AIR QUALITY MODELING OF A TYPICAL WINTERTIME PM2.5 POLLUTION EVENT - - PowerPoint PPT Presentation

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AIR QUALITY MODELING OF A TYPICAL WINTERTIME PM2.5 POLLUTION EVENT - - PowerPoint PPT Presentation

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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

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SLIDE 1

NANCY DAHER, PH.D. & CHRISTOPHER PENNELL AIR QUALITY MODELER

AIR QUALITY MODELING OF A TYPICAL WINTERTIME PM2.5 POLLUTION EVENT IN CACHE VALLEY, UTAH: IMPLICATIONS FOR EMISSION CONTROL STRATEGIES

1

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SLIDE 2

OVERVIEW

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▸ Confined Topography ▸ Complex Terrain ▸ Strong Winter-time Inversions ▸ Exceedances of 24-hr PM2.5

NAAQS during Winter Inversions

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SLIDE 3

OVERVIEW

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Other 28% NH4 26% NO3 46% Other 40% NH4 19% NO3 41% Other 30% NH4 24% NO3 47%

▸ Confined Topography ▸ Complex Terrain ▸ Strong Winter-time Inversions ▸ Exceedances of 24-hr PM2.5

NAAQS during Winter Inversions

PM2.5 dominated by NH4NO3

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SLIDE 4

OVERVIEW

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Other 28% NH4 26% NO3 46% Other 40% NH4 19% NO3 41% Other 30% NH4 24% NO3 47%

▸ Ammonia ▸ HNO3 ▸ Ozone ▸ NOx ▸ Radical Sources (VOCs, ClNO2)

Complex Chemistry

Womack et al. , AQUARIUS 2019 workshop.

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SLIDE 5

OBJECTIVE

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▸ Model a Typical Wintertime

PM2.5 Inversion Event

▸ Implications for Control

Strategies

Cache Valley

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SLIDE 6

MODELING DOMAIN

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4 km (180 x 186) 1.33 km (201 x 90)

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SLIDE 7

MODEL CONFIGURATION

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4 km (180 x 186) 1.33 km (201 x 90)

▸ CAMxv6.3 ▸ 41 Vertical Layers ▸ Cb6r2h Chemistry

Mechanism

▸ ZHANG03 Dry Deposition

Scheme

▸ SMOKE3.6.5 Emissions

Processor

▸ WRF Meteorological

Processor + Custom Modifications

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SLIDE 8

MODELING EPISODE: WINTERTIME INVERSION

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  • 20

40 60 80 100

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 24−hr PM2.5 (ug/m3)

  • Measured

NAAQS

Logan Monitoring Station

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SLIDE 9

MODEL MODIFICATIONS: SURFACE SNOW ALBEDO

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Set Snow Cover Fraction to 0.88 for Urban Land Use

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SLIDE 10

MODEL MODIFICATIONS: OZONE DEPOSITION VELOCITY

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Hi ca (e ni me de cm OZ SN SN PE He Zeroed-out Ozone Deposition Velocity

Histogram of ozone deposition velocity calculations for the snow-covered period (early February) inclusive of both nighttime and daytime data. Mean and median ozone deposition velocity were -0.002 and 0.0 cm s-1

Helmig D. Et al. (2014). Final report: 2013 Uinta Basin Winter Ozone Study.

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SLIDE 11

MODEL MODIFICATIONS: AMMONIA INJECTION & SURFACE DEPOSITION

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County Saling Factor Cache 80 Box Elder 6 Weber 6 Davis 4 Salt Lake 4 Tooele 6 Utah 4

Increased Surface Resistance to Ammonia (“RScale = 1”)

2017 Utah Winter Fine Particulate Study.

  • 50

100

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

NH3 (ppb)

  • Modeled

Logan Monitoring Station

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SLIDE 12

RESULTS: 24-HR PM2.5

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  • 20

40 60 80 100

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 24−hr PM2.5 (ug/m3)

  • Measured

Modeled NAAQS

Logan Monitoring Station

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SLIDE 13
  • 20

40 60 80 100

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 24−hr PM2.5 (ug/m3)

  • Measured

Modeled NAAQS

Logan Monitoring Station

RESULTS: 24-HR PM2.5

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Mixing height Underestimated by 100 m in WRF

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SLIDE 14
  • 20

40 60 80 100

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 24−hr PM2.5 (ug/m3)

  • Measured

Modeled NAAQS

Logan Monitoring Station

RESULTS: 24-HR PM2.5

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SLIDE 15

NO3, 39.06, 52.9% NH4, 22.09, 29.9% SO4, 2.11, 2.9% OC, 5.32, 7.2% EC, 4.38, 5.9% Crustal material, 0.53, 0.7% Na, 0.06, 0.1% Other mass, 0.26, 0.4%

RESULTS: PM2.5 CHEMICAL SPECIATION

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Measured PM2.5 = 85.3 ug/m3 Modeled PM2.5 = 60.7 ug/m3

  • Jan. 07, Peak PM2.5 Day

NO3, 19.61, 32.3% NH4, 9.69, 16.0% SO4, 3.20, 5.3% OC, 8.57, 14.1% EC, 5.06, 8.3% Crustal material, 1.94, 3.2% Na, 0.13, 0.2% Other mass, 12.46, 20.5%

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SLIDE 16

RESULTS: CLNO2 ON A TYPICAL EXCEEDANCE DAY

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Logan Station Modeled

ClNO2 (pptv)

Peak at 450 pptv Peak at 1200 pptv Logan Station Measured

2017 Utah Winter Fine Particulate Study

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SLIDE 17

RESULTS: HCL ON A TYPICAL EXCEEDANCE DAY

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2017 Utah Winter Fine Particulate Study

< 0.25 ppbv 8 ppbv

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SLIDE 18

RESULTS: GASEOUS SPECIES - NOx

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  • ●
  • ●
  • 0.0

0.1 0.2

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

NOx (ppm)

  • Measured

Modeled

Logan Monitoring Station

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SLIDE 19

RESULTS: GASEOUS SPECIES - NOx

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  • ●
  • ●
  • 0.0

0.1 0.2

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

NOx (ppm)

  • Measured

Modeled

Logan Monitoring Station

Peak PM2.5 Days

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SLIDE 20

RESULTS: GASEOUS SPECIES - OZONE

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  • 0.00

0.01 0.02 0.03 0.04

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

O3 (ppm)

  • Measured

Modeled

Logan Monitoring Station

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SLIDE 21

RESULTS: GASEOUS SPECIES - OZONE

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  • 0.00

0.01 0.02 0.03 0.04

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

O3 (ppm)

  • Measured

Modeled

Logan Monitoring Station

Peak PM2.5 Days

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SLIDE 22

FINDINGS & IMPLICATIONS

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▸ Temporal Variation in PM2.5 Well Replicated ▸ Underestimation in Ammonium Nitrate ▸ Overestimation in NOx/Underestimation in O3 during Daytime Hours ▸ Potential Underestimation in Free Radical Sources ▸ Model Potentially Showing Disbenefits for Controlling NOx

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SLIDE 23

ACKNOWLEDGMENTS

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▸ Gail Tonnesen, EPA Region 8 ▸ Chris Emery, Ramboll ▸ Erik Crosman, West Texas A&M University

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SLIDE 24

THANK YOU

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SLIDE 25

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SLIDE 26

MODEL MODIFICATIONS: SNOW FRACTION

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CAMx Base Case WRF CAMx Modified Case

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SLIDE 27

RESULTS: GASEOUS SPECIES - NOx

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  • ●
  • ●
  • 0.0

0.1 0.2

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

NOx (ppm)

  • Measured

Modeled

Logan Monitoring Station

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SLIDE 28

RESULTS: GASEOUS SPECIES - OZONE

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  • 0.00

0.01 0.02 0.03 0.04

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

O3 (ppm)

  • Measured

Modeled

Logan Monitoring Station