Utah Wintertime PM2.5 ModelingUtah Wintertime PM2.5 Modeling

Lance AveyUtah Division of Air Quality

http://www.airquality.utah.gov/

Ammonium Sulfate 9%

Organic Carbon 20% Ammonium Nitrate

58%

Other 5%

Elemental Carbon 5%

Dust 2%

PM2.5 Speciation

NOx + VOCs HNO3 (nitric acid)

HNO3 + NH3 NH4NO3 (particulate)

NAAQS for PM2.5

• EPA revised the NAAQS for PM2.5 in December of 2006

– 24-hr standard was lowered from 65 micrograms per cubic meter

(µg/m3) to 35 µg/m3

– Annual standard was retained at 15 µg/m3

– Retained the 24-hr standard for PM10 at 150 µg/m3

State Implementation Plan

• Basic Elements include:

– Modeled Attainment Demonstration (with chemistry)– Emissions Inventories– Emission Limits– Attainment Dates (2 – 7 years after SIP)

Retrospective Modeling

• Replicate the meteorological, emissions, and chemistry of past high PM2.5 episodes

• In the future, the same meteorology and chemistry will cause high PM2.5 episodes

• Future emissions will change – Population Growth, new technologies, cleaner vehicles

• Allows DAQ to evaluate how future changes in emissions (and control strategies) effect PM2.5

EmissionsPoint, Area, Mobile

• 36/12/4 km Horizontal Domain• 37 vertical layers

– 1st layer at ~ 12 meters

– 10 layers below 250 meters

– Initialization uses 12km-NAM Re-analysis

• Pleim-Xiu LSM & Surface Layer, ACM2 PBL• Simulations were ran in 5.5 day segments• Observational and Analysis Nudging

UDAQ Retrospective WRF

Modeling Domain

4km x 4km

WRF Output

2010 Jan 04 – Midnight Local Time

CMAQ Nitrate (ug/m3)

2010 Jan 04 – Midnight Local Time

Hawthorne

0

10

20

30

40

50

60

70

10-Jan 12-Jan 14-Jan 16-Jan 18-Jan 20-Jan 22-Jan

January 2007

24-h

r P

M2.

5 (u

g/m

3)

CMAQ Obs.

Hawthorne CMAQ PM2.5 Simulation Speciation

NO347%

NH416%

SO44%

OC12%

EC7%

OTHER14%

Hawthorne STN PM2.5 Observed Speciation

NO342%

NH416%

SO42%

OC21%

EC4%

OTHER15%

Hawthorne Monitor

Monitor Design Value (observations)

201

4 B

AU

Des

ign

Val

ue

201

9 B

AU

Des

ign

Val

ue

2014

Co

ntr

ol D

esig

n V

alu

e

201

9 C

on

tol D

esig

n V

alu

e

201

9 A

ttai

nm

ent

Des

ign

Val

ue

0

5

10

15

20

25

30

35

40

45

50

2008 2014 2019SLC-Ogden-Clearfield NAA Controling Monitor

PM

25 (

ug/m

3)

Future Year Modeling-Same Meteorology-Same Chemistry-Changes in Emissions