	54.2



West	590	9.7	51.0	9.6	44.6

	IMPROVE	12-km EUS	1912	-1.7	46.9	-12.5	46.7



12-km WUS	2390	-31.7	50.3	-35.4	55.7



Northeast	147	33.1	56.3	8.2	43.4



Midwest	510	28.4	48.6	16.3	39.9



Southeast	440	-13.6	40.9	-22.6	47.3



Central 	289	-24.7	52.7	-38.8	61.0



West	2331	-30.4	49.7	-34.5	55.1

Summer	STN	12-km EUS	2798	-17.3	33.1	-22.3	40.7



12-km WUS	841	-22.9	37.9	-24.7	42.6



Northeast	418	-6.3	24.9	-7.6	27.6



Midwest	780	-18.6	33.5	-16.3	36.1



Southeast	698	-24.2	34.2	-34.1	43.9



Central 	713	-13.4	37.0	-21.3	47.8



West	688	-23.0	39.4	-24.8	43.9

	IMPROVE	12-km EUS	2160	-38.1	42.9	-52.5	58.9



12-km WUS	2572	-46.5	55.0	-60.8	68.0



Northeast	149	-25.3	32.1	-36.7	43.1



Midwest	516	-33.7	40.3	-35.4	47.5



Southeast	454	-37.5	42.4	-55.8	62.1



Central 	440	-43.0	45.5	-65.1	68.0



West	2412	-46.3	55.5	-60.1	67.7

Fall	STN	12-km EUS	2872	15.5	39.0	9.2	38.6



12-km WUS	828	-4.1	46.4	3.2	42.6



Northeast	433	16.4	29.7	14.7	29.3



Midwest	788	26.9	46.6	15.4	41.3



Southeast	701	-2.1	32.0	-8.6	36.4



Central 	754	25.2	46.0	17.8	43.2



West	675	-10.1	45.2	-2.6	41.7

	IMPROVE	12-km EUS	2296	9.6	42.5	5.6	43.6



12-km WUS	2694	-15.8	50.7	-19.5	52.1



Northeast	148	20.1	39.1	13.3	36.1



Midwest	520	23.8	48.6	18.5	44.4



Southeast	459	-3.3	35.3	-14.0	44.0



Central 	514	8.6	47.2	5.6	47.6



West	2460	-20.9	49.4	-23.2	51.9



Figure 3-29.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure 3-30.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure 3-31.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-32.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-33.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-34.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain. Summer 2002.

Figure 3-35.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-36.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-37.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-38.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-39.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-40.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-41.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-42.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-43.  Normalized Mean Bias (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Fall 2002.

Figure 3-44.  Normalized Mean Error (%) of PM2.5 by monitor for 12-km
Western U.S. domain, Fall 2002.

Seasonal Sulfate Performance

As seen in Table 3-3, CMAQ generally under-predicts sulfate in the 12-km
Eastern and Western domains throughout the entire year.  Figures 3-45
– 3-60 show spatial plots of the NMB and NME statistics (units of
percent) for individual monitors as a complement to the tabular
statistical data.  Sulfate predictions during the winter season show NMB
values ranging from -7% to -18% and FB values ranging from 6% to -17% in
the East and with NMB values ranging from -8% to -33% and FB values
ranging from 0.3% to -41% in the West.  Sulfate predictions during the
fall seasons are nearly unbiased in the East, with NMB values ranging
from 3% to -10% across STN, IMPROVE, and CASTNet networks.  Sulfate is
moderately under-predicted in the West during the fall season (NMB
values ranging from 11% to 22%).  In the spring, sulfate predictions are
somewhat under-predicted in the East and West, with NMB values ranging
from -4% to -18%.  Sulfate predictions during the summer season are
slightly under-predicted in the East across the available monitoring
data, while sulfate predictions in the West were moderately
under-predicted.

Table 3-3.  CMAQ 2002 seasonal model performance statistics for sulfate.

CMAQ 2002 Sulfate	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	Winter	STN	12-km EUS	2155	-6.8	35.1	-8.8	38.6



12-km WUS	633	-8.5	49.2	0.3	47.4



Northeast	286	-6.8	34.6	-12.0	37.1



Midwest	575	-4.1	29.3	-6.7	30.4



Southeast	523	-16.0	34.9	-22.7	41.1



Central 	614	0.9	43.2	1.5	45.2



West	531	-14.4	49.1	-5.6	46.8

	IMPROVE	12-km EUS	2073	-8.1	36.2	6.4	45.7



12-km WUS	2484	33.5	61.1	41.5	58.3



Northeast	149	-17.4	35.3	-24.3	40.1



Midwest	514	-9.3	30.1	-9.6	32.8



Southeast	447	-13.5	31.5	-15.2	38.2



Central 	383	-10.0	39.7	0.8	45.2



West	2356	36.1	63.6	42.2	58.9

	CASTNet	12-km EUS	711	-17.8	25.3	-17.5	30.4



12-km WUS	253	11.4	37.3	21.4	37.5



Northeast	154	-23.3	29.3	-31.6	35.8



Midwest	184	-16.9	22.2	-20.0	26.4



Southeast	249	-15.7	23.2	-16.9	25.8



Central 	41	-19.2	25.8	-21.7	30.2



West	249	12.8	38.4	21.8	37.8

Spring	STN	12-km EUS	2396	-13.4	35.5	-16.5	38.8



12-km WUS	667	-14.5	37.3	-2.6	37.3



Northeast	362	-2.7	39.1	-8.7	39.5



Midwest	609	-5.4	34.7	-10.7	34.8



Southeast	624	-18.2	32.1	-20.1	36.3



Central 	626	-21.1	39.2	-22.2	45.0



West	586	-14.6	38.4	-2.6	37.8

	IMPROVE	12-km EUS	1946	-16.0	32.9	-15.0	38.0



12-km WUS	2412	-4.3	38.8	8.3	40.6



Northeast	147	-10.7	30.2	-13.9	34.3



Midwest	512	-10.5	32.7	-14.1	36.3



Southeast	441	-16.1	30.6	-20.2	37.1



Central 	307	-29.8	36.9	-33.9	44.4



West	2350	-1.8	38.7	9.6	40.4

	CASTNet	12-km EUS	784	-17.6	23.4	-20.4	27.1



12-km WUS	289	-18.2	29.8	-12.3	30.3



Northeast	169	-13.5	20.6	-17.0	23.8



Midwest	203	-13.2	20.2	-16.7	22.5



Southeast	267	-20.8	24.7	-24.6	29.1



Central 	55	-37.8	38.3	-43.9	45.3



West	280	-16.9	29.6	-11.5	30.1

Summer	STN	12-km EUS	2768	1.6	31.4	-3.6	37.8



12-km WUS	805	-27.7	40.5	-25.1	45.6



Northeast	414	15.3	34.8	13.2	33.8



Midwest	770	-1.1	26.8	1.0	32.7



Southeast	697	0.7	33.1	-6.9	37.8



Central 	701	-3.3	35.3	-13.0	46.3



West	660	-35.4	46.8	-28.4	48.9

	IMPROVE	12-km EUS	2208	-11.1	32.0	-13.6	41.0



12-km WUS	2639	-21.0	41.1	-14.8	43.3



Northeast	152	0.9	28.2	1.6	35.7



Midwest	526	-13.4	29.6	-1.3	39.8



Southeast	456	-7.9	33.6	-17.8	43.8



Central	461	-17.1	33.4	-27.5	45.3



West	2475	-19.4	42.1	-13.3	43.0

	CASTNet	12-km EUS	868	-6.8	17.6	-12.9	22.9



12-km WUS	313	-32.5	37.9	-32.5	41.4



Northeast	176	-0.03	16.0	-1.2	16.1



Midwest	233	-10.5	16.1	-12.3	19.0



Southeast	298	-6.6	18.6	-14.5	26.8



Central 	68	-15.3	23.5	-22.4	31.1



West	299	-33.1	39.4	-32.6	41.9

Fall	STN	12-km EUS	2838	-2.7	34.5	-10.6	38.6



12-km WUS	821	-22.4	42.8	-17.1	43.5



Northeast	425	-4.0	32.1	-7.5	35.2



Midwest	776	-9.6	28.4	-18.7	36.0



Southeast	697	-5.3	34.1	-17.4	40.4



Central	745	9.7	41.9	3.8	40.9



West	669	-30.5	44.8	-23.0	45.3

	IMPROVE	12-km EUS 	2305	-7.4	32.6	-6.6	38.1



12-km WUS	2697	-11.4	38.6	-2.4	41.0



Northeast	149	-2.4	29.3	-3.6	32.6



Midwest	518	-14.4	28.4	-14.8	35.4



Southeast	461	-3.3	34.8	-14.1	42.6



Central 	520	-8.2	34.2	-7.6	36.7



West	2464	-11.6	39.9	-2.4	41.5

	CASTNet	12-km EUS	810	-9.6	20.0	-14.8	24.6



12-km WUS	303	-21.8	33.3	-15.6	34.2



Northeast	164	-10.2	18.0	-17.6	22.9



Midwest	219	-12.0	16.7	-14.6	19.5



Southeast	271	-7.1	22.2	-15.3	27.1



Central 	65	-14.9	24.1	-22.4	28.3



West	290	-21.5	34.1	-15.2	34.4



Figure 3-45.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure 3-46.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure 3-47.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-48.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-49.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-50.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-51.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-52.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-53.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-54.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-55.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-56.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-57.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-58.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-59.  Normalized Mean Bias (%) of sulfate by monitor for 12-km
Western U.S. domain, Fall 2002.

Figure 3-60.  Normalized Mean Error (%) of sulfate by monitor for 12-km
Western U.S. domain, Fall 2002.

Seasonal Nitrate and Total Nitrate Performance

Table 3-4 provides the seasonal model performance statistics for nitrate
and total nitrate for the 12-km Eastern and Western domains.  Spatial
plots of the NMB and NME statistics (units of percent) for individual
monitors are also provided (Figures 3-61 – 3-92).  Overall, nitrate
and total nitrate performance is over-predicted in the EUS and
under-predicted in the WUS for all of the seasonal assessments except
the summer season, where nitrate is under-predicted in the EUS and WUS. 
In the East, nitrate and total nitrate is moderately over-predicted
during the winter season when nitrate is most abundant (NMB values
ranging from 26% to 50%).  In the West, during the winter, nitrate
performance is moderately under-predicted (NMB ~40%) and total nitrate
performance slightly under-predicted (NMB ~5%).  Nitrate and total
nitrate performance is mixed for the fall and spring seasons, with
moderate under-predictions occurring in the West and moderate
over-predictions occurring in the East. 

  

Table 3-4.  CMAQ 2002 seasonal model performance statistics for nitrate
and total nitrate.

CMAQ 2002 Nitrate 	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	Nitrate   (Winter)	STN	12-km EUS	1835	24.7	56.3	17.2	61.7



12-km WUS	600	-45.1	59.7	-54.0	81.5



Northeast	287	7.2	43.0	10.6	50.4



Midwest	575	50.3	62.2	44.4	58.1



Southeast	523	39.3	83.1	5.1	79.2



Central 	293	0.7	42.1	11.0	48.6



West	531	-48.2	59.3	-62.9	83.8

	IMPROVE	12-km EUS	2060	50.1	95.6	-15.1	102



12-km WUS	2371	-38.6	73.9	-97.1	127.2



Northeast	149	5.3	50.2	-16.0	75.8



Midwest	514	145.3	155.5	85.2	95.3



Southeast	447	33.7	90.7	-30.7	101.6



Central 	383	8.8	67.9	-14.6	89.9



West	2243	-42.2	76.5	-101.5	129.8

Total Nitrate  (Winter)	CASTNet	12-km EUS	710	25.8	34.8	28.0	35.5



12-km WUS	253	-5.3	39.9	10.8	43.8



Northeast	153	2.6	16.9	5.1	17.1



Midwest	184	51.8	52.6	45.6	46.1



Southeast	249	34.1	40.9	31.0	37.7



Central 	41	29.0	49.6	26.8	41.7



West	249	-3.2	41.2	11.3	44.1

Nitrate   (Spring)	STN	12-km EUS	2094	43.2	82.6	-3.7	78.8



12-km WUS	643	-30.6	59.9	-44.4	78.0



Northeast	362	56.0	88.6	24.4	68.0



Midwest	609	42.4	77.9	12.9	68.9



Southeast	624	36.3	107.4	-39.1	100.9



Central 	324	38.4	65.7	5.5	69.0



West	586	-32.0	59.2	-43.6	75.7

	IMPROVE	12-km EUS	1947	89.1	140.9	-24.5	106.1



12-km WUS	2409	-22.6	79.1	-79.7	113.4



Northeast	147	143.3	175.1	3.0	108.9



Midwest	512	149.0	175.6	35.0	96.6



Southeast	442	63.9	141.2	-66.1	130.8



Central 	307	54.8	113.0	-58.5	114.4



West	2347	-22.3	79.1	-79.3	113.0

Total Nitrate  (Spring)	CASTNet	12-km EUS	784	28.0	42.1	16.1	35.1



12-km WUS	289	-13.2	38.1	-6.2	39.3



Northeast	169	39.7	44.0	26.5	31.4



Midwest	203	42.5	47.6	31.4	37.4



Southeast	267	11.2	36.6	5.7	34.0



Central 	55	-3.1	38.0	-7.3	43.3



West	280	-12.4	39.6	-5.6	39.7

Nitrate   (Summer)	STN	12-km EUS	2392	-31.7	74.4	-85.7	110.4



12-km WUS	736	-61.1	69.0	-121.9	128.1



Northeast	414	-11.3	78.2	-42.9	91.2



Midwest	770	-27.1	71.4	-71.2	101.4



Southeast	697	-66.5	77.5	-126.2	133.9



Central 	325	-29.7	65.7	-62.9	89.3



West	660	-61.2	69.0	-122.3	128.6

	IMPROVE	12-km EUS	2203	-43.8	95.3	-125.9	143.9



12-km WUS	2631	-73.3	88.6	-155.4	161.7



Northeast	152	-28.4	87.6	-98.1	126



Midwest	526	-7.2	108.3	-98.1	128.8



Southeast	454	-41.6	107.5	-130.0	153.9



Central 	461	-68.6	82.7	-135.1	144.3



West	2467	-72.8	88.7	-155.8	162.1

Total Nitrate  (Summer)	CASTNet	12-km EUS	868	4.3	27.2	-4.8	30.5



12-km WUS	313	-36.3	46.3	-42.3	54.0



Northeast	176	9.3	23.3	4.6	21.8



Midwest	233	9.4	28.8	0.6	29.3



Southeast	298	3.5	29.6	-2.1	33.7



Central 	68	-18.4	27.2	-24.5	32.5



West	299	-37.6	47.6	-43.0	54.8

Nitrate        (Fall)	STN	12-km EUS	2449	13.9	59.9	-30.3	81.2



12-km WUS	747	-44.6	65.9	-56.1	87.9



Northeast	425	11.4	41.6	-3.7	55.0



Midwest	777	33.8	76.2	-10.5	77.1



Southeast	696	-8.8	73.1	-78.6	108.3



Central 	356	20.6	51.3	-5.5	67.6



West	669	-48.0	65.6	-61.0	89.1

	IMPROVE	12-km EUS	2304	53.1	100.5	-40.4	111.6



12-km WUS	2699	-16.0	84.3	-70.3	116.4



Northeast	149	42.8	66.9	-35.1	100.2



Midwest	517	112.7	151.1	-5.5	108.8



Southeast	460	43.3	121.7	-85.8	136.5



Central 	521	41.1	81.0	-26.6	104.9



West	2465	-29.3	82.7	-77.7	118.5

Total Nitrate  (Fall)	CASTNet	12-km EUS	809	41.0	46.3	30.9	39.8



12-km WUS	302	-12.2	49.6	-5.4	45.9



Northeast	164	35.9	37.1	29.0	30.1



Midwest	219	55.9	59.3	43.1	47.3



Southeast	271	42.3	51.3	31.4	43.7



Central 	65	23.0	31.8	17.1	30.5



West	289	-15.6	51.7	-6.7	46.9





Figure 3-61.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure 3-62.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure 3-63.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Winter 2002.

Figure 3-64.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Winter 2002.

Figure 3-65.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-66.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-67.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Spring 2002.

Figure 3-68.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Spring 2002.

Figure 3-69.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-70.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-71.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Summer 2002.

Figure 3-72.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Summer 2002.

Figure 3-73.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-74.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-75.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Fall 2002.

Figure 3-76.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Eastern U.S. domain, Fall 2002.

Figure 3-77.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-78.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-79.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Western U.S. domain, Winter 2002.

Figure 3-80.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Western U.S. domain, Winter 2002.

Figure 3-81.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-82.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-83.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Western U.S. domain, Spring 2002.

Figure 3-84.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Western U.S. domain, Spring 2002.

Figure 3-85.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-86.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-87.  Normalized Mean Bias (%) of total nitrate by monitor for
12-km Western U.S. domain, Summer 2002.

Figure 3-88.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Western U.S. domain, Summer 2002.

Figure 3-89.  Normalized Mean Bias (%) of nitrate by monitor for 12-km
Western U.S. domain, Fall 2002.

Figure 3-90.  Normalized Mean Error (%) of nitrate by monitor for 12-km
Western U.S. domain, Fall 2002.

Figure 3-91.  Normalized Mean Bias (%) of total nitrate by monitor for 
12-km Western U.S. domain, Fall 2002.

Figure 3-92.  Normalized Mean Error (%) of total nitrate by monitor for
12-km Western U.S. domain, Fall 2002.

Seasonal Ammonium Performance

Table 3-5 lists the performance statistics for ammonium PM at the STN
and CASTNet sites.  Figures 3-93 – 3-108 show spatial plots of the NMB
and NME statistics (units of percent) for individual monitors.  In the
winter, ammonium performance varies across the EUS and WUS, with STN and
CASTNet networks showing an over-prediction in the East (NMB values
range from 17% to 27) and an under-prediction in the West (NMB values
range from -27% to -11%).   Likewise, ammonium performance for the fall
and spring season in the East and West is similar to that of the winter
season.  However, in the summer, model predictions in the EUS are near
negligible at STN sites and under-predicted at CASTNet sites.  Ammonium
predictions in the summer are moderately under-predicted for the West in
both the rural and urban sites (NMB ~ 28%).  

Table 3-5.  CMAQ 2002 seasonal model performance statistics for
ammonium.

CMAQ 2002 Ammonium	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	Winter	STN	12-km EUS	2156	27.2	47.3	29.7	49.8



12-km WUS	633	-26.8	59.1	9.6	72.7



Northeast	287	10.6	35.6	18.8	41.1



Midwest	575	34.6	44.8	37.5	44.6



Southeast	523	29.3	52.3	20.8	48.7



Central 	614	31.9	57.0	35.9	58.7



West	531	-33.8	57.2	1.2	72.4

	CASTNet	12-km EUS	711	16.7	31.1	16.1	31.2



12-km WUS	253	-11.1	44.1	-7.5	43.0



Northeast	154	-0.1	19.3	3.2	20.8



Midwest	184	49.3	51.3	43.0	44.5



Southeast	249	12.7	29.4	9.3	27.5



Central 	41	20.6	41.3	13.7	40.7



West	249	-13.9	45.5	-8.0	43.1

Spring	STN	12-km EUS	2396	16.9	44.2	12.5	43.4



12-km WUS	667	-6.1	54.0	22.5	54.0



Northeast	362	34.6	57.6	26.7	47.2



Midwest	609	17.4	39.2	18.1	37.0



Southeast	624	11.4	38.6	9.3	40.4



Central 	626	9.5	45.7	1.0	50.5



West	586	-8.9	54.9	22.7	55.2

	CASTNet	12-km EUS	777	24.2	40.4	13.2	33.3



12-km WUS	287	-6.1	38.0	-3.1	33.3



Northeast	167	48.6	52.8	32.7	37.7



Midwest	201	29.7	38.5	22.0	31.3



Southeast	267	2.4	30.5	-0.7	31.3



Central 	55	3.2	41.5	-3.3	39.7



West	278	-9.8	37.0	-4.3	33.1

Summer	STN	12-km EUS	2768	1.0	35.0	6.1	43.8



12-km WUS	805	-29.1	48.3	-6.0	49.7



Northeast	414	13.9	36.4	21.2	43.1



Midwest	770	-4.1	33.2	12.4	42.7



Southeast	697	0.5	33.8	1.4	39.3



Central 	701	0.7	38.2	-2.8	50.0



West	660	-36.3	54.1	-8.6	54.0

	CASTNet	12-km EUS	868	-11.8	25.3	-17.4	31.3



12-km WUS	313	-26.0	40.6	-27.8	44.8



Northeast	176	5.5	20.3	5.2	20.6



Midwest	233	-17.2	25.5	-18.9	29.4



Southeast	298	-22.1	29.2	-31.2	39.9



Central 	68	-1.1	24.2	-5.9	30.4



West	299	-30.0	43.3	-29.6	45.6

Fall	STN	12-km EUS	2837	9.0	39.0	12.7	44.6



12-km WUS	821	-25.8	58.9	5.9	58.2



Northeast	425	8.2	32.5	20.4	40.0



Midwest	777	11.7	39.4	13.4	44.6



Southeast	696	-1.23	35.0	-3.7	40.2



Central U.S.	744	20.9	47.8	23.6	49.9



West	669	-35.5	59.0	-1.8	59.0

	CASTNet	12-km EUS	810	4.0	29.7	2.4	30.7



12-km WUS	303	-18.1	48.0	-11.6	43.3



Northeast	164	13.8	22.8	13.1	21.7



Midwest	219	7.3	34.1	9.3	32.2



Southeast	271	-9.2	31.6	-12.3	34.6



Central	65	14.9	34.1	10.9	34.4



West	290	-24.9	48.7	-13.7	43.5



Figure 3-93.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Eastern U.S. domain, Winter 2002.

Figure  3-94.  Normalized Mean Error (%) of ammonium by monitor for 
12-km Eastern U.S. domain, Winter 2002.

Figure 3-95.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-96.  Normalized Mean Error (%) of ammonium by monitor for 12-km
Eastern U.S. domain, Spring 2002.

Figure 3-97.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-98.  Normalized Mean Error (%) of ammonium by monitor for 12-km
Eastern U.S. domain, Summer 2002.

Figure 3-99.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Eastern U.S. domain, Fall 2002.

Figure 3-100.  Normalized Mean Error (%) of ammonium by monitor for
12-km Eastern U.S. domain, Fall 2002.

Figure 3-101.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Western U.S. domain, Winter 2002.

Figure 3-102.  Normalized Mean Error (%) of ammonium by monitor for
12-km Western U.S. domain, Winter 2002.

Figure 3-103.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Western U.S. domain, Spring 2002.

Figure 3-104.  Normalized Mean Error (%) of ammonium by monitor for
12-km Western U.S. domain, Spring 2002.

Figure 3-105.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Western U.S. domain, Summer 2002.

Figure 3-106.  Normalized Mean Error (%) of ammonium by monitor for
12-km Western U.S. domain, Summer 2002.

Figure 3-107.  Normalized Mean Bias (%) of ammonium by monitor for 12-km
Western U.S. domain, Fall 2002.

Figure 3-108.  Normalized Mean Error (%) of ammonium by monitor for
12-km Western U.S. domain, Fall 2002.

Seasonal Elemental Carbon Performance

Table 3-6 presents the seasonal performance statistics of elemental
carbon for the urban and rural 2002 monitoring data.  Likewise, NMB and
NME spatial plots (units of percent) for individual monitors are also
provided in Figures 3-109 – 3-124.  In the winter, elemental carbon
performance is mixed across the STN and IMPROVE networks, with a slight
over-prediction in the East (NMB=10%) and slight under-prediction in the
West (NMB= -7%) for IMPROVE and a moderate over-prediction in the East
(NMB=64%) and in the West (NMB= -36%).  Nationally, elemental carbon
predictions are moderately over-predicted for the fall, spring and
summer seasons for STN, however, elemental carbon is generally
under-predicted for the East and West at IMPROVE.  These biases and
errors are not unexpected since there are known uncertainties among the
scientific community in carbonaceous emissions/measurements, transport,
and deposition processes.

Table 3-6.  CMAQ 2002 seasonal model performance statistics for
elemental carbon.

CMAQ 2002 Elemental Carbon	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	Winter	STN	12-km EUS	2136	64.3	93.4	38.7	63.2



12-km WUS	629	35.8	83.8	13.6	63.7



Northeast	297	72.9	87.9	50.2	61.1



Midwest	574	89.3	98.3	54.7	63.7



Southeast	524	23.7	65.1	16.0	50.6



Central 	585	99.2	132.9	49.9	74.7



West	529	43.6	85.4	12.4	63.1

	IMPROVE	12-km EUS	2033	10.4	53.4	-0.6	51.4



12-km WUS	2429	-7.4	70.5	-33.7	68.7



Northeast	149	-0.8	31.8	6.0	32.8



Midwest	512	56.2	70.2	40.8	53.6



Southeast	439	-18.7	41.4	-23.2	47.1



Central 	368	-8.6	49.9	-8.6	50.7



West	2303	-10.1	70.5	-36.6	69.5

Spring	STN	12-km EUS	2360	42.2	78.8	16.1	56.2



12-km WUS	687	57.3	95.4	15.6	64.0



Northeast	364	23.2	56.7	7.6	47.8



Midwest	618	46.8	75.1	21.0	53.9



Southeast	600	13.4	63.5	1.7	49.6



Central 	603	96.7	122.4	37.5	68.2



West	588	64.2	101.2	15.9	66.0

	IMPROVE	12-km EUS	1920	-13.4	44.4	-20.1	46.2



12-km WUS	2369	-2.6	62.4	-16.6	51.6



Northeast	147	-22.4	34.3	-29.2	42.6



Midwest	510	19.3	51.5	4.2	45.5



Southeast	443	-30.1	43.0	-36.5	49.6



Central 	293	-37.7	42.5	-47.4	55.6



West	2307	-1.1	63.0	-16.0	51.5

Summer	STN	12-km EUS	2725	38.9	71.88	18.8	54.2



12-km WUS	834	54.8	82.7	24.6	58.0



Northeast	412	29.9	48.8	22.3	43.1



Midwest	771	35.8	62.0	21.4	48.3



Southeast	688	14.4	69.0	5.4	53.4



Central 	666	97.7	119.2	37.9	67.9



West	686	63.1	89.6	25.0	60.5

	IMPROVE	12-km EUS	2127	-40.0	52.2	-49.5	62.6



12-km WUS	2590	-22.8	65.5	-29.5	60.1



Northeast	153	-44.7	46.8	-65.3	68.5



Midwest	523	-31.1	53.8	-38.8	57.5



Southeast	456	-49.9	52.7	-62.9	69.0



Central 	409	-44.6	50.8	-53.6	67.4



West	2430	-22.7	66.8	-29.9	60.8

Fall	STN	12-km EUS	2810	35.2	72.3	17.7	55.4



12-km WUS	825	35.0	75.2	17.4	60.7



Northeast	425	29.7	50.4	23.1	44.7



Midwest	781	40.2	71.5	14.4	55.0



Southeast	694	15.4	66.4	70.0	52.6



Central 	716	76.8	100.4	39.3	62.7



West	672	37.1	77.2	13.9	61.5

	IMPROVE	12-km EUS	2202	-13.4	45.1	-22.0	50.5



12-km WUS	2681	-15.1	69.7	-36.9	67.3



Northeast	150	-13.9	33.1	-20.0	41.4



Midwest	511	7.4	51.7	-3.5	46.3



Southeast	457	-32.9	41.6	-44.4	56.1



Central 	462	-7.8	46.32	-14.4	50.0



West	2453	-19.3	70.1	-42.1	68.8



Figure 3-109.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Winter 2002.

Figure 3-110.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Winter 2002.

Figure 3-111.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Spring 2002.

Figure 3-112.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Spring 2002.

Figure 3-113.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Summer 2002.

Figure 3-114.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Summer 2002.

Figure 3-115.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Fall 2002.

Figure 3-116.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Fall 2002.

Figure 3-117.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Eastern U.S. domain, Winter 2002.

Figure 3-118.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Winter 2002.

Figure 3-119.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Spring 2002.

Figure 3-120.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Spring 2002.

Figure 3-121.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Summer 2002.

Figure 3-122.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Summer 2002.

Figure 3-123.  Normalized Mean Bias (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Fall 2002.

Figure 3-124.  Normalized Mean Error (%) of elemental carbon by monitor
for 12-km Western U.S. domain, Fall 2002.

Seasonal Organic Carbon Performance

Seasonal organic carbon performance statistics are provided in Table
3-7.  Spatial plots of NMB and NME (units of percent) for individual
monitors are also provided in Figures 3-125 – 3-140.  The model
predictions generally show moderate under-predictions for all Eastern
sites located in the urban STN sites (NMB values range from -12% to
-67%) and rural IMPROVE sites (NMB values range from -3% to -50%).  
Organic carbon performance in the EUS and WUS shows the largest under
estimations during the summer season.  For IMPROVE, organic carbon
performance shows a negative bias in the West (NMB= -3%) and a positive
bias in the East (NMB=24%).  For STN, organic carbon is under-predicted
in the East (NMB= -12%) and West (NMB= -26%).  These biases and errors
reflect sampling artifacts among each monitoring network.  In addition,
uncertainties exist for primary organic mass emissions and secondary
organic aerosol formation.  Research efforts are ongoing to improve fire
emission estimates and understand the formation of semi-volatile
compounds, and the partitioning of SOA between the gas and particulate
phases.

Table 3-7.  CMAQ 2002 seasonal model performance statistics for organic
carbon.

CMAQ 2002 Organic Carbon	No. of Obs.	NMB (%)	NME (%)	FB (%)	FE (%)







	Winter	STN	12-km EUS	2063	-12.4	51.2	-2.5	55.2



12-km WUS	606	-25.6	62.0	-22.4	62.6



Northeast	284	-18.1	58.7	-0.7	62.7



Midwest	552	24.4	61.6	34.0	60.4



Southeast	520	-32.4	44.0	-27.8	51.5



Central 	568	-22.9	45.4	-13.2	48.5



West	507	-24.2	63.0	-22.0	64.3

	IMPROVE	12-km EUS	2032	24.5	65.4	14.1	55.4



12-km WUS	2432	-2.9	59.9	-4.3	58.9



Northeast	149	4.6	43.1	16.6	45.0



Midwest	512	89.2	104.2	63.5	71.9



Southeast	439	-12.9	42.9	-22.1	49.9



Central 	366	-5.1	52.9	-4.5	51.4



West	2307	-4.8	59.3	-5.1	59.4

Spring	STN	12-km EUS	2241	-19.1	53.6	-15.7	60.8



12-km WUS	656	-19.8	63.4	-13.7	64.5



Northeast	337	-19.9	57.1	-6.6	63.8



Midwest	583	8.5	55.3	9.8	55.8



Southeast	590	-25.9	47.5	-22.7	54.0



Central 	579	-38.7	53.2	-45.7	68.3



West	560	-15.9	65.9	-7.1	65.5

	IMPROVE	12-km EUS	1917	-27.2	53.0	-32.0	58.5



12-km WUS	2369	-23.7	54.5	-26.4	56.3



Northeast	147	-29.7	43.9	-28.6	52.1



Midwest	508	15.6	46.4	8.5	45.0



Southeast	442	-42.8	58.3	-60.6	73.0



Central 	293	-53.9	59.6	-71.6	81.0



West	2307	-21.5	53.6	-24.4	55.1

Summer	STN	12-km EUS	2690	-67.5	69.4	-95.0	100.3



12-km WUS	832	-55.4	60.0	-76.2	83.6



Northeast	408	-69.2	69.8	-98.4	101.2



Midwest	754	-68.1	71.5	-88.4	97.7



Southeast	683	-68.7	69.5	-100.9	104.5



Central	659	-63.3	64.9	-91.1	95.7



West	684	-54.0	59.3	-73.3	81.8

	IMPROVE	12-km EUS	2133	-66.7	69.0	-95.5	99.0



12-km WUS	2595	-50.4	63.7	-61.9	76.0



Northeast	153	-70.4	70.7	-103.1	104.0



Midwest	523	-66.2	68.5	-73.8	80.0



Southeast	460	-73.8	74.8	-122.3	123.2



Central 	411	-74.2	74.5	-120.0	120.7



West 	2435	-49.4	63.2	-58.1	73.0

Fall	STN	12-km EUS	2732	-37.6	50.2	-37.8	60.6



12-km WUS	809	-40.4	57.9	-38.7	63.4



Northeast	418	-44.1	51.3	-42.0	60.1



Midwest	752	-14.6	45.4	-13.2	51.9



Southeast	681	-47.6	52.3	-53.1	65.9



Central 	698	-43.7	50.7	-49.2	63.5



West	657	-41.0	59.9	-39.6	66.8

	IMPROVE	12-km EUS	2205	-25.5	47.2	-32.4	57.6



12-km WUS	2686	-29.4	56.5	-30.0	59.9



Northeast	149	-41.0	44.6	-44.0	53.0



Midwest	514	4.1	43.9	0.5	45.9



Southeast	459	-43.6	50.8	-71.3	77.4



Central 	461	-37.8	51.8	-47.2	64.6



West	2459	-29.9	56.4	-29.5	59.5



Figure 3-125.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Eastern U.S. domain, Winter 2002.

Figure 3-126.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Eastern U.S. domain, Winter 2002.

Figure 3-127.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Eastern U.S. domain, Spring 2002.

Figure 3-128.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Eastern U.S. domain, Spring 2002.

Figure 3-129.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Eastern U.S. domain, Summer 2002.

Figure 3-130.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Eastern U.S. domain, Summer 2002.

Figure 3-131.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Eastern U.S. domain, Fall 2002.

Figure 3-132.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Eastern U.S. domain, Fall 2002.

Figure 3-133.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Western U.S. domain, Winter 2002.

Figure 3-134.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Western U.S. domain, Winter 2002.

Figure 3-135.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Western U.S. domain, Spring 2002.

Figure 3-136.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Western U.S. domain, Spring 2002.

Figure 3-137.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Western U.S. domain, Summer 2002.

Figure 3-138.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Western U.S. domain, Summer 2002.

Figure 3-139.  Normalized Mean Bias (%) of organic carbon by monitor for
12-km Western U.S. domain, Fall 2002.

Figure 3-140.  Normalized Mean Error (%) of organic carbon by monitor
for 12-km Western U.S. domain, Fall 2002.

See EPA/OAQPS Air Quality Modeling Platform for the Ozone National
Ambient Air Quality Standard Final Rule Regulatory Impact Analysis
(Figure II-1) for the map of the CMAQ modeling domain.

 The subregions are defined by States where: Midwest is IL, IN, MI, OH,
and WI; Northeast is CT, DE,

MA, MD, ME, NH, NJ, NY, PA, RI, and VT; Southeast is AL, FL, GA, KY, MS,
NC, SC, TN, VA, and

WV; Central is AR, IA, KS, LA, MN, MO, NE, OK, and TX; West is AK, CA,
OR, WA, AZ, NM, CO, UT, WY, SD, ND, MT, ID, and NV.

 Gilliam, R. C., W. Appel, and S. Phillips. The Atmospheric Model
Evaluation Tool (AMET): Meteorology Module. Presented at 4th Annual CMAS
Models-3 Users Conference, Chapel Hill, NC, September 26 - 28, 2005.

 See: U.S. Environmental Protection Agency; Technical Support Document
for the Final Clean Air Interstate Rule: Air Quality Modeling; Office of
Air Quality Planning and Standards; RTP, NC; March 2005 (CAIR Docket
OAR-2005-0053-2149); and U.S. Environmental Protection Agency, 2006.
Technical Support Document for the Final PM NAAQS Rule: Office of Air
Quality Planning and Standards, Research Triangle Park, NC 

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