Appendix E 

Air Quality and Meteorological 

Preparations and Results 
1. Air Quality Data for 2002 

As part of the VISTAS Phase I modeling study, the VISTAS emissions and air quality modeling 

team of ENVIRON International Corporation, Alpine Geophysics (AG) and the University of 

California at Riverside (UCR) compiled ambient monitoring data for both gas and particulate 

species to be used in the VISTAS regional haze model performance evaluation. UCR took the 

lead in this activity. The contractor’s report (found in Appendix E.1) describes the sources of the 

ambient data and the steps taken in the processing and quality assurance (QA) of the data. In 

addition, the ambient data is being processed and formatted in preparation for use in software 

packages designed for the model performance evaluation. 

The goal was to preprocess the ambient data and present plots of ambient data on the project 

website so model performance evaluations when the model simulations were completed. The 

ambient data are available from the following 9 monitoring networks or databases: 

• EPA’s AQS (Environmental Protection Agency’s Air Quality System) database 

• PAMS (Photochemical Assessment Monitoring Stations) 

• IMPROVE (The Interagency Monitoring of Protected Visual Environments) 

• SEARCH (Southeastern Aerosol Research and Characterization) 

• EPA’s STN (Speciation Trends Network) 

• NADP (National Atmospheric Deposition Program) 

• CASTNET (Clean Air Status and Trend Network) 

• PM Supersites 

• NARSTO SOS99 Aircraft data (for the July 1999 episode only) 

• TVA measurement network 

• Georgia Institute of Technology Assessment of Spatial Aerosol Composition in 

Atlanta (ASACA) monitors. 

Note that there is some overlap in the above monitoring networks. For example, some data from 

PAMS (such as ozone and nitrogen oxides) are included in the AQS database, and it appears that 

the STN network may also include speciated particulate matter data from IMPROVE and other 

monitoring networks. Appendix E.1 contains maps of many of the existing and planned (as of 

January 2002) urban and rural fine particulate matter speciation networks. The available data 

from the above monitoring networks for the three episodes of VISTAS regional haze modeling 

(July 9-22, 1999, July 7-28, 2001 and January 1- 21, 2002) was obtained. The attempt was made 

to reconcile data from the various networks and to perform a high level QA of the ambient data. 

The monitoring networks, the available data, and QA efforts are described in their entirety in the 

previously mentioned VISTAS report. 

Additional data used in the air quality modeling include the Total Ozone Mapping Spectrometer 

(TOMS). TOMS data is available for 24-hour average and is obtained from 

http://toms.gsfc.nasa.gov/eptoms/ep.html. The TOMS data is used in the CMAQ radiation 

model (JPROC) to calculate photolysis rates.

AQ & Met – Preparations & Results Appendix E - 2 

Pre-Hearing Draft January 18, 2008 

Regional Haze SIP for TN Class I Areas 
1.1 Quality Assurance -- Overview 

The VISTAS Phase II emissions and air quality modeling team received emissions, 

meteorological and air quality data from other VISTAS contractors or other sources. As a first 

line of QA, a Gatekeeper function was defined to assure the data have been received correctly, 

evaluate the quality of the data, and document the data received. Separate air quality, 

meteorological and emissions Gatekeepers have been identified whose roles are defined below. 

In addition, a Data Management Gatekeeper has been defined who will post data, reports and 

results to the project website and archive all key data generated in the project. 

• Air Quality Data Gatekeeper. Obtain air quality data as appropriate for model input 

development and model performance evaluation and assure quality of all air quality 

data obtained, consistent with approved QA plan. This gatekeeper will also provide 

documentation of evaluation and generate IC/BC inputs for CMAQ for all modeling 

runs. 

• Meteorological Gatekeeper. Obtain meteorological data, as MM5 or MCIP files, as 

appropriate for annual 2002 modeling runs and other episode periods and perform 

data quality checks as approved in QA plan together with appropriate documentation 

of model performance evaluation activities.

1.2 Quality Assurance of Air Quality Data 

In gathering data from the monitoring networks it is assumed that the agency or researcher 

responsible for collecting the data performed quality assurance on the data. However, it is 

possible that the data sets may contain erroneous data (i.e., missing data, zeros during 

calibration, unrealistic values, etc). Due to poor documentation or poor formatting of some data 

sets it is also possible that mistakes may be made in our processing of the data. To guard against 

this possibility, a plan to perform a high level QA by visually inspecting time-series plots and 

scatter plots of the ambient data was developed and is outlined as follows: 

Plots of Time Series

Time series plots are generated for PAMS species. The plots should be inspected for the 

following: 

• Large "jumps" or "dips" in the concentrations 

• Periodicity of peaks, calibration carryover 

• Unexpected diurnal behavior (i.e., isoprene) 

• Unexpected relationships among species 

• High single-hour concentrations of less abundant species 

AQ & Met – Preparations & Results Appendix E - 3 

Pre-Hearing Draft January 18, 2008 

Regional Haze SIP for TN Class I Areas 
Scatter Plots

Scatter plots may be prepared for the following: 

• Total NMOC vs. species group totals, vs. individual species 

• Benzene vs. Toluene, Acetylene, Ethane 

• Scatter plots comparing data for a single species measured with different sampling 

methods 

• Plots of reconstructed mass versus measured mass (to reveals if anything unusual is 

happening with the chemical measurements) 

• Plots of molal particulate ammonium versus the molal sum of sulfate and particulate 

nitrate (as a sanity check on the ion balance in the PM chemical measurements) 

If data is identified that appears flawed it will be flagged and either corrected if the error is in the 

processing step, or removed from the data set.

IMPROVE site Quality Assurance

The IMPROVE data have passed the “Level 0 and Level 1” quality assurance and control 

procedure conducted by the Crocker Nuclear Laboratory at UC Davis. In addition, the data are 

added to the online database after a 30 day period to allow the States, Tribes, Federal Land 

Managers’ or any other organization a chance to review and comment on the accuracy, 

credibility, and/or representativeness of aerosol speciation data collected and the reconciliation 

of any issues these organizations may find. In the past, additional QA was not performed on the 

IMPROVE data, but simply used the data obtained from the Cooperative Institute for Research 

in Atmosphere (CIRA) website: http://vista.cira.colostate.edu/improve.

Further detail on the quality assurance of air quality data modeling data can be found in the 

VISTAS document in Appendix E.1. Additional information on quality assurance procedures 

can be found in the QAPP, as referenced in Appendix C of the Regional Haze State 

Implementation Plan for the North Carolina Class I Areas. 

2. Meteorological Data for 2002 

The observations used for performance statistics come primarily from UCAR’s ds472.0 (TDL) 

archive (http://dss.ucar.edu/datasets/ds472.0/). These data are quality controlled and converted 

to NetCDF format, thus allowing the data to be visualized on the model fields via a graphical 

visualization tool such as PAVE. Unfortunately, the precipitation values in this dataset are not 

reliable, so precipitation statistics were calculated based on the 24-hour gridded accumulations 

available online from the Climate Prediction Center (CPC) (http://www.cpc.ncep.noaa.gov). 

These fields, originally at 0.25- degree resolution, undergo grid transformation to match the 

VISTAS 36-km and 12-km domains. Since the CPC analyses are derived primarily from rain 

gauges, the statistics are only calculated over cells that MM5 deems to be land. 

AQ & Met – Preparations & Results Appendix E - 4 

Pre-Hearing Draft January 18, 2008 

Regional Haze SIP for TN Class I Areas 
For aloft analyses standard sounding observations from the NCEP ds353.4 archive 

(http://dss.ucar.edu/datasets/ds353.4/) were processed. These observations are quality controlled 

and used to produce model/observation skewT sounding plots for selected sites. Additionally, 

the observations were integrated into sigma levels that match the MM5 specifications, after 

which the performance can be statistically analyzed at sigma levels 9, 17, and 22 (~500m, 

~1600m, ~3400m, respectively). Qualitative profiler plots showing model/observed hourly 

winds are also created based upon the data stored at the Forecast Systems Lab 

(http://www.profiler.noaa.gov/jsp). For additional evaluation details and results, please refer to 

the Protocol for Annual MM5 Modeling in Support of VISTAS (DRAFT) Task 3a Deliverable 

found in Appendix E.2. 

AQ & Met – Preparations & Results Appendix E - 5 

Pre-Hearing Draft January 18, 2008 

Regional Haze SIP for TN Class I Areas 
Appendix E.1 

Review and Assessment of Available Ambient 

Air Quality Data to Support Modeling and 

Modeling Performance Evaluation for the 

Three VISTAS Phase I Episodes 
Appendix E.2 

Protocol for Annual MM5 Modeling 

in Support of VISTAS