3506C05/C22 – Draft Final Report
Study of Air Quality Impacts Resulting from Prescribed Burning
- Focus on Sub-Regional PM2.5 and Source Apportionment -
Sponsored by
Installation Management Agency South-East Regional Office (IMA-SERO), FortMcPherson,
and the United States Army Infantry Center (USAIC), Fort Benning, Georgia
Subcontract No. NC03-005SUB01, and
Subcontract No.GS01-079SUB01
Prepared for
Engineering and Environment, Inc. (EEI)
195 South Rosemont Road, Suite 118
Virginia Beach, VA23452
Prepared by
Karsten Baumann
School of Earth and Atmospheric Sciences
Georgia Institute of Technology
Atlanta, GA30332-0340
March 31, 2005
ACKNOWLEDGEMENT
The Prescribed Burn Study was born out of the Fall line Air Quality Study (FAQS) and is a joint effort of the Georgia Institute of Technology’s Schools of Earth and Atmospheric Sciences (EAS) and Civil and Environmental Engineering (CEE). This part of the Study here is a continuation of the Pilot Study supported by the US Department of Defense/Army Construction Engineering Research Laboratories (CERL) through the DOD-EPA-State Region 4 Pollution Prevention Partnership. The financial support provided for this Study Phase II by the U.S. Army Infantry Center (USAIC) at FortBenning, and the Southeast Regional Office, Installation Management Agency, (SRO-IMA) at FortMcPherson is gratefully appreciated.
Principal Investigator: Dr. Karsten BaumannEAS
Co-Principal Investigators: Dr. Mei ZhengEAS
Dr. Michael ChangEAS
Dr. Armistead Russell CEE
Contributors:Dr. Mike BerginDr. Don Blake
Dr. Carlos CardelinoDr. Zohir Chowdhury
Mr. Mark ClementsDr. Eric Edgerton
Mr. Jeff GarnettMr. Sangil Lee
Dr. Sam ManomaiphiboonDr. Luke Naeher Dr. Talat Odman Mr. James Rebholz
Dr. James SchauerDr. Rebecca Sheesley
Ms. Amy SullivanDr. Alper Unal
Dr. Rodney WeberMr. Wes Younger
This work was only possible through the close collaboration of Georgia Tech with expert scientists and research personnel from the Universities of Georgia (UGA) Athens,Wisconsin (UWI) Madison, and California, Irvine (UCI). Valuable contributions were provided by Dr. Luke P. Naeher and his group from UGA’s Department of Environmental Health Sciences, by Dr. James J. Schauer and his group from UWI’s State Laboratory of Hygiene, and by Dr. Don Blake and his group from UCI’s Department of Chemistry, who analyzed the whole-air VOC canister samples. The GC/MS laboratory analyses of the study’s samples were performed by Dr. Rebecca Sheesley, and Mr. Jeff DeMinter from UWI.
Mr. James Rebholz and Mr. Jeff Garnett from the UGA team serviced the samplers that were deployed at the relevant regulatory monitoring sites, i.e. the Fort Benning Junction site in MuscogeeCounty, and the Bungalow Road site in RichmondCounty, Augusta, representing the ambient samples. They alsoconducted the aerosol sampling directly at the prescribed burn source sites.
Dr. Eric Edgerton from Aerosol Research & Analysis Inc. (ARA) kindly provided XRF trace elements data from the prescribed burning source samples.
Mr. Wes Younger and Dr. Zohir Chowdhury helped with the set up and preparation of the sampling equipment at the two EPD sites.
The results of this study were analyzed and evaluated via application of Chemical Mass Balance (CMB) modeling and source apportionment by Mr. Sangil Lee, a Ph.D. candidate from the School of Civil and Environmental Engineering (CEE) at Georgia Tech.
Dr. Kasemsan (Sam) Manomaiphiboon, also from CEE, assisted in the regression supported Principal Component Analysis (PCA) of the 3-year data set combining prescribed burn activities with meteorological and fine PM mass observations on a sub-regional scale.
Further special recognition and thanks are due to the following individuals for their work in securing funding for the study, in providing technical and logistical support to the science team, or in providing additional information in support of the study analysis and evaluation:
Mr. Mark Clements, Mr. Rick Sinclair and Ms. Manette Messenger from the Installation Management Agency South-East Regional Office (IMA-SERO) at Fort McPherson, Georgia;
Mr. John Brent and Ms. Polly Gustafson from the Environmental Management Division (EMD) of the USArmyInfantryCenter (USAIC) at Fort Benning, Georgia;
Mr. Bob Larimore, Mr. Jack Greenlee, Mr. Tom Hutcherson, Mr. Rick Johnston, and Mr. James Parkerfrom Fort Benning’s Land Management Branch (LMB);
Mr. Allen D. Braswell, and Mr. Steve Willard from Fort Gordon’s LMB;
Ms. Nora Chiong from Engineering & Environment Inc. (EEI) in Virginia Beach, Virginia;
Mr. Daniel Chan and Mr. Alan Dozier from the Georgia Forestry Commission (GFC) in Macon, Georgia;
Mr. Kit Redmond and Dr. Susan Zimmer-Dauphinee from Georgia’s Department of Natural Resources (DNR), Environmental Protection Division (EPD).
TABLE OF CONTENTS
1 EXECUTIVE SUMMARY...... 1
2 INTRODUCTION...... 4
3 METHODOLOGY...... 6
3.1 Sample Collection…...... 6
3.1.1 Discrete Sampling of Aerosol Species...... 7
3.1.2 Instantaneous Measurements of Gaseous Emissions...... 11
3.2 Calculation of Ambient Aerosol Concentrations...... 11
3.3 Sample Analyses and Data Quality...... 13
3.3.1 Gravimetry ...... 13
3.3.2 Ion Chromatography (IC)...... 15
3.3.3 Elemental and Organic Carbon (ECOC)...... 16
3.3.4 Uncertainties of PM2.5 Mass, ECOC and Trace Elements Concentrations...... 18
3.3.5 Gas Chromatography - Mass Spectrometry (GC-MS)...... 23
4 RESULTS AND DISCUSSION...... 23
4.1 Sensitivities of the Local Source-Receptor Relationship...... 24
4.1.1 Consequences of Short-term NAAQS Exceedances on Non-attainment...... 24
4.1.2 Sensitivities from Linear Regression-PCA...... 28
4.2 General Ambient Measurement Conditions in April 2004...... 30
4.2.1 General Meteorological and Ambient Air Quality Conditions...... 31
4.2.2 Ambient Aerosol Characterization...... 33
4.2.3 Biomass Burning and Secondary Organic Aerosol (SOA)...... 38
4.2.4 Estimating SOA in Ambient Samples...... 40
4.3 Emission Measurements and Factors...... 43
4.3.1 Gaseous Emissions...... 43
4.3.2 Chemical Composition of Aerosol Emissions...... 45
4.3.3 Emission factors (EF)...... 50
4.4 Preliminary CMB Results and Comparison with Literature...... 54
5 REFERENCES...... 55
List of Figures
Figure 1: Outline of north-central Georgia with fire occurrences in private forests and on Forts Gordon and Benning during the years 2001 and 2002, and ambient measurement sites.
Figure 2: Set up of sampling equipment at the ambient monitoring and burning source sites.
Figure 3: Three-channel PCM for discrete measurement of PM2.5 mass and composition.
Figure 4: Linear regression of values from Table 4.
Figure 5: Schematic of the thermal-optical transmission (TOT) instrument for the analysis of elemental and organic carbon (EC+OC) in PM25 quartz filter samples [Birch and Cary, 1996].
Figure 6: Thermogram of a quartz filter sample with front oven temperature, two differently amplified FID signals, and the He/Ne laser transmittance signal. Note the final peak is from the internal CH4 calibration.
Figure 7: Linear regression of PM2.5 mass concentration in mg m-3 measured at various burn sites at SRS, Forts Gordon and Benning before and during conducts of prescribed burning.
Figure 8: Linear regressions of OC and EC concentrations in g m-3 from HVS and PCM measurements at the ambient (top) and source sites (bottom), corresponding to data in Table 6 including the SVOC from the PCM’s backup filter.
Figure 9: Comparison of measured and predicted [GFC, 2003] meteorological parameters, fires and 24h [PM2.5] from OLC compared with Griffin, Macon, and Augusta for 5 weeks in fall 2001.
Figure 10: Correlation of 24 h average [PM2.5] at OLC with total acres burnt, considering the fire locations, as well as various measured and forecasted meteorological parameters.
Figure 11: Linear regressions of 24h [PM2.5] in g m-3 of EPD’s Health Dept. site (top) and Cusseta Road site (bottom) vs. OLC for period 2001-2003 (left) and Oct/Nov 2001 (right).
Figure 12: Annual mean of [PM2.5] for EPD’s FRM network sites at Atlanta (Kennesaw to Gainesville), Macon, Columbus, Augusta, and coastal sites (Savannah, Brunswick), compared with FAQS network sites (note: operational only since June/July 2000!).
Figure 13: Hourly averaged meteorological parameters, O3 and PM2.5 concentrations at EPD’s ambient monitoring sites in Augusta and Columbus for period April 12-17 (left) and 25-30 (right).
Figure 14: Mixing ratios of reactive gases from discrete PCM denuder samples taken at FortGordon background on 4/13, at EPD’s Augusta site (4/13-18), at FortBenning’s background on 4/27, and at EPD’s Columbus site (4/27-30).
Figure 15: Fine PM mass composition with Other incl. Na+, Ca2+, K+, Cl-, major metal oxides, LOA as the light organic acids, and OOE as Other Organic Elements (equals unidentified mass).
Figure 16: Charge balance of ambient PM2.5 samples taken at FortGordon background on 4/13, at Augusta EPD (4/13-18), at FortBenning background on 4/27, and Columbus EPD sites (4/27-30).
Figure 17: [OC] vs. [EC] from the two urban EPD sites, Augusta and Columbus, and the more rural forested sites on Forts Gordon and Benning, with linear regression of selected samples dominated by primary OC, yielding (OC/EC)p = 4.8 ±0.7 and non-combustion OCp of ~0.5 ±0.3 g m-3.
Figure 18: Comparisons of normalized excess mixing ratios (NEMR relative to CO) between flaming and smoldering emissions from prescribed burning
Figure 19: Emission mixing ratios of reactive gases (i.e. above ambient background) from PCM samples taken at FortGordon’s TA 25 (331 acres) and TA 24 (345 acres) on April 15 and 16, and at FortBenning’s TA F4-E (204 acres) and TA F4-W (381 acres) on April 28 and 29, respectively.
Figure 20: Fine PM mass composition with Other inorganic ions dominated by K+ but incl. Cl-, Na+, and Ca2+, MetOx incl. major metal oxides and other XRF elements, LOA as the light organic acids, and OOE as Other Organic Elements (equals unidentified mass).
Figure 21: Charge balance of smoke PM2.5 samples taken at FortGordon on April 15 and 16, and at FortBenning on April 28 and 29, 2004, with overall average.
Figure 22: Comparison of bulk PM2.5 chemical composition of emissions from this in situ study with different laboratory and fireplace-type experiments.
Figure 23: Comparison of NMHC emissions assuming a biomass C-content of 42.6 %.
Figure 24: Source apportionment of major sources incl. biomass burning using different POC profiles to [OC] measured at ambient EPD sites during April 2004.
List of Tables
Table 1: Sampling dates, locations and purposes for PM2.5 sample collection during the field measurement period 12 April to 1 May 2004. Burn source samples are highlighted grey.
Table 2: PCM channel configurations used at the ambient and source locations.
Table 3: Set up of dynamic blank test for determining the CM denuder efficiency.
Table 4: Precision of PM2.5 mass concentration from PCM Teflon filter mass of channels 1 and 2.
Table 5: Accuracy, relative and absolute precision (P) achieved for the laboratory IC used during the analyses of the samples collected.
Table 6: Comparison of ECOC, Total Carbon (TC), and OC/EC ratio measured simultaneously by the HVS and PCM samplers at the ambient and source sites; with slopes, intercepts and correlation coefficients R2 (incl. standard errors) for individual linear regressions at 95 % confidence level.
Table 7: Summary of PCM Data Quality Indicators (DQI) for gas- and particle-phase species determined during the analysis of samples collected in 2004.
Table 8:Comparison of elemental PM mass concentrations of smoke samples collected near prescribed burning sources that were analyzed by two distinctly different analytical methods, i.e. energy-dispersive X-Ray Fluorescence (ED-XRF), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS).
Table 9: Daily 24 h means, standard deviations based on ½ h means, and ½ h maxima [PM2.5] in μg/m3, at Columbus, OLC; and completeness of records for that particular day in percent.
Table 10: Measured and modeled (from GFC forecast) input variables and their meanings.
Table 11: Sensitivities of observed and forecasted parameters on ambient [PM2.5] at OLC.
Table 12: Sample information and mixing ratios of individual samples, incl. averages and standard deviations of all samples depicted in Figure 14.
Table 13a: PM2.5 mass concentrations of major ionic species, incl. semi-volatile (SV) fractions.
Table 13b: PM2.5 mass concentrations of major metal oxides, XRF elements, ECOC, total and unidentified mass, as well as OM/OC and OC/EC ratios.
Table 14:Contributions of identified species to total mass concentration.
Table 15: Uncertainties of identified species and overall mass closure relative to total mass.
Table 16: Measured ECOC concentrations and OC/EC ratios of samples dominated by primary OC (OCp) under relatively low maximum [O3].
Table 17: Measured ECOC concentrations and OC/EC ratios of samples influenced by both primary and secondary OC (OCs) with corresponding maximum [O3] and calculated OCp and OCs fractions from above EC tracer method.
Table 18: Normalized Excess Mixing Ratios (NEMR relative to CO) of gaseous emissions from flaming and smoldering stages of prescribed fires
Table 19: Emission mixing ratios from Figure 19, including sample start times and durations.
Table 20a: PM2.5 mass emissions of major ionic species, incl. semi-volatile (SV) fractions.
Table 20b: PM2.5 mass emissions of major metal oxides, XRF elements, ECOC, total and unidentified mass, as well as OM/OC and OC/EC emission ratios.
Table 21:Contributions of identified species to total fine PM mass emissions.
Table 22: Uncertainties of identified species and overall mass closure relative to total emitted mass.
Table 23: Overview of average and standard deviation (STD) of the chemical composition of particle-phase emissions from prescribed burning with detailed elemental species that are relevant for CMB modeled source apportionment (V, Cr, Co, Ni, Ga, Ge, Mo, Ag, Cd, Sb, Ba, Li, and Be were below blank level or below DL).
Table 24a: Averages and standard deviations of Emission Factors (EF) of particle phase emissions from 7 flaming and 7 smoldering stages in g or mg per kg biomass burnt.
Table 24b: Averages and standard deviations of Emission Factors of gas phase emissions from flaming and smoldering stages in g or mg per kg biomass burnt.
Table 25:FortBenning emission inventory of criteria pollutants for FY 2002.
1
1 EXECUTIVE SUMMARY
Guided by the Endangered Species Act (ESA), the DOI through the Fish and Wildlife Service mandates that most army and air force bases in the South-Eastern US use prescribed burning to maintain the health of its native long leaf pine forest and thus protecting the habitat of the endangered red-cockaded woodpecker. Other installations across the Nation utilize prescribed burning to control invasive plants, which would otherwise endanger the habitat of other creatures. Due to the direct benefits of recreating and maintaining a healthy fire ecology, privately owned land is also managed by prescribed burning, amounting to more than 1 million acres burnt per year in Georgia alone. Releasing primary and secondary gas- and particle-phase pollutants, biomass burning however, can contribute significantly to already burdened local and regional air pollutant loads, challenging the air quality standards mandated by the EPA and the Clean Air Act (CAA).
In recognition of the conflicting requirements between the ESA and CAA statutes, the “Pilot Study of Air Quality Impacts Resulting from Prescribed Burning on Military Facilities” was initiated and sponsored by the DOA/CERL in support of the DOD Pollution Prevention Partnership. In order to build upon the findings of that study and fill in the gaps in our understanding of local to regional impacts from prescribed burning and to better estimate potential contributions from these open burning activities to local air quality, a Phase II of the Pilot Study was initiated and conducted in spring of 2004. In order to further develop potential benefits for the public health and welfare of the State of Georgia in meeting air quality standards, and in response to the need for guidance in the development of a Smoke Management Plan for Georgia, the following objectives were pursued in this effort:
- To identify days when 24 h PM2.5 mass concentrations measured during past years at the states’ regulatory monitoring and FAQS OLC research sites near FortBenning (Muscogee County, GA) were potentially influenced by prescribed burning.
- To estimate upper limit contributions from the burn activities to the observed measurements under consideration of their sensitivities to the meteorological forecast products from the Georgia Forestry Commission (GFC).
- To ultimately help focus and improve GFC forecasts toward minimal air quality impacts.
- To determine Emission Factors (EF) of most important gaseous and particulate pollutants emitted by this type combustion and compare them with EF from the incomplete combustion of other bio fuels that are available in the literature.
- To determine the source profile of the POC molecular markers emitted by prescribed burning, which then will be subjected to the CMB model along with profiles representing other major sources of potential influence to the observed concentrations.
- To estimate the contribution of prescribed burning emissions to the PM2.5 concentration observed at the regulatory monitoring sites of the GA Environmental Protection Division (EPD) at Richmond and Muscogee counties, i.e. the monitoring sites nearest to the Forts.
Major Findings
Short-term violations of the 24h National Ambient Air Quality Standard of 65 g m-3observed locally at a site near FortBenning, caused exceedance of the annual NAAQS for [PM2.5] of 15 g m-3 in 2001.
EPD’s regulatory monitoring site at the Columbus Health Department, which is 6 km further away from Fort Benning than their Cusseta Road site, benefits from the greater distance to the burn activities by recording ~20 ±4 % lower [PM2.5] for the 2001 – 2003 period.
A combined principal component and regression analysis corroborated earlier indications that the local [PM2.5] is most sensitive both to measured and GFC forecast parameters, in particular daily max-min temperature difference, wind speed, and probability of precipitation; burning activities on Fort Benning themselves resulted in an estimated contribution to the local [PM2.5] of ~2 g m-3 per 1,000 acres burnt.
Normalized Excess Mixing Ratio (NEMR) relative to CO were determined for emissions from flaming and smoldering prescribed fires, indicating higher alkenes, ethyne (acetylene), organic nitrates for the former, andhigher alkanes, biogenic (, -pinenes and isoprene), halogenic and aromatic hydrocarbons emissions for the latter, respectively.
The NH3/CO ratio of 0.6 ±0.3 and 20 ±16 ppbv/ppmv for flaming and smoldering, respectively, agrees well with values found in recent literature.
However, both potassium and chloride emissions are significantly higher in our case, indicating the important difference in fuel mix relative to other investigations, in that our fuels contained significantly higher amounts of chlorophyll containing materials.
Organic Carbon (OC) was the largest contributor to PM2.5 emissions with 60 ±19 %, and an OC/EC emissions ratio of 18.5 ±14, which compared well with laboratory type simulations of the open burning of loblolly pine and wire grass / loblolly pine needle mix, resembling most closely the fuel burnt in our study.
Emission Factors (EF) in g-species to kg-biomass for 55 gas-phase and 33 particle-phase constituents were determined for flaming and smoldering stages of prescribed burning, that will significantly help improve emission inventories, and be of great value for air quality modeling and management efforts in numerous planning and development applications.