# Presentation: 438307

## IMPROVE Ion Study Plan

- Presented by Marc Pitchford to the
- RPO Technical Groups
- Dallas, TX  12/3/02

## IMPROVE nitrate

## IMPROVE nitrate %

## Routine IMPROVE sampling/analysis

- 4 modules
- Module B for PM2.5 ions
- Carbonate-coated denuder removes acidic gases
- Nylon filter
- Extracted with carbonate/bicarbonate solution (anion IC eluent) for anion analysis – used for a number of years
- Extracted with water for anion + cation analysis –  used in recent year to remove a sodium interference from IC eluent
- Analyzed by IC

## Apparent Change in Nitrate Trend Glycerin Added to the Denuder in 1996? 

- Apparent Change in Nitrate Trend Glycerin Added to the Denuder in 1996?

## Sampling and extraction issues

- What happens to NH4NO3 volatilized from nylon filters?
- HNO3 trapped? Decrease in water extraction efficiency?
- NH3 lost?  Bias in measured PM2.5 ammonium?
- Does water efficiently extract nitrate from nylon filters?
- Nitric acid collected on nylon filters is not efficiently recovered with water extraction
- Other nitrates efficiently extracted

- NH3(g) + HNO3 (g)  NH4NO3(p)

## IMPROVE ion special study goals

- Determine characteristics of ionic aerosol present at selected IMPROVE sites
- Ionic composition and size distribution by region & season
- Gas-particle distribution of Nitric acid/nitrate & ammonia/ammonium
- Evaluate IMPROVE ion sampling and analysis approach
- Denuder efficiency
- Nitrate volatilization on Teflon filters with/without denuders
- Ammonium bias on nylon filters
- Filter extraction efficiency

## IMPROVE Ion Study Approach

- Field Studies
- Six 30-day studies
- Various denuder/nylon filter/ denuder arrangements
- MOUDI sampling for ion size distributions
- Laboratory Studies
- Denuder efficiency testing for newly coated and used denuders as a function of relative humidity
- Filter extraction efficiency testing for samples collected in Ft. Collins, CO & Davis, CA using deionized water & sodium carbonate/sodium bicarbonate solution

## IMPROVE ion study field plans

- Six 1-month studies
- Bondville – February 2004
- San Gorgonio – March/April 2003 & July 2003
- Brigantine – November 2003
- Sequoia – February 2004
- Grand Canyon – May 2004

## IMPROVE Network & Ion Study Sites

- Bondville

- Brigantine

- Grand Canyon

- Sequoia

- San Gorgonio

## IMPROVE ion study field plans

- Equipment
- 12-hour & 24-hour sampling with various URG denuder/filter pack arrangements using nylon & Teflon filters
- 48-hour MOUDI sampling for ion size distributions
- Analyses
- Major particulate anions (NO3-, Cl-, & SO4=) and cat ions (Na+, K+, NH4+, Ca++, & Mg++) by IC & comparing water versus basic IC extract solution from the filter pack and MOUDI samples
- Gaseous ammonia and nitric acid from denuders

## Modules 1 and 2

- Daily, 24 hr samples
- Compare nylon filter extraction (H2O vs. carbonate/bicarbonate)
- Examine loss of HNO3 and NH3 from nylon filter
- Provide gas-particle phase distribution for N(-III) and N(V)
- Module 3
- Day/night sampling
- Replicates for precision
- Aerosol acidity/NH4NO3 volatilization on Teflon filters

## Recent Preliminary Findings

- Nylon filter extraction by water?
- EPA study of fall filters collected at numerous STN and IMPROVE sites gave average 90% extraction efficiency
- CSU Fort Collins samples (Spring 2002) yielded no evidence of lower water extraction efficiency
- Fate of volatilized NH4NO3?
- EPA study indicated significant ammonia loss

##  Possible Additional Monitoring for IMPROVE Ion Study

- Particle Into Liquid System (PILS)
- High time resolution ion concentrations
- During the Yosemite study PILS data showed that the dominate nitrate compound can change quickly between ammonium nitrate and sodium nitrate (produced by nitric acid reacting with sea salt)