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Particulate Measurement Impacts of Different Size Selective Inlets. Prepared by Bryan Lambeth, P.E. Texas Commission on Environmental Quality for presentation at the 2006 National Air Quality Conference. Size Selective Inlets Used on Partisol and TEOM Particulate Monitors.
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Particulate Measurement Impactsof Different Size Selective Inlets Prepared by Bryan Lambeth, P.E. Texas Commission on Environmental Quality for presentation at the 2006 National Air Quality Conference
Size Selective Inlets Used on Partisol and TEOM Particulate Monitors PM2.5 Sharp Cut Cyclone (SCC) PM10 Inlet PM2.5 WINS Inlet PM2.5 Very Sharp Cut Cyclone (VSCC) WINS = Well Impactor Ninety Six TEOM = Tapered Element Oscillating Mass
Collocated Measurement Comparisons • PM2.5 FRM WINS versus TEOM SCC unadjusted • PM2.5 FEM VSCC versus TEOM SCC unadjusted • PM2.5 FEM VSCC versus TEOM SCC adjusted • PM10 FEM Wedding hi-vol versus FEM TEOM FRM = Federal Reference Method FEM = Federal Equivalent Method
Selected Collocated PM2.5 Sites Lubbock C306 Dallas Hinton C401 El Paso Sun Metro C40 Houston Aldine C8
Scale in Miles Detailed Site Maps Hinton Sun Metro Aldine Lubbock
Dallas Hinton 481130069 PM2.5 WINS VSCC Before TEOM Adjustment
Dallas Hinton 481130069 PM2.5 VSCC After TEOM Adjustment Before TEOM Adjustment
Dallas Hinton 481130069 PM2.5 WINS Summer Winter Before TEOM Adjustment
Dallas Hinton 481130069 PM2.5 VSCC Summer Winter Before TEOM Adjustment
Dallas Hinton 481130069 PM2.5 VSCC Summer Winter After TEOM Adjustment
Houston Aldine 482010024 PM2.5 WINS VSCC Before TEOM Adjustment
Houston Aldine 482010024 PM2.5 VSCC After TEOM Adjustment Before TEOM Adjustment
Houston Aldine 482010024 PM2.5 WINS Summer Winter Before TEOM Adjustment
Houston Aldine 482010024 PM2.5 VSCC Summer Winter Before TEOM Adjustment
El Paso Sun Metro 481410053 PM2.5 WINS VSCC Before TEOM Adjustment
El Paso Sun Metro 481410053 PM2.5 VSCC After TEOM Adjustment Before TEOM Adjustment
El Paso Sun Metro 481410053 PM2.5 WINS Summer Winter Before TEOM Adjustment
El Paso Sun Metro 481410053 PM2.5 VSCC Summer Winter Before TEOM Adjustment
Lubbock 483030001 PM2.5 WINS VSCC Before TEOM Adjustment
Lubbock 483030001 PM2.5 WINS Summer Winter Before TEOM Adjustment
Lubbock 483030001 PM2.5 VSCC Summer Winter Before TEOM Adjustment
TEOM PM10 Inlet Problem • TEOM PM10 data shows large 20 to 40 percent high bias when compared to collocated Wedding hi-vol PM10 data • Supported by measurements from 3 collocated TEOM and hi-vol PM10 sites in Texas • TEOM PM10 dust storm filters viewed with a microscope showed numerous round particles 10 to 20 microns in size – indicating a TEOM inlet cut-point problem
PM10/coarse Inlet Problem • The TEOM PM10 inlet is the same inlet used on the monitor that is currently proposed as FRM for PM10 non-continuous monitoring for PMcoarse determination using a PM10-PM2.5 difference method • This inlet could lead to PMcoarse high bias in areas with significant mass loadings slightly above 10 microns (dust prone areas)
Solutions • Short-Term: Adjust slope and intercept on TEOM PM10 monitor to provide data that more closely matches Wedding hi-vol data • Proposed adjustment more important for sites with high dust levels, especially sites that do not need equivalency designation but need accurate AQI readings for public • Long-Term: Have vendor supply an inlet that has a sharper 10-micron cut point and has EPA equivalency rating
Collocated PM10 Site Locations Socorro C49 Laredo C44 Mission C43
Collocated PM10 Site Locations Laredo C44 Socorro C49 Mission C43
Site Year Hi-Vol TEOM Proposed Count Mission 2002 21.1 29.1 23.8 55 Laredo 2004 21.0 24.2 20.5 59 Socorro 2004 37.4 53.4 41.7 59 PM10 Annual Averages Concurrent Samples (mg/m3) TEOM– instrument slope 1.03 and intercept 3 (equivalent) Proposed – instrument slope 0.75 and intercept 5
Mission 2150043 PM10 Equivalent Adjustment Proposed Adjustment TEOM Slope 1.03 / Intercept 3 TEOM Slope 0.75 / Intercept 5
Laredo 484790016 PM10 Equivalent Adjustment Proposed Adjustment TEOM Slope 1.03 / Intercept 3 TEOM Slope 0.75 / Intercept 5
El Paso Socorro 481410057 PM10 Equivalent Adjustment Proposed Adjustment TEOM Slope 1.03 / Intercept 3 TEOM Slope 0.75 / Intercept 5
Web Links • TCEQ Air Quality Index Report:http://www.tceq.state.tx.us/cgi-bin/compliance/monops/psi_rptAQI shown on this report for high dust events may often be over-rated based on TEOM data • TCEQ Air Pollution Events:http://www.tceq.state.tx.us/compliance/monitoring/air/monops/sigevents06.htmlAQI level assigned in these analyses based on TEOM data for dust events may often be over-rated • TCEQ Today’s Air Quality Forecast:http://www.tceq.state.tx.us/compliance/monitoring/air/monops/forecast_today.htmlForecast development and verification is affected by inaccurate TEOM data – both PM10 for dust situations and PM2.5 for winter stagnation events