Not logged in - Login
< back

3SAQS/WAQS Monitoring Network Assessments

This Wiki page contains materials for Monitoring Network Assessments conducted by the 3SAQS and WAQS. The 2014 3SAQS Assessment evaluated the status of ambient air quality monitoring in Colorado, Wyoming and Utah. The 2017 WAQS study expanded the geographical region of the Three State Study to seven states by adding New Mexico, Montana, North Dakota and South Dakota. Final reports, supplemental materials, and meeting archives for the 3SAQS and WAQS Assessments are available below.

3SAQS 2014

3SAQS Monitoring Network Assessment Technical Memo (9 June, 2014)
3SAQS Network Recommendations (27 Feb., 2014)
Document Archive
Cost Survey

WAQS 2017


WAQS Monitoring Network Assessment Final Report (3 Nov., 2017)


WAQS Monitoring Network Assessment Working Group Meetings
WAQS Governing Board 2017.05.05.pptx (5 May, 2017)
WAQS OC 2017.11.06.pptx (6 Nov., 2017)

Monitoring Sites

Tabular Data

Monitors An Excel Workbook that lists monitors in the WAQS region. The Workbook has a worksheet for all monitors in the WAQS region, and separate worksheets listing monitors by organization. Information in the workbook was obtained from the AQS Monitor Listing 1 and the IWDW 2.

Note: The map image files can be viewed at full resolution in most web browsers by clicking on, and hence zooming to, a specific region of the map.

Maps by Parameter Maps showing monitors for the parameters (pollutants) considered in the WAQS MNA.

All monitors non-overlapping labels
All monitors labels at monitor locations. Some lables are obscured.
O3 and Precursors O3, NO2 and VOCs (ethane and formaldehyde shown in red, or red cross hatching)
PM2.5 FRM/FEM and non-FRM/FEM PM2.5 monitors
PM2.5 with supplemental monitoring monitors reporting PM2.5 Raw and PM2.5 Total
Ions and Ammonia PM2.5 sulfate and nitrate ions and NH3
Meteorology wind speed and temperature
NADP sites AMoN and NTN

Maps by Organization Maps showing monitors affiliated with state agencies and/or organizations considered in the WAQS MNA process.
New Mexico-ED, Albuquerque DEQ
Other Monitors not associated with groups listed above. Generally industry sponsored monitoring.

Current Conditions

O3 MD8s 4th Highest Maximum Daily 8-hour average (MD8) for 2010-2015. MD8s were calculated 8-hour average data from AQS 3. 2016 MD8s are not included because data used for this portion of the WAQS Assessment did not include finalized 2016 data.
2010 2011 2012 2013 2014 2015

Design Values County level design values (DVs) from the EPA OEI Map Service4.

2013-2015 County level DVs overlaid with site level 2015 O3 MD8s.
O3 MD8
O3 MD8 detail Counties with monitor(s) reporting > 70ppb

2014-2016 County Level DVs overlaid with O3 monitor locations.
O3 MD8
O3 MD8 detail Counties with monitor(s) reporting > 70ppb
NO2 1-hour
NO2 annual
PM2.5 24-hour
PM2.5 24-hour w/ CIAs Overlaid with Class I areas
PM2.5 annual
PM2.5 24-hour NAAs WAQS Region
PM2.5 24-hour NAAs detail Wasatch Front, overlaid with monitor locations

Monitor-to-Monitor Analysis


Locations of highly correlated monitors, as defined in the MNA Report.6

Locations of the top 10 most highly correlated for O3, NO2 and PM2.5
Top 10
Top 10 detail detail of the Denver Metro Area

Tabular data

Excel spreadsheet with summary data from the monitor-to-monitor correlation analysis.
Monitor Correlations

Plot Archive

Scatter and time series plots for the monitor-to-monitor analysis.

Archive O3 MD8s and daily average O3, NO2 and PM2.5

Correlograms of the monitor-to-monitor correlation coefficient (R) vs distance between monitor pairs are used to estimate monitor spatial extents.

Archive Correlograms for daily average O3, NO2 and PM2.5

Representative Area Analysis

Air Basins
WAQS Air Basins 61 air basins defined in the WAQS MNA

Monitor Representative Area Representative areas are the monitor spatial extents clipped by air basin boundaries. Note that representative areas for PM2.5 FRM/FEM and PM2.5 non-FRM/FEM monitors were determined separately, although the results are combined on the maps in this section.

PM2.5 Includes Class I area overlays.

Gap Analysis Maps of active monitor location overlaid with active O&G wells. Other spatial layers are included for context. This analysis informed the recommendations of the WAQS MNA recommendations by highlighting underserved area in the current monitoring network.

O3 NO2 O3&NO2 PM2.5

O3 NO2 O3&NO2 PM2.5

O3 NO2 O3&NO2 PM2.5

New Mexico
O3 NO2 O3&NO2 PM2.5

O3 NO2 O3&NO2 PM2.5

North and South Dakota
O3 NO2 O3&NO2 PM2.5

Emissions Analysis
Emissions are from the WAQS 2011b modeling platform and incorporate WAQS 2011b_v2 O&G sector emissions

VOCs Emissions Wells Monitor Rankings
NMHC Emissions Wells Monitor Rnkings
NOx Emissions Wells Monitor Rankings
FP Emissions Wells Monitor Rankings

Additional Resources

Reports by State and Local Agencies

Colorado - CDPHE 2015 MNA 2017 Network Plan

Wyoming - WDEQ 2015 MNA 2016 Network Plan

Utah - UDEQ 2015 MNA 2016 Network Plan

New Mexico - NMED 2015 MNA 2017 Network Review Albuquerque 2017 Network Plan

SDDEP 2015 MNA 2017 Network Plan

NDDEQ 2017 Network Plan

MTDEQ 2016 Network Plan

GIS Data

O&G Well Locations
Colorado - COGCC GIS downloads see Well Surface Location Data
Layers: Wells.shp, Permist.shp, Permits_pending.shp; Filters: Facil_stat = Producing; Downloaded 2017-4-11

Montana & Dakotas - USGS Energy Developmet - GIS Data
Layer: PetroleumWells_041113; Filters: Producing (MD, ND, SD), not DRY (ND); Published: 2013-11-19; Downloaded 2016-10-24

New Mexico - NMOCD
Layer: NM_Wells_State_Wide_UTM_NAD_83_Z13; Filters: Status=Active, Well Type = Gas, Oil, Injection, Gas Storage; Downloaded 2016-10-25

Utah - DOGM GIS Data ftp
Layers: DNROilGasWells; Filters: Status = Producing, Active, Well Type = Oil well, Gas well, Gas injection, Gas storage; Downloaded 2017-4-11

Wyoming - WDEQ (Cara Keslar, personal communication)
Layers: wogcc_wells; Filters: WellStatus = Permit to Drill, Producing Gas Well, Producing Oil Well; Received 2017-4-7

2017 WAQS MNA GIS Data
Arc GIS mdx files, scripts and geodatabases used for the 2017 WAQS MNA
Design Values
Correlation Analysis
Gap Analysis
Emissions Analysis


1. EPA 2017a, AQS Pre-generated data files, 2017-05-26 update,,

2. IWDW 2017. Intermountain West Data Warehouse,

3. EPA 2017a, 2016-12-23 update.

4. EPA 2017b, Map Service: USEPA Office of Environmental Information (OEI). Data: U.S. EPA Office of Air and Radiation (OAR) - Office of Air Quality,, downloaded on Oct. 11, 2017.

4. 2014-2016 Design Value maps are overlaid with active monitoring locations, rather than site level MD8s, because data for 2016 O3 MD8s were not available at the time of this analysis.

5. EPA 2017b.

6. Highly correlated monitors are defined being correlated with another monitor with a regression coefficient (R2) >0.8 and average concentration within 10%. The average concentration criteria was set to 15% for NO2. Regressions use all available matching (that is, days where both monitor report data) 24-hour average data.