Changes in MATS version 2.2.1 (compared to version 1.5.1)  4/21/09


Annual PM2.5

1) Added capability to perform the annual PM2.5 attainment test (calculating future year PM2.5 concentrations) by applying the 
EPA photochemical modeling guidance procedures.  See:  http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf

2) Annual average PM2.5 MATS also allows the creation of gridded Pm2.5 spatial fields, both with and without data fusion 
(combining ambient data and model output).

3) The annual PM2.5 attainment test calculations and GUI details are included in the revised MATS user's guide.  The user's guide
can be accessed from within MATS and is also included as a separate PDF file in the installer package. 

4) MATS includes updated ambient datasets.  For PM2.5, "official" daily average PM2.5 data is included for the 1999-2007 period.  This
is data that can be used to calculate official PM2.5 design values.  MATS also includes PM2.5 species data from the STN and IMPROVE
monitoring networks for the 2002-2006 period.  This data is used to calculate species fractions at FRM monitoring sites (point estimates)
and PM2.5 concentrations and species fractions for all grid cells (for spatial fields).


Ozone 

1) Ozone design value data has been updated to include design values through the 2005-2007 period (data file includes data from 1997-1999
to 2005-2007)

2) Two additional options have been added to the ozone "RRF and Spatial Gradient" GUI page:
a) A subrange of days can be specified so that only part of the model output data file is used.  For example, if a MATS 
input file contains photochemical model output for the May-September time period, a subrange of days can be specified so 
that MATS only uses data from June-August.

b) There is an option to "pair days based on high concentration instead of date".  The default option is to pair days between the base
and future year model files matched by date.  This option allows the RRFs to be calculated based on the number of days above the specified
threshold in the base year.  For example, if there are 12 high concentration days which meet the specified threshold used in the RRF 
calculation, then MATS will calculate RRFs based on the highest 12 future year model days at that location.  This can be useful 
for applications where the base and future year meteorology is not the same (such as climate modeling).


Visibility 

1) The default ambient visibility dataset for the "new IMPROVE equation" has been updated with 2005 and 2006 data.  The dataset
now covers the period from 2000-2006.