# Presentation: 781431

## Implementing the National Ambient Air Monitoring Strategy

- Presented at the
- 2005 National Air Quality Conference
- Kevin A. Cavender
- EPA/OAQPS/EMAD
- February 14, 2005

***Network Design Issues***

## Agenda

- Network design recommendations in National Ambient Air Monitoring Strategy (NAAMS)
- Two tools to use in identifying high and low value monitoring sites
- Simplified example

## Network Design Recommendations in NAAMS

- New multi-pollutant monitoring network
- NCore Level 2
- 70-100 sites
- 2/3 urban sites
- 1/3 rural sites

## Draft NCore Level 2 Recommendations

***First Draft NCore Level 2 Recommendations****

- *Sites recommended by States with initial screening by EPA.

## Network Design Recommendations in NAAMS

- Reductions in existing monitoring
- Major reductions in PM10, NO2, SO2, and Pb compliance monitoring
- Minor reductions in ozone and PM2.5 compliance monitoring
- Significant reductions in PM2.5 speciation monitoring
- Significant reductions in Photochemical Assessment Monitoring sites (PAMS)

## Network Design Recommendations in NAAMS

- Frequent network assessments
- Annually at State/Local level
- Every 5 years at Regional level
- Intended to:
- Identify new data needs and associated technologies
- Increase network coverage
- Reduce network redundancy
- Preserve important trends sites
- Minimize network costs

## Two Tools to Aid In Net Design

- Decision Matrix
- ArcGIS software

## What is a Decision Matrix?

- A decision matrix is a an approach that can be used to rank alternatives (in this case site locations)
- Steps involved
- Identify and weight criteria that add value to a site
- Score each site for each criteria
- Rank each site based on the total score for all criteria

## Example Decision Matrix

| Cars | MPG
Weight: 50% |  | # of Doors
Weight: 30% |  | Style
Weight: 20% |  | Total |
| --- | --- | --- | --- | --- | --- | --- | --- |
|  | Value | Score | Value | Score | Value | Score |  |
| Economy
 | 26/35 | 1
(0.5)* | 4 | 1
(0.3) | Low | 0
(0) | 0.8 |
| Sports | 20/29 | 0.6
(0.3) | 2 | 0
(0) | High | 1
(0.2) | 0.5 |
| SUV | 15/19 | 0
(0) | 4 | 1
(0.3) | Med. | 0.5
(0.1) | 0.4 |

- * Bracketed scores include weighting.

## What Criteria Add Value to a Site?

- Spatial coverage
- Distance to next nearest site
- Area represented
- Uncertainty in concentration
- Error in estimating
- Lack of redundant monitors
- Scale of representativeness
- Elevated concentrations
- Population near site
- Value in attainment decisions
- Design value sites
- % of NAAQS
- Costs of operation
- Track record
*Others...*

## Methods to Score Criteria

- Proportionately
- e.g., (Value-Min)/(Max-Min)
- Binning
- e.g.,  (>NAAQS=1, >%80 NAAQS=0.5, <80% NAAQS=0)
- All or nothing
- Protected
- Design value sites
- Others...

## Distance to Nearest Site

- Distances between sites can be estimated based on their latitudes and longitudes using the following formula:
- D = 1.852 * 60 * ARCOS ( SIN(L1) * SIN(L2) + COS(L1) * COS(L2) * COS(DG))
- Where:
- L1 = latitude at the first point (degrees)
- L2 = latitude at the second point (degrees)
- G1 = longitude at the first point (degrees)
- G2 = longitude at the second point (degrees)
- DG = longitude of the second point minus longitude of the first point (degrees)
- DL = latitude of the second point minus latitude of the first point (degrees)
- D = computed distance (km)
- Note: If your calculator returns the ARCOS result as radians you will have to convert the radians to degrees before multiplying by 60 and 1.852 degrees = (radians/PI)*180

## Area Represented

- A series of “Theisian polygons” created so that every location within a polygon is closer to the site in that polygon than any other site.  The area of the polygon can be used as a measure of the area represented by that site.

## Error in Estimating

- “Jacknife” technique relying on spatial averaging (e.g. Kriging)
- Provides estimate of error in spatial averaging techniques for site if that site did not exist
- ArcGIS automates this task

## What is ArcGIS?

- ArcGIS is a collection of graphical information system software products sold by ESRI
- See _[http://www.esri.com/software/arcgis/index.html](http://www.esri.com/software/arcgis/index.html)_
- Software to produce maps
- Network locations
- Contour maps (e.g., concentration)
- Able to store and query on site meta-data
- Simplifies complex spatial analyses

## PM2.5 FRM Locations

## Criteria #1: 3-year Average PM2.5 Concentrations 

***Criteria #1: 3-year Average PM******2.5****** Concentrations****** ***

## Site Meta Data

## Simplified Example

- The task:  Evaluate the relative value of each of the over 1200 PM2.5 FRM sites
- Disclaimer:  This example is provided for illustrative purposes and does not reflect a detailed analysis (i.e., don’t use it!)

## Criteria #1: 3-year Average PM2.5 Concentrations 

## Criteria #2:  Spatial Coverage

## Criteria #3:  Error in Estimating

## Excerpt From Decision Matrix

## Example Ranking of PM2.5 Sites

**Disclaimer:**
- This example is provided for illustrative purposes and does not reflect a detailed analysis (i.e., don’t use it!)