# Presentation: 327796

## MRPO Nitrate and Organic Speciation Special Studies

- Donna Kenski
- National RPO Technical Meeting
- Dallas, Dec. 3-4, 2002

## Bondville

- Seney

## Slide 3

## Slide 4

## Key Components at Bondville

- Dasgupta monitor: measures gaseous nitric acid, sulfur dioxide, and ammonia (estimated limits of detection 10, 15 and 100 parts per trillion by volume, respectively) for a 15 min period, and then particulate nitrate, sulfate, and ammonium for the next 15 min period.
- Photolytic (true) NO2 and NOy
- Collocated gravimetric PM2.5, continuous PM2.5, speciated 24-hour PM2.5, continuous EC/OC, ozone, and meteorology (temperature, relative humidity, wind speed and direction, precipitation).
- 24-hour and 6-hour denuder samples

## More detail on Dasgupta

- PM2.5 size selector
- Particles collected by humidification
- Gases collected by wet denuder
- Both particles and gases analyzed by IC
- Ammonia/ammonium analyzed in separate detector, using porous membrane and conductivity detector

## Current Status and Schedule

- Dasgupta, NO2, Noy will be deployed in January, 2003
- Sampling to continue for at least one calendar year
- Challenges:  wintertime measurements with wet denuders, full time use of instruments usually used in shorter-term studies

## Particle collector

## Slide 9

## What will we learn?	

- What controls the formation of nitrate: HNO3 or NH3:
- HNO3(g) + NH3(g) --> NH4NO3(s)
- What effect will reductions in SO2 and SO4 have on NH4NO3 : additional NH4 available from SO2 reductions could increase NH4NO3
- Diurnal variations in HNO3 and NH4 may lead to answers about sources

## Indicator SpeciesExcess Ammonia (Blanchard, et al, 2000) and Gas Ratio (Ansari and Pandis, 1999) 

- Excess Ammonia

- Gas Ratio

- EA < 0	NH3-limited
- EA > 0.1	HNO3-limited

- GR < 0.4	NH3-limited
- GR > 1.5	HNO3-limited

## Slide 12

## Organic Carbon at Seney

- Organic matter can account for 50% or more of particle mass in summer at Seney NWR, Boundary Waters, and other remote pristine sites.
- Origin of OCM not obvious:
- transported urban pollution
- local biogenic
- local and/or transported forest fires
- other??
-  Source apportionment of IMPROVE data isn’t definitive (but efforts continue), hampered by too few species, degraded air far from sources, similarities among combustion sources (for quantified species).

## Seney NWR, Michigan

## Slide 15

## What is organic speciation?

- Method developed by Glen Cass, Jamie Schauer, many others
- Quartz filters, XAD-coated denuders, or PUF cartridges can be analyzed
- Filters extracted with hexane, then benzene/2-propanol, split, one fraction derivatized (to convert organic acids to methyl esters for GC/MS identification), and both fractions analyzed by GC/MS
- 100s of species can be identified, some unique tracers of sources:
- resin acids for soft wood combustion
- syringols for hard wood combustion
- levoglucosan for wood combustion
- cholesterol for meat cooking
- hopanes and steranes for diesel combustion

## Sampling plan for Seney NWR

- PI: Jamie Schauer at UW-Madison
- Quartz filters collected at Seney (2/3 day) will be composited by month and analyzed for particle phase organic species for Jan ‘02 - Dec ‘02 period
- Source apportionment will be conducted based on tracer species
- Additional daily high-volume samples were collected and a subset of those will be analyzed and apportioned
- Selected molecular markers will be analyzed for single-compound carbon isotope ratios
- Interim report due Jan. 1 2003, final Nov. 1 2003