Karsten Baumann 1 , J.J. Schauer 2 , D.R. Blake 3 , S.R. Mitchell 4 J.M. Fort 1 , E.S. Edgerton 1

1. Gas and Fine Particle Species Emissions from Prescribed Burning in Managed Forests of the South-Eastern United States Karsten Baumann1, J.J. Schauer2, D.R. Blake3, S.R. Mitchell4 J.M. Fort1, E.S. Edgerton1 • Atmospheric Research & Analysis, Inc., Research Triangle Park • Civil & Environmental Engineering, University of Wisconsin, Madison • Department of Chemistry, University of California, Irvine • Nicholas School of the Environment, Duke University, Durham Special Thanks to Jeff DeMinter, Steve Geis (U of WI, Madison), Brent Love, Simone Meinardi (U of CA, Irvine), Susan Cohen and all MCBCL EMD and ARA staff https://dcerp.rti.org

2. Objectives within DCERP Describe and improve our understanding of Transport of critical air pollutants on local and regional scales, Air quality impacts from emission sources on/off the Base, and Prescribed burning (PB) emissions from forest management. Provide information on Influence of fuel moisture? Benefits of mechanical thinning? Canopy Fumigation Flaming Fuel being hydro-axed Smoldering

3. Influence of fuel pre-treatment (mechanical thinning by hydro-axing) on direct (primary)in situ emissions and emission factors (EF) O3 SOA POA CO CO2 VOC NOx PM, POA Toxics Understanding the PB Emission Source

4. Experimental Approach Collect aerosol emission samples upwind and near PB source of treated and untreated fuels. treated untreated

5. Analytical Methods Measured Species Summary Integrating measurements upwind (background), PB source treated and untreated (flaming/smoldering). Spectrum of species including major alkaline/acidic gases, PM2.5 ions, EC, OC, crustal/metallic elements, >40 VOC species, >100 POC species. *) SOA Tracers include methylerythritol, pinic/pinonic acid, oxopentanoic acid

6. MCBCL Location PB experiment sites at Marine Corps Base Camp Lejeune (MCBCL) capture vegetation gradient from semi-mesic loblolly pine forest (HA, MF, RB) to wet-mesic loblolly-longleaf pine forest (IE-south) to pond pine pocosin (IE-north). CTRL HYAX RB MF HA OM = Organic Matter in soil IE-north IE-south IE-south, HA in 2010 IE-north, MF, RB in 2011 Simultaneous HYAX & CTRL

7. Impressions from IE-north on 3/3/11 Mechanically thinned (hydro-axed) fuel Control fuel

8. Gaseous Emissions • Highest variability in acidic gases and isoprene • Average HYAX very similar to average CTRL • Fuel dependent sensitivities to be investigated

9. Gaseous EF Comparison • More reactive species vary up to factor 10 • Best agreement with other in situ ground data • African savannah aircraft data mostly lower

10. PM2.5 Emissions • Drier fuels trend to systematically higher EF • HYAX emissions consistently lower than CTRL • Fuel dependent sensitivities to be investigated

11. PM2.5 Species EF Comparison • PM2.5, OC, EC agree within factor of 2-3 • Large discrepancies in ionic species EF • HYAX EF consistently lower than CTRL • Interesting differences in ICPMS vs. XRF

12. EF Comparison with AP-42* *EPA, AP-42, Fifth Edition, Vol. I (13): Miscellaneous Sources, 13.1 Wildfires and prescribed burning, Suppl. B, October, 1996; assuming 35/65 long/short needle fuel mix and 2:1 smolder:flaming weighting • EF from both fuel types are lower than AP-42, with EF for CO/CH4 significantly lower. • Mechanically thinned (HYAX) fuel yields lower PM2.5-EF while AP-42 and CTRL are similar. • Average CO/CH4-EF from HYAXfuel is higher than CTRL and less variable (narrower range).

13. Measured Fuel Consumption (FC) • More material is being consumed when fuel is hydro-axed (HYAX) and the majority of that material is woody. • Consumption of the available fuel at untreated (CTRL) sites is less than hydro-axed (HYAX) sites. • Applying average CTRL-FC to total 44 km2 burned in MCBCL forests in 2009, yields annual fuel removal of 18,480 tons.

14. PB Emissions Relative to Other MCBCL Sources Boilers Generators Training pits Engine test stands • Applying EF from both untreated and treated fuel beds to the 18,480 tons of fuel removed in 2009, yields annual total emissions for comparison. • Hydroaxing the same forest area prior to PB, would have removed 4x more fuel but at the cost of correspondingly higher emissions!

15. Summary and Outlook • While average gaseous EF are similar, most PM2.5 species EF from hydro-axed fuels are lower than those from untreated control fuels. • PB in situ emission factors are distinctly lower than lab simulation based AP-42, with similar magnitude only for PM2.5 emissions from drier control fuel. • Hydro-axe treatment yields greater availability and consumption of woody fuel regardless of fuel moisture, while moist untreated fuel yields lowest consumption. • Measurement of in situ fuel consumption improves total emission estimates for the benefit of emissions inventories and annual reporting. • Pending WSOC/LCMSMS analysis by Schauer et al. will help shed light on fast secondary PM formation processes in PB plumes (Balloon study). • In collaboration with Mitchell et al. the observed emissions variability of certain gas and POC species will be linked to soil OM and other distinct fuel data. • PM matrix effects for water soluble metals will be investigated. • Use soil elemental ratios (relative to Al) to investigate “enrichment” by the PB source process.