� 1 AIR QUALITY MODELING OF A TYPICAL WINTERTIME PM2.5 POLLUTION EVENT IN CACHE VALLEY, UTAH: IMPLICATIONS FOR EMISSION CONTROL STRATEGIES NANCY DAHER, PH.D. & CHRISTOPHER PENNELL AIR QUALITY MODELER
� 2 OVERVIEW ▸ Confined Topography ▸ Complex Terrain ▸ Strong Winter-time Inversions ▸ Exceedances of 24-hr PM2.5 NAAQS during Winter Inversions
� 3 OVERVIEW Other 28% NO3 46% NH4 26% ▸ Confined Topography ▸ Complex Terrain ▸ Strong Winter-time Inversions ▸ Exceedances of 24-hr PM2.5 NAAQS during Winter Other NO3 Inversions 40% 41% NH4 19% PM2.5 dominated Other by NH4NO3 30% NO3 47% NH4 24%
� 4 OVERVIEW Other 28% NO3 46% NH4 26% Complex Chemistry ▸ Ammonia ▸ HNO3 ▸ Ozone ▸ NOx ▸ Radical Sources (VOCs, ClNO2) Other NO3 40% 41% NH4 19% Other 30% NO3 47% NH4 24% Womack et al. , AQUARIUS 2019 workshop.
� 5 OBJECTIVE Cache Valley ▸ Model a Typical Wintertime PM2.5 Inversion Event ▸ Implications for Control Strategies
� 6 MODELING DOMAIN 1.33 km (201 x 90) 4 km (180 x 186)
� 7 MODEL CONFIGURATION 4 km (180 x 186) ▸ CAMxv6.3 1.33 km (201 x 90) ▸ 41 Vertical Layers ▸ Cb6r2h Chemistry Mechanism ▸ ZHANG03 Dry Deposition Scheme ▸ SMOKE3.6.5 Emissions Processor ▸ WRF Meteorological Processor + Custom Modifications
MODELING EPISODE: WINTERTIME INVERSION 24 − hr PM2.5 (ug/m3) 100 20 40 60 80 0 ● 2011 − 01 − 01 ● 2011 − 01 − 02 Logan Monitoring Station ● 2011 − 01 − 03 ● ● 2011 − 01 − 04 Measured ● 2011 − 01 − 05 ● 2011 − 01 − 06 ● NAAQS ● 2011 − 01 − 07 ● 2011 − 01 − 08 ● 2011 − 01 − 09 ● 2011 − 01 − 10 � 8
� 9 MODEL MODIFICATIONS: SURFACE SNOW ALBEDO Set Snow Cover Fraction to 0.88 for Urban Land Use
� 10 MODEL MODIFICATIONS: OZONE DEPOSITION VELOCITY Zeroed-out Ozone Deposition Velocity Hi ca (e Histogram of ozone deposition velocity ni calculations for the snow-covered period me (early February) inclusive of both nighttime and daytime data. Mean and de median ozone cm deposition velocity were -0.002 and 0.0 cm s-1 OZ SN SN PE He Helmig D. Et al. (2014). Final report: 2013 Uinta Basin Winter Ozone Study.
� 11 MODEL MODIFICATIONS: AMMONIA INJECTION & SURFACE DEPOSITION Logan Monitoring Station Modeled ● ● Increased Surface ● ● ● ● ● ● ● ● NH3 (ppb) ● 100 ● Resistance to Ammonia ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● (“RScale = 1”) ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 50 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Saling ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● County ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Factor ● 2011 − 01 − 01 00:00:00 2011 − 01 − 02 00:00:00 2011 − 01 − 03 00:00:00 2011 − 01 − 04 00:00:00 2011 − 01 − 05 00:00:00 2011 − 01 − 06 00:00:00 2011 − 01 − 07 00:00:00 2011 − 01 − 08 00:00:00 2011 − 01 − 09 00:00:00 2011 − 01 − 10 00:00:00 2011 − 01 − 11 00:00:00 Cache 80 Box Elder 6 Weber 6 Davis 4 Salt Lake 4 Tooele 6 Utah 4 2017 Utah Winter Fine Particulate Study.
RESULTS: 24-HR PM2.5 24 − hr PM2.5 (ug/m3) 100 20 40 60 80 0 ● ● 2011 − 01 − 01 ● ● 2011 − 01 − 02 Logan Monitoring Station ● ● ● Measured 2011 − 01 − 03 ● ● 2011 − 01 − 04 ● ● ● 2011 − 01 − 05 Modeled ● ● 2011 − 01 − 06 ● ● 2011 − 01 − 07 ● NAAQS ● ● 2011 − 01 − 08 ● ● 2011 − 01 − 09 ● ● 2011 − 01 − 10 � 12
� 13 RESULTS: 24-HR PM2.5 Logan Monitoring Station Measured Modeled NAAQS ● ● ● 100 ● ● 24 − hr PM2.5 (ug/m3) 80 ● 60 ● Mixing height Underestimated ● by 100 m in WRF ● ● ● 40 ● ● ● ● ● ● ● ● 20 ● ● ● ● 0 2011 − 01 − 01 2011 − 01 − 02 2011 − 01 − 03 2011 − 01 − 04 2011 − 01 − 05 2011 − 01 − 06 2011 − 01 − 07 2011 − 01 − 08 2011 − 01 − 09 2011 − 01 − 10
RESULTS: 24-HR PM2.5 24 − hr PM2.5 (ug/m3) 100 20 40 60 80 0 ● ● 2011 − 01 − 01 ● ● 2011 − 01 − 02 Logan Monitoring Station ● ● ● Measured 2011 − 01 − 03 ● ● 2011 − 01 − 04 ● ● ● 2011 − 01 − 05 Modeled ● ● 2011 − 01 − 06 ● ● 2011 − 01 − 07 ● NAAQS ● ● 2011 − 01 − 08 ● ● 2011 − 01 − 09 ● ● 2011 − 01 − 10 � 14
� 15 RESULTS: PM2.5 CHEMICAL SPECIATION Measured Modeled PM2.5 = 85.3 ug/m3 PM2.5 = 60.7 ug/m3 Crustal Other mass, EC , 4.38, 5.9% material, 0.53, 0.26, 0.4% 0.7% OC, 5.32, 7.2% Na, 0.13, 0.2% Other mass, 12.46, 20.5% SO4, 2.11, 2.9% NO3, 19.61, Na, 0.06, 0.1% 32.3% Crustal material, 1.94, 3.2% NO3, 39.06, EC, 5.06, 8.3% 52.9% NH4, 22.09, 29.9% OC, 8.57, NH4, 9.69, 14.1% 16.0% SO4, 3.20, 5.3% Jan. 07, Peak PM2.5 Day
� 16 RESULTS: CLNO2 ON A TYPICAL EXCEEDANCE DAY Peak at 450 pptv Logan Station Modeled ClNO2 (pptv) Peak at 1200 pptv Logan Station Measured 2017 Utah Winter Fine Particulate Study
� 17 RESULTS: HCL ON A TYPICAL EXCEEDANCE DAY < 0.25 ppbv 8 ppbv 2017 Utah Winter Fine Particulate Study
� 18 RESULTS: GASEOUS SPECIES - NOx Logan Monitoring Station Measured Modeled ● ● ● ● ● ● ● NOx (ppm) ● ● 0.2 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 0.1 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 0.0 ● ● ● ● ● 2011 − 01 − 01 00:00:00 2011 − 01 − 02 00:00:00 2011 − 01 − 03 00:00:00 2011 − 01 − 04 00:00:00 2011 − 01 − 05 00:00:00 2011 − 01 − 06 00:00:00 2011 − 01 − 07 00:00:00 2011 − 01 − 08 00:00:00 2011 − 01 − 09 00:00:00 2011 − 01 − 10 00:00:00 2011 − 01 − 11 00:00:00
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