# Presentation: 042286

## Precursor Gas Monitoring  Overview

- Joann Rice
- U.S. EPA, Office of Air Quality
- Planning and Standards
- National Air Quality Conference
- San Francisco, CA
- February 14-17, 2005

## What happened to “Trace Gas” Monitoring?

- What was ***Trace Gas*** Monitoring is _now_ ***Precursor Gas*** Monitoring
- Why the name change?
- Better reflection of the type of monitoring data to be collected
- Precursors to PM and O3

## Presentation Topics

- What we mean by “precursor gas monitoring” and how it is different from conventional NAAQS (National Ambient Air Quality Standard) monitors
- Why we need precursor gas monitoring
- The OAQPS precursor gas monitoring team
- What the team is doing to support monitoring program implementation
- Preliminary results
- Next steps

## Precursor Gas Monitoring

- High sensitivity monitoring at reduced concentrations for carbon monoxide (CO), sulfur dioxide (SO2), and reactive oxides of nitrogen (NOy)
- Lower Detectable Level (LDL)
- CO  ~ 60 ppb
- SO2  ~ 0.06 ppb
- NOy ~ 0.04 ppb
- Linear range great enough to also support NAAQS monitoring if needed
- Digital data capability to reduce errors and increase resolution

## Precursor Gas Monitoring

- Commercial monitors are available
- Thermo, Teledyne-API, Ecotech, ...
- Enhancements to CO monitors
- Sample stream dried with permeation dryer
- Frequent auto-zero capability (once per hour)
- Ultra-sensitive detector
- Enhancements to SO2 monitors
- Higher intensity source lamp - increased detector sensitivity
- Increased length of optic bench
- Better NO/NO2 rejection ratio (200:1)

## Enhancements to NOy monitors
Increased pumping speed
Detector cooled to reduce background
Increased ozone production 
Evaluating procedures for NOy calibration 
Need to use species beyond NO and NO2 for determination of converter efficiency
Use of n-propylnitrate (NPN) gas 
Consideration of nitric acid

- Increased pumping speed
- Detector cooled to reduce background
- Increased ozone production
- Evaluating procedures for NOy calibration
- Need to use species beyond NO and NO2 for determination of converter efficiency
- Use of n-propylnitrate (NPN) gas
- Consideration of nitric acid

**Precursor Gas Monitoring**

## Use of continuous monitors to: 
Support advanced multiple pollutant monitoring in urban & rural areas for the National Ambient Air Monitoring Strategy (NAAMS)
Building the infrastructure 
Develop emission control strategies
Air quality model evaluation 
Rural monitoring of precursors for background transport
Source apportionment and other observation-based models
Support long-term health and epidemiology studies

- Support advanced multiple pollutant monitoring in urban & rural areas for the National Ambient Air Monitoring Strategy (NAAMS)
- Building the infrastructure
- Develop emission control strategies
- Air quality model evaluation
- Rural monitoring of precursors for background transport
- Source apportionment and other observation-based models
- Support long-term health and epidemiology studies

**Why Precursor Gas Monitoring is Needed**

## Why Precursor Gas Monitoring is Needed

- Progress in science and technology to address complexity

**Why Precursor Gas Monitoring is Needed**

- Need precursors to support research data uses and the general support of atmospheric sciences

## OAQPS Precursor Gas Monitoring Team

**Joann Rice:** Methods Team Lead
**Tim Hanley:**  Monitoring Program Lead
**Kevin Cavender:**  NOy Method
**Dennis Mikel:**  CO Method
**Anna Kelley/Michael Papp:** Quality Assurance
**Solomon Ricks:** SO2 Method
**Nealson Watkins:** Data Management
**Lewis Weinstock:** New Monitoring
- 	Technology Transfer
**Keith Kronmiller:** Contractor Support (Mantech)

## OAQPS Precursor Gas Monitoring Team

**OAQPS Precursor Gas Monitoring Team**

**Products and deliverables**
- Short method summaries
- Instrument testing and evaluation – lab & field
- Standard Operating Procedures (SOPs)
- Technical Assistance Document (TAD)
- Technology Transfer and Training
**Information located at ****www.epa.gov/ttn/amtic/precursor.html**

## Data Management

- Testing precursor gas systems with two commercially available data management systems
- ESC 8832 data logger with EDAS software
- DR DAS digital data acquisition system with Envidas
- Digital data transfer
- Reduces errors and noise in analog signal
- Provides diagnostic data useful for data validation and instrument troubleshooting

## Quality Assurance (QA)

- Data Quality Objectives (DQOs)
- Planned for completion Fall 2005
- Data Quality Indicators (DQIs)
- Precision, bias, sensitivity, completeness, comparability
- Measurement Quality Objectives (MQOs)
- Includes DQIs and method specific Quality Control (QC)
- Redbook revisions (in progress)
- Data validation templates, QC and QA
- National Performance Audit Program (NPAP)
- Technical System Audits (TSAs)
- Performed by the regions once every 3 years

## Technology Transfer and Training

- Purpose is to provide information to State, Local and Tribal agencies for implementation of the precursor monitoring network
- Technology Transfer Topics
- Background – why monitoring is needed
- Presentation of individual methods and principles of operation
- Explanation of statistical evaluations (LDL, precision, bias, etc.)
- Hardware considerations and technical issues
- Information Technology
- Data management and digital data transfer considerations
- Quality Assurance
- Timing
- Research Triangle Park, NC workshop under development for spring or summer 2005
- Also considering updates via newsletters, satellite broadcasts, and web-based training

## Preliminary Lab Results

**Precision (coefficient of variation)**
- CO 	10 - 15%
- SO2 	1 - 3%
- NO/NOy	2.5%
**Bias**
- CO 	15 - 30%
- SO2 	5 - 10%
- NO/NOy 	10%
**Lower Detectable Level**
- CO  	~ 60 ppb
- SO2  	~ 0.06 ppb
- NOy 	~ 0.04 ppb
**Linearity**
- CO 	y = 1.002x + 11.07 ppb 	r2 = 0.99950
- SO2	y = 0.999x + 0.449 ppb 	r2 = 0.99990
- NOy 	y = 1.0032x – 0.0327 ppb 	r2 = 0.99999

## Hourly Ambient Monitoring Data

**Courtesy of SEARCH Public Archive at http://www.atmospheric-research.com/searchhome.htm**

**Birmingham, Alabama **

_**Concentrations in ppb**_

**Centreville, Alabama**

**Lower Detectable Level**
- NOy 	~ 0.04 ppb
**Linear Range**
- NOy 	0 - 200 ppb (analog)
- NOy 	0 - 500 ppb
- (expected digital)

## Hourly Ambient Monitoring Data

**Courtesy of SEARCH Public Archive at http://www.atmospheric-research.com/searchhome.htm**

_**Concentrations in ppb**_

**Birmingham, Alabama **

**Centreville, Alabama**

**Lower Detectable Level**
- CO            ~ 60 ppb
**Linear Range (multiple)**
- CO            0 - 5000 ppb

## Hourly Ambient Monitoring Data

**Courtesy of SEARCH Public Archive at http://www.atmospheric-research.com/searchhome.htm**

_**Concentrations in ppb**_

**Lower Detectable Level**
- SO2  	~ 0.06 ppb
**Linear Range (multiple)**
- SO2  	0 - 100 ppb

**Birmingham, Alabama **

**Centreville, Alabama**

## Next Steps

**Next Steps**

- Products and deliverables
- Short summaries of methods complete
- Specific SOPs for OAQPS operations in progress
- CO, SO2, NOy, calibration system, data acquisition, data management and reporting
- TAD – first internal draft expected in February
- DQOs – development planned for fall 2005
- Changes to data reporting to facilitate receipt of data in AQS and AIRNow in progress
- Pilot monitoring network of ~22 sites
- Monitoring workgroup in place
- Sites to begin implementation during 2005
- Technology transfer
- Workshop under development for spring
-       or summer 2005

## Summary

- Precursor gas monitors have modifications to improve sensitivity over the standard NAAQS monitors
- Precursor gas monitoring is needed to support multiple objectives
- NAAMS, emission control strategies, health effects studies, atmospheric research
- OAQPS has a team that is focused on understanding the technologies, capabilities, limitations and providing a variety of technical support to monitoring agencies
- A “Pilot” network is being established in 2005 to further demonstrate and understand available precursor gas monitoring technologies and urban/rural concentrations
- Precursor gas monitoring information is located at:
**www.epa.gov/ttn/amtic/precursor.html**