The contribution of biomass combustion to ambient particulate organic carbon

Transcription

1 The contribution of biomass combustion to ambient particulate organic carbon J. Collett, A. Sullivan, G. Engling, C. Gorin, P. erckes, L. Mazzoleni, A. olden, S. Kreidenweis Atmospheric Science Department, Colorado State University W. Malm National Park Service W.M. ao USDA Forest Service Funding: NPS, JFSP, SJVAPSA

2 OUTLINE Introduction Biomass combustion and its air quality impacts Molecular markers and their analysis Field Observations Yosemite summer Fresno winter More routine levoglucosan measurement Source profiles Concluding remarks

3 Fire impacts on air quality Wild and prescribed fires exert strong impact on summertime aerosol, especially in western U.S. Residential wood combustion is major contributor to winter PM episodes in some urban areas

4 SOURCE MARKERS Molecular Markers = Source Tracers Required Molecular Marker Properties Representative for source (unique) Stable in atmosphere (stable molecular structure) Detectable concentration Analytical accuracy + precision Primarily in the aerosol phase Desired Network application Semi-continuous

5 Some wood smoke markers Methoxylated phenols Guaiacol and substituted guaiacols vanillin, vanillic acid, eugenol, 2,6-dimethoxy phenol,... syringol and substituted syringols Resin Acids abietic acid, pimaric acid, Retene Monosaccharide Anhydrides (Sugar anhydrides) levoglucosan (1,6-anhydro-β-D-glucopyranose) galactosan (1,6-anhydro-β-D-galactopyranose) mannosan (1,6-anhydro-β-D-mannopyranose)

6 Sugar anhydrides Levoglucosan Cellulose thermal decomposition product Major component of wood smoke Mannosan and Galactosan Stereoisomers of levoglucosan Typical wood composition cellulose 45% Formed from hemicellulose decomposition Much less abundant than levoglucosan hemicellulose 3% lignin 25%

7 Carbohydrates C 6 12 O 6 Mol. Wt.: 18.2 C 6 12 O 6 Mol. Wt.: 18.2 C 6 12 O 6 Mol. Wt.: 18.2 O O O O O O O O O O O O O O n O O O O O O O O O O O O O O O O O O OO O Cellulose Glucose Galactose Mannose - 2 O - 2 O - 2 O C 6 1 O 5 Mol. Wt.: C 6 1 O 5 Mol. Wt.: C 6 1 O 5 Mol. Wt.: O O O O O O O O O O O O O O O Levoglucosan Galactosan Mannosan

8 Levoglucosan analysis Current analytical method GC/MS igh volume aerosol sample Spike with isotopically labeled standards Organic solvent multi-step extraction Extract concentration Chemical derivatization Need an easy, inexpensive method for sample screening/analysis and on-line measurement

9 Yosemite National Park Summer 22

10 Yosemite background Air quality in Yosemite National Park IMPROVE shows high summer-time fine aerosol concentrations Large carbonaceous PM content (> 4%) + high seasonal variability in OC Study Objectives Estimation of wildland fire contributions to ambient aerosol and regional haze

11 Yosemite composition overview PM µg/m 3 Organic fraction above 16-year average OM/OC ~ 1.8 Contemporary carbon ~88% Black C 2% Soil 6% Ions 19% Oxalate 1% Na+ 1% N4+ 4% K+ % POM 73% SO42-1% NO3-3% NO2- % Mg2+ % Ca2+ % Cl- %

12 Yosemite timeline Major OC episode in mid-august PM Fine Particle OM (µg/m³) 25 PM2.5 2 OM (TOR) /13/22 7/23/22 8/2/22 8/12/22 8/22/22 9/1/22

13 Summer 22 western fires

14 Yosemite smoke markers timeline Smoke markers also rise in mid-august igh concentrations in early Sept local fire conc. (ng/m³) Acetovanillone Vanillin Retene Pimaric Acid Dehydroabietic Acid Galactosan Mannosan Levoglucosan 2 July 14-2 July July 28-Aug 3 Aug 4-1 Aug 1-16 Aug Aug 24-3 Aug 31-Sep 5

15 Yosemite smoke apportionment Different smoke markers yield similar apportionment Primary smoke contribution is relatively small in mid-august OC peak % of OC based on Levoglucosan % of OC based on Retene % of OC based on Vanillin % of OC July 14-2 July July 28-Aug 3 Aug 4-1 Aug 1-16 Aug Aug 24-3 Aug 31-Sep 5 Source apportionment based on emission source profiles from ays et al. (22)

16 Overall apportionment 7. Vehicle and cooking small sources SOA appears important Biogenic source Enhanced in smoke plume OC Source Contribution (µg/m³) conc. (ng/m³) SOA/Other Vehicle Emissions Meat Cooking Biomass Combustion July 14-2 July July 28-Aug 3 Aug 4-1 Aug 1-16 Aug Aug 24-3 Aug 31-Sep 5 Pinic Acid Pinonic Acid Pinonaldehyde July 14-2 July July 28-Aug 3 Aug 4-1 Aug 1-16 Aug Aug 24-3 Aug 31-Sep 5 Engling et al (26) Atmos. Environ. 4,

17 Can we improve spatial and temporal resolution?

18 Anion exchange with electrochemical detection Filter Sample 2 O extraction no derivatization Carbohydrates separated on anion exchange column can resolve levoglucosan, mannosan, galactosan, glucose, similar to IC but different detection Water extraction Inject into IC Engling et al. (26) Atmos. Environ. 4, S299 S311

19 Levoglucosan measurement capabilities 4 Levoglucosan Calibration Pulsed amperometric detection MDL ~.2 µg/ml ~ 1 ng/m 3 in a 12 hr i-vol sample On-line measurement possible PILS Lab-on-a-chip Response y = x R 2 = c (ug/ml)

20 Yosemite daily levoglucosan 3 IC-PAD method makes daily levoglucosan measurement practical Estimated smoke contributions reach/exceed 1% on some days Need more source profiles for wildland fires Levoglucosan (ng/m³) /14/2 7/2/2 7/26/2 8/1/2 8/7/2 8/13/2 8/19/2 8/25/2 8/31/2 1 8 % of OC /15/2 7/21/2 7/27/2 8/2/2 8/8/2 8/14/2 8/2/2 8/26/2 9/1/2

21 Fresno wood smoke study Dec/Jan study Daily samples at 5 sites Levoglucosan, OC, EC analysis Evaluate spatial and temporal variability in wood smoke CSUF: Mixed Drummond: Industrial Clovis: Residential Pacific: Residential/Mixed First Street:Urban

22 Fresno wood smoke study Levoglucosan concentrations similar across city closely track OC for first 2/3 of study Wood smoke contributes on average 18% of PM 2.5 mass 41% of PM 2.5 OC Max contributions of 4% and 54% levoglucosan (µg m -3 ) /25 CSUF Clovis Drummond First St. Pacific OC 12/27 12/29 12/31 1/2 1/4 1/6 1/8 1/1 1/12 1/14 Collection Date OC (µg m -3 ) Gorin et al. (26) JAWMA

23 New source profiles

24 Source profiles Most published source profiles are for residential wood combustion Emissions from open burning can look very different µg C/µg OC Ponderosa Pine Levoglucosan Emissions Levoglucosan emissions smaller in open burning fireplace open controlled burn Schauer et al., 21; ays et al., 22; Oros and Simoneit, 21

25 The FLAME USDA Forest Service Fire Science Lab at Missoula Characterization of primary smoke emissions undreds of burns Fuel components and complexes NW, SW, and SE fuel emphasis Chemistry, optical properties, hygroscopicity Experiment Cottonwood Sage Tundra Duff Ponderosa Pine Needles

26 Comparison to Literature Values for Ponderosa Pine Branches (dead, large) Branches (dead, small) Branches (fresh, large) Branches (fresh, small) Needle Litter FLAME ,.27,.37,.33,.31 Needles (fresh).16 Complex.32,.16 Duff.27,.34 ays et al., 22 (burn enclosure) Schauer et al., 21 (residential fireplace) Oros and Simoneit, 21 (controlled fire) *all units µg C/µg C

27 FLAME levoglucosan emissions Average LG/OC ~3.2% Spread in ratios modest No clear pattern by fuel Number of Samples Levoglucosan/OC Ratio 6 8x1-2

28 Does levoglucosan also correlate with K+? With EC? No correlation with K+ Anti-correlated with EC? 2 needles or branches 2 Levoglucosan (µg C/m 3 ) Levoglucosan (µg C/m 3 ) Potassium (µg/m 3 ) EC (µg C/m 3 ) 15

29 Are there fuel type markers? Response (nc) Lodgepole pine Needle Duff Needles (fresh) Needle Litter Needles/Branches Tr (min)

30 Concluding remarks Biomass combustion important contributor to PM in urban and rural settings New technique makes routine measurement more practical. Currently being applied to LADCO study IMPROVE C isotope study filters On-line measurement tests Need better handle on 14 Source profiles 12 Flaming vs. smoldering? 1 8 AMS signatures 6 ow do source profiles depend on T, OC? 4 Do lab tests translate to real world fires? 2 Production of SOA in smoke plumes Temp (C) w/uffman and Jimenez % Org_low volatilized