PM Sampler Placement and Sampler Errors! Why should Regulatory and Agricultural Industries Care? Dr. Michael Buser USDA Agricultural Research Service Cotton Production and Processing Research Unit Lubbock, TX (806) 746-5353 x 104 – Office (806) 543-1432 – Cell mike.buser@ars.usda.gov
PM 10 Samplers – Theoretical Errors 0.012 100% 0.04 Mass of particles < 10 Ambient PM (MMD - 10 μ m; GSD 1.5) Ideal Environment μ m that are captured 0.010 Criteria Guidelines 0.035 EPA Performance by the pre-collector (Mass 1) 80% Cumulative Penetration Efficiency Penetration Curve 0.03 0.008 Mass 2 True Cut Mass Density 0.025 Mass Density 60% 0.006 Uniform Particle Size Distribution 0.02 PM captured by the pre-collector (Sampler Cutpoint - 10 μ m; Slope 1.5) Common Assumption: 40% 0.004 0.015 Samplers produce a "nominal" cut, because it is commonly assumed that Mass of the particles > Mass 1 = Mass 2. In other words, the 10 μ m that are NOT errors offset one another. 0.01 captured by the pre- 0.002 Mass 1 20% collector (Mass 2) The assumption is only valid when the PSD's are described by a uniform Note: Mass 1 = Mass 0.005 distribution and encompass a sufficient range of particle diameters. 0.000 0 5 10 15 20 25 30 0% 0 Particle Diameter ( μ m) 1 10 100 Particle Diameter ( μ m) 0.006 0.014 Urban Environment Rural Environment Note: Mass 1 = 0.65 Mass 2 Ambient PM (MMD - 20 μ m; GSD 1.5) 0.005 0.012 Ambient PM (Urban) (MMD - 5.7 μ m; GSD 2.25) 0.010 Mass 2 0.004 Mass Density Mass Density 0.008 0.003 PM captured by the pre-collector 0.006 (Sampler Cutpoint - 10 μ m; Slope 1.5) 0.002 0.004 Mass 2 PM captured by the pre-collector 0.001 (Sampler Cutpoint - 10 μ m; Slope 1.5) 0.002 Mass 1 Mass 1 Note: Mass 1 ≠ Mass 0.000 0.000 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Particle Diameter ( μ m) Particle Diameter ( μ m)
Theoretical Ratios of PM 10 Sampler to True Concentrations (PSD – GSD = 2.0) 1.8 Ratio range for a 5.7 μ m MMD PSD 0.92 < Ratio < 0.99 (a < Ratio < b) Acceptable PM 10 sampler measurement to meet PLC 138 < x < 149 μ g/m 3 (Ratio * 150 μ g/m 3 ) 1.6 Ratio range for a 10 μ m MMD PSD 0.95 < Ratio < 1.05 (c < Ratio < d) Acceptable PM 10 sampler measurement to meet PLC 142 < x < 158 μ g/m 3 (Ratio * 150 μ g/m 3 ) Sampler Concentration True Concentration 1.4 Ratio range for a 20 μ m MMD PSD f 1.05 < Ratio < 1.39 (e < Ratio < f) Acceptable PM 10 sampler measurement to meet PLC 158 < x < 209 μ g/m 3 (Ratio * 150 μ g/m 3 ) 1.2 d e b 1.0 a < ratio < b, c < ratio < d, and e < ratio < f are the acceptable ratio ranges for 5.7, 10 and 20 μ m particles, respectively based on the c interaction of the PM 10 sampler performance characteristics and a particle size distribution. 0.8 0 5 10 15 20 25 30 35 40 Regulated PM 10 property line MMD ( μ m) concentration (PLC) = 150 μ g/m 3 Cutpoint = 10.5 µm; Slope = 1.6 Cutpoint = 9.5 µm; Slope = 1.6 Cutpoint = 10.5 µm; Slope = 1.4 Cutpoint = 9.5 µm; Slope = 1.4
Theoretical Ratios of PM 10 Sampler to True Concentrations (PSD – GSD = 1.5) 5.8 Ratio range for a 5.7 μ m MMD PSD 0.87 < Ratio < 0.96 (a < Ratio < b) Acceptable PM 10 sampler measurement to meet PLC 131 < x < 144 μ g/m 3 (Ratio * 150 μ g/m 3 ) 4.8 Ratio range for a 10 μ m MMD PSD 0.92 < Ratio < 1.07 (c < Ratio < d) Acceptable PM 10 sampler measurement to meet PLC 138 < x < 161 μ g/m 3 (Ratio * 150 μ g/m 3 ) Sampler Concentration True Concentration 3.8 Ratio range for a 20 μ m MMD PSD 1.81 < Ratio < 3.43 (e < Ratio < f) Acceptable PM 10 sampler measurement to meet PLC f 271 < x < 514 μ g/m 3 (Ratio * 150 μ g/m 3 ) 2.8 e 1.8 a < ratio < b, c < ratio < d, and e < ratio < f are the acceptable ratio ranges for 5.7, 10 and 20 μ m particles, respectively based d b on the interaction of the PM 10 sampler performance characteristics and particle size distribution. c 0.8 a 0 5 10 15 20 25 30 35 40 Regulated PM 10 property line MMD ( μ m) concentration (PLC) = 150 μ g/m 3 Cutpoint = 10.5 µm; Slope = 1.6 Cutpoint = 9.5 µm; Slope = 1.6 Cutpoint = 10.5 µm; Slope = 1.4 Cutpoint = 9.5 µm; Slope = 1.4
Theoretical Ratios of PM 2.5 Sampler to True Concentrations (PSD – GSD = 1.5) 200 Ratio range for a 5.7 μ m MMD PSD a < ratio < b, c < ratio < d, and e < ratio < f are the acceptable ratio ranges for 5.7, 10 and 20 μ m particles, respectively 1.24 < Ratio < 2.96 (a < Ratio < b) f Acceptable PM 2.5 sampler measurement to meet PLC based on the interaction of the PM 2.5 sampler performance 81 < x < 193 μ g/m 3 (Ratio * 65 μ g/m 3 ) characteristics and particle size distribution. 160 Ratio range for a 10 μ m MMD PSD 2.85 < Ratio < 13.14 (c < Ratio < d) Acceptable PM 2.5 sampler measurement to meet PLC 185 < x < 854 μ g/m 3 (Ratio * 65 μ g/m 3 ) Sampler Concentration True Concentration 120 Ratio range for a 20 μ m MMD PSD 14.81 < Ratio < 183.5 (e < Ratio < f) Acceptable PM 2.5 sampler measurement to meet PLC 963 < x < 11,929 μ g/m 3 (Ratio * 65 μ g/m 3 ) 80 40 d e b c 0 a 0 5 10 15 20 25 30 35 40 Proposed PM 2.5 property line MMD ( μ m) concentration (PLC) = 65 μ g/m 3 Cutpoint = 2.7 µm; Slope = 1.33 Cutpoint = 2.3 µm; Slope = 1.27
PM 10 Sampler – Actual Errors 1600 Source MMD = 13.4 μ m MMD = 12.3 μ m Theoretical Errors - GSD = 1.94 GSD = 2.0 1400 Assuming the Sampler Performance Characteristics D 50 = 24.1 μ m Remain within the EPA defined tolerances Slope = 2.9 True PM 10 Concentration ( μ g/acm) 1200 1000 True PM 10 = Sampler PM 10 800 600 400 True PM 10 = 0.55 * Sampler PM 10 R 2 = 0.81 200 0 0 200 400 600 800 1000 1200 1400 1600 1800 PM 10 Sampler Concentration ( μ g/acm)
So What! Concentration ( μ g/m 3 ) MMD ( μ m) GSD TSP 1,207 13.4 2 PM 10 812 11.3 1.8 0.8 TSP Filter 347 - PSD Data Lognormal Fit (MMD = 11.8; GSD = 2.02) � Bottom Line! � Cutpoint = 24.1 μ m 0.6 Differential Volume (%) { compared to 10 μ m} 0.4 � Slope = 2.9 { compared to 1.5} 0.2 0 1 10 100 Particle Diameter ( μ m)
Errors Associated with PM Stack & Ambient Samplers Ambient Stack PM 10 Over- Source Sampling Rate Cotton Gin 181 % Cattle Feed Yard 185 % Almond Harvesting 139 % 350% In Field Measurement 300% Oversampling Rate (%) Theoretical (D50=10.5, Slp=1.6) 250% 200% 150% 100% 50% 0% 1 2 3 4 5 6 7 8 9 10 11 12 Run
Questions 1) Health based studies – are the PM data 1 used in the studies comparable? A. Are we comparing apples to apples? Plant A (M-201a) MMD = 3.7 μ m 0.8 GSD = 1.8 2) If I stand at the property line that PM 10 = 96% separates Plant A and B will Plant B’s PM 2.5 = 27% (higher PM 10 sampler based C= 54 mg/dscm concentration) emissions more negatively impact my health? 0.6 Volume (%) Plant B (M-201a) MMD = 12.9 μ m 3) If I’m evaluating regional PM air quality GSD = 1.7 PM 10 = 56% models using FRM PM sampler PM 2.5 = 1.3% concentrations, how good are my 0.4 C= 60 mg/dscm modeling results? A. Garbage in – garbage out 4) Are these plants being equally 0.2 regulated? 5) How will you answer the same questions for PM 2.5 ? 0 1 10 100 1) The PSD differences are greater Particle Diameter ( μ m)
Perspective
Characteristics of Various Types of Particulate Matter Particle Density MMD ( μ m) (g/cm 3 ) Source GSD Reference Urban Urban Dust 5.7 2.25 NR USEPA (1996a) Agricultural Rice 21.75 NR NR Plemons (1981) Rice 12.10 2.24 1.46 Parnell et al. (1986) Corn 19.57 NR NR Plemons (1981) Corn 13.70 NR NR Wade (1979) Corn 13.60 1.80 1.50 Parnell et al. (1986) Soybeans 25.17 NR NR Plemons (1981) Soybeans 30.00 NR NR Martin (1981) Soybeans 15.50 NR NR Wade (1979) Soybeans 14.80 1.87 1.69 Parnell et al. (1986) Wheat 32.97 NR NR Plemons (1981) Wheat 14.70 2.08 1.48 Parnell et al. (1986) Sorghum 36.92 NR NR Plemons (1981) Sorghum 15.70 2.16 1.43 Parnell et al. (1986) Cotton Gin (Combined Streams) 20 - 23 1.82 – 2.00 1.8 - 2.0 Wang (2000) Cotton Lint Fibers 12.94 2.25 NR Parnell and Adams (1979) Cattle Feedlot (Downwind) 14.2 2.25 1.71 Sweeten et al. (1989) Swine Finishing House (Aerial) 14.3 2.02 NR Barber et al. (1991) Swine Finishing House (Settled) 18.4 1.99 NR Barber et al. (1991) Swine Production Facility 17.97 NR NR Barber et al. (1991) Poultry Production Facility 24.0 – 26.7 1.6 NR Redwine and Lacey (2001) Typical Soil 25 2.0 2.5 Pargmann et al. (2000) NR – Data not reported in the reference.
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