CMAQ 4.5 and 4.4 Comparison

• August 6 – 16, 2002 episode• 217 ozone monitoring sites in OTR• The response from the CAIR 2010 control

plus 50% VOC reduction within OTR• PM comparison - TEOM hourly PM 2.5 measurements - STN speciated data

Scatter plot

Statistics: 8-Hour Daily Max Ozone

CMAQ V4.4 CMAQ v4.5

Mean Bias -11.93 -8.19

Mean Absolute Gross Error

16.11 13.40

RMSE 19.65 16.84

Mean Normalized Bias

-13.16% -7.51%

R 0.71 0.74

Ratio of CAIR 2010+50VOCOTR Control to 2002 Base (above 60 ppb)

Daily Averaged PM2.5

Diurnal Variation PM2.5

STN PM2.5

STN SO4

STN NO3

STN NH4

EC at STN

OC at STN

Summary• CMAQ 4.5 predicted higher 8-hour ozone

concentration than CMAQ 4.4.• CMAQ 4.5 response to emission reduction

more sensitive than CMAQ 4.4 in this August 2002 episode.

• CMAQ 4.5 predicted lower PM2.5 concentration than CMAQ 4.4.