Simulating diurnal changes of speciated particulate matter in Atlanta, Georgia using

CMAQ

Yongtao Hu, Jaemeen Baek, Bo Yan, Rodney Weber,

Sangil Lee, Evan Cobb, Amy Sullivan, Armistead G. Russell

School of Civil and Environmental Engineering and School of Earth and Atmospheric Sciences, Georgia Institute of Technology

CMAS conference, October 18th, 2006

Acknowledgements: Eric S. Edgerton and John JansenARA and Southern Company

Background

Speciated particulate matter monitored at two sites in Georgia Tech's campus, 500m away from each other

Measurements at neighboring sites HYW and ROF

• Frequency: twice per day of 12-hr average compositions of PM2.5 for daytime (10am~10pm) and nighttime (10pm~10am).

• Items: ions, EC/OC, organic compounds and metals.

• Periods: Jun. 15~18, 2006 and Jan. 19~26, 2006.

0

5

10

15

20

25

ug

/m3

NH4

SO4

NO3

EC

OC

• Findings: Compare two sites: ROF is cleaner;

SO4 and NH4: no significant difference; NO3: ROF is higher, but both very low; EC and OC: HYW is significantly higher.

Compare day and night: Higher

percentage of OC at night; Higher percentage of SO4 during day.

Other PM2.5 composition monitors in Atlanta Met

1.3-km Grid

- 56 km -

- 56 km-

• SEARCH stations: JST and YRK, hourly composition of PM2.5, as well as daily 24-hr averages

• ASACA stations: FTM, TUC, SDK, YGP, daily 24-hr average composition of PM2.5

• STN site: South De Kalb (same location as SDK), every third day 24-hr average composition of PM2.5

Super Site Jefferson Street

0

10

20

30

40

50

60

Time EST

PM

2.5

ug/m

3

Sampling frequency

STN site 130890002 South De Kalb

0

10

20

30

40

50

60

Time EST

PM

2.5

ug/m

3

Can CMAQ capture the observed gradient of the EC/OC concentration at the two closely neighboring sites?

Can CMAQ capture the observed diurnal changes of PM2.5 and its components?

Questions:

Objectives of this work

• Simulating PM2.5 speciation using CMAQ at very fine scale.

• Characterize emissions from freeway.

• Compare fine scale CMAQ results to observations using detailed speciation of organics and metals (just have EC/OC and ions for now). Next to freeway, nearby (500m), 2km away, within the region.

• Mutual calibration with receptor modeling results.

• Reconcile differences: Improve emission characterization, emissions distributions, dispersion, etc.

CMAQ v4.5 simulation • Four nesting domains down to 1.3-km resolution.

• Thirteen vertical layers, first layer ~18 meters.

• Simulating summer episode currently: June 12-20, 2005.

• SAPRC99 mechanism plus aero4 module.

• MM5 and SMOKE provide meteorology and emission rate fields.

• OSU land surface model plus 4DDA (only for 36-km and 12-km grids) used in MM5.

• VISTAS 2002 emissions inventory projected to 2005, CEM data used for EGU sources.

Brute force sensitivity simulations

sensitivity fields = air quality fields basecase - air quality fields reduced case

Domainwide 100% reduction NOx VOC SO2 NH3 EC OC EGU X X non-EGU X X mobile X X X X X non-road X X X X biogenic X biomass burning X X livestock X fugitive dust X other area sources X X

20 sensitivity runs

Modeling Domains

36-km

1.3-km

4-km

12-km

Basecase 1.3-km Grid Emissions

NOx

POAPEC

CO

Simulated Spatial Distributions on 1.3-km Grid (basecase)

O3

ECOCNO3

NH4SO4

First Concern:

Is 1.3-km grid performance worse than coarse grid?

Surface Wind Speed Surface Wind Direction Surface Air Temperature Surface Humidity Grid Bias

(m s-1) RMSE (m s-1)

Bias (deg.)

Gross Error (deg.)

Bias (K)

RMSE (K)

Bias (g kg-1)

Gross Error (g kg-1)

12-km 0.63 1.83 2.64 30.67 0.03 2.58 -1.05 1.49 4-km 0.98 1.61 3.26 34.40 0.27 2.39 -0.77 1.33 1.3-km 0.24 1.60 5.32 34.71 0.41 2.27 -0.46 1.21

MM5 Performance: 1.3-km grid vs. other resolutions

Compare with TDL hourly surface observations

Grid Species Uni t Pai rs# MOC MNB MNE FB FE O3 ppmv 46337 0.0526 -9.62 22.27 -15.50 26.35

8hrO3 ppmv 41687 0.0508 -10.36 19.55 -14.61 22.61 PM25 ug/m3 1835 10.8419 17.18 49.80 -1.05 40.69

36-km

PM25h ug/m3 40040 12.3868 34.99 91.37 -19.23 61.75 O3 ppmv 9362 0.0560 -8.00 17.18 -11.07 19.27

8hrO3 ppmv 8922 0.0537 -7.33 14.58 -9.36 15.95 PM25 ug/m3 272 16.0681 -33.36 39.15 -46.20 49.11

12-km

PM25h ug/m3 6321 17.0702 -21.76 59.59 -51.82 63.55 O3 ppmv 2227 0.0585 -13.89 18.45 -17.43 21.60 8hrO3 ppmv 2183 0.0555 -12.88 16.08 -15.25 18.22 PM25 ug/m3 65 19.1095 -45.26 48.29 -64.22 66.25

4-km

PM25h ug/m3 2114 19.4284 -36.40 54.70 -63.53 71.41 O3 ppmv 475 0.0623 -12.58 16.82 -15.40 19.36

8hrO3 ppmv 486 0.0584 -10.85 15.11 -12.86 16.83 PM25 ug/m3 26 17.7108 -45.74 46.23 -63.66 64.14

1.3-km

PM25h ug/m3 711 18.7498 -37.23 61.12 -69.81 76.95

Compare with Network measurements from: AIRNOW, STN, CASTNet (O3 only), IMPROVE, SEARCH and ASACA

CMAQ Performance: 1.3-km grid vs. other resolution

Further Concern:

Is PM2.5 performance becoming worse when compared to measurements in higher

temporal resolution?

1.3-km grid PM2.5 performanceCompare with 24-, 12- and 1-hr measurements, respectively

Species Unit Pairs# MOC MNB MNE FB FE PM25-24hr ug/m3 26 17.7108 -45.74 46.23 -63.66 64.14 PSO4-24hr ug/m3 22 4.2197 2.09 51.28 -13.93 49.88 PNO3-24hr ug/m3 22 0.2953 -80.42 80.42 -141.61 141.61 PNH4-24hr ug/m3 22 1.3740 -9.46 31.40 -16.86 33.91 PEC-24hr ug/m3 22 0.8247 60.05 102.80 5.32 62.42 POC-24hr ug/m3 22 5.2166 -70.94 70.94 -112.30 112.30 PM25-12hr ug/m3 13 18.9408 -42.45 45.45 -59.08 61.82 PSO4-12hr ug/m3 14 4.4507 7.05 46.94 -6.74 43.02 PNO3-12hr ug/m3 14 0.7007 53.85 195.09 -109.75 156.21 PNH4-12hr ug/m3 14 1.7800 -27.93 28.08 -34.66 34.81 PEC-12hr ug/m3 14 2.5100 -46.40 55.39 -77.67 84.79 POC-12hr ug/m3 14 6.8407 -80.08 80.08 -136.56 136.56 PM25-1hr ug/m3 711 18.7498 -37.23 61.12 -69.81 76.95 PSO4h-1hr ug/m3 100 4.9546 13.14 77.54 -30.25 61.21 PNO3h-1hr ug/m3 85 0.4529 -95.12 95.12 -183.09 183.09 PNH4h-1hr ug/m3 87 1.6118 -20.47 32.73 -33.18 43.64 PECh-1hr ug/m3 120 1.2989 -40.38 45.89 -58.75 63.17 POCh-1hr ug/m3 119 4.7756 -71.81 71.82 -118.98 118.98

HWY

0

5

10

15

20

25

30

6/15/05 10:00 6/15/05 22:00 6/16/05 10:00 6/16/05 22:00 6/17/05 10:00 6/17/05 22:00 6/18/05 10:00

Time EST

ug/m

3PM25 OBS

PM25 SIM

PSO4 OBS

PSO4 SIM

PNH4 OBS

PNH4 SIM

PNO3 OBS

PNO3 SIM

POC OBS

POC SIM

PEC OBS

PEC SIM

ROF

0

5

10

15

20

25

30

6/15/05 10:00 6/15/05 22:00 6/16/05 10:00 6/16/05 22:00 6/17/05 10:00 6/17/05 22:00 6/18/05 10:00

Time EST

ug/m

3

PM25 OBS

PM25 SIM

PSO4 OBS

PSO4 SIM

PNH4 OBS

PNH4 SIM

PNO3 OBS

PNO3 SIM

POC OBS

POC SIM

PEC OBS

PEC SIM

Limited EC/OC gradient was captured between HYW and ROF HIGHWAY

ROOF

EC sensitivity at HYW

-20%

0%

20%

40%

60%

80%

100%

6/13/0510:00

6/13/0522:00

6/14/0510:00

6/14/0522:00

6/15/0510:00

6/15/0522:00

6/16/0510:00

6/16/0522:00

6/17/0510:00

6/17/0522:00

6/18/0510:00

6/18/0522:00

6/19/0510:00

6/19/0522:00

Time EST

PEC_OAVOCPEC_OAPOAPEC_NVOCPEC_NPOAPEC_NPECPEC_NNOXPEC_NEGUSO2PEC_NEGUNOXPEC_MVOCPEC_MPOAPEC_MPECPEC_MNOXPEC_MNH3PEC_LNH3PEC_FPOAPEC_FPECPEC_EGUSO2PEC_EGUNOXPEC_DPOAPEC_BVOC

EC sensitivity at ROF

-20%

0%

20%

40%

60%

80%

100%

6/13/0510:00

6/13/0522:00

6/14/0510:00

6/14/0522:00

6/15/0510:00

6/15/0522:00

6/16/0510:00

6/16/0522:00

6/17/0510:00

6/17/0522:00

6/18/0510:00

6/18/0522:00

6/19/0510:00

6/19/0522:00

Time at EST

PEC_OAVOCPEC_OAPOAPEC_NVOCPEC_NPOAPEC_NPECPEC_NNOXPEC_NEGUSO2PEC_NEGUNOXPEC_MVOCPEC_MPOAPEC_MPECPEC_MNOXPEC_MNH3PEC_LNH3PEC_FPOAPEC_FPECPEC_EGUSO2PEC_EGUNOXPEC_DPOAPEC_BVOC

EC Sensitivity results show a higher contribution from traffic emissions at HIWAY

HIGHWAY

ROOF

Non-road EC

Non-road EC

Mobile EC

Mobile EC

JST

0.01

0.1

1

10

100

Time EST

log u

g/m

3

PM25 OBS

PM25 SIM

PSO4 OBS

PSO4 SIM

PNH4 OBS

PNH4 SIM

PNO3 OBS

PNO3 SIM

POC OBS

POC SIM

PEC OBS

PEC SIM

YRK

0.01

0.1

1

10

100

Time EST

log u

g/m

3

PM25 OBS

PM25 SIM

PSO4 OBS

PSO4 SIM

PNH4 OBS

PNH4 SIM

PNO3 OBS

PNO3 SIM

POC OBS

POC SIM

PEC OBS

PEC SIM

Diurnal Changes: captured OK for SO4, NH4 and EC, not OK for OC

Jefferson Street (urban)

Yorkville (rural)

OC performance: diurnal change JST

0123456789

10

Time

PO

C (ug/m

3)

OBS

SIM

YRK

0

2

4

6

8

10

12

Time

PO

C (

ug

/m3)

OBS

SIM

Jefferson Street (urban)

Yorkville (rural)

OC sensitivity at JST

-20%

0%

20%

40%

60%

80%

100%

6/13/057:00

6/13/0519:00

6/14/057:00

6/14/0519:00

6/15/057:00

6/15/0519:00

6/16/057:00

6/16/0519:00

6/17/057:00

6/17/0519:00

6/18/057:00

6/18/0519:00

6/19/057:00

6/19/0519:00

6/20/057:00

Time EST

POC_OAVOCPOC_OAPOAPOC_NVOCPOC_NPOAPOC_NPECPOC_NNOXPOC_NEGUSO2POC_NEGUNOXPOC_MVOCPOC_MPOAPOC_MPECPOC_MNOXPOC_MNH3POC_LNH3POC_FPOAPOC_FPECPOC_EGUSO2POC_EGUNOXPOC_DPOAPOC_BVOC

OC sensitivity at YRK

-20%

0%

20%

40%

60%

80%

100%

6/12/0519:00

6/13/057:00

6/13/0519:00

6/14/057:00

6/14/0519:00

6/15/057:00

6/15/0519:00

6/16/057:00

6/16/0519:00

6/17/057:00

6/17/0519:00

6/18/057:00

6/18/0519:00

6/19/057:00

6/19/0519:00

6/20/057:00

Time EST

POC_OAVOCPOC_OAPOAPOC_NVOCPOC_NPOAPOC_NPECPOC_NNOXPOC_NEGUSO2POC_NEGUNOXPOC_MVOCPOC_MPOAPOC_MPECPOC_MNOXPOC_MNH3POC_LNH3POC_FPOAPOC_FPECPOC_EGUSO2POC_EGUNOXPOC_DPOAPOC_BVOC

OC Sensitivity: does it make sense?

Jefferson Street (urban)

Yorkville (rural)

BVOC

OAPOA

NPOA

MPOAFPOADPOA

OAVOC

OAVOCOAPOANPOAMPOAMNOXFPOADPOA

BVOC

ES&T ROOF

0

2

4

6

8

10

Time EST

ug

/m3

POC OBS POCPA SIM POCS SIM POCS OBS

Estimate Secondary OC from OC measurements

When EC was well reproducedAssume Pri OCobs = Pri OCsim,then, we have SOAobs = OCobs - PriOCsim

YRK

0

2

4

6

8

10

Time EST

ug

/m3

POCPA SIM POCS SIM POCS OBS POC OBS

ROOF

Yorkville

Secondary OC was not captured by CMAQ, both mechanism and precursor emissions need improvements.

Summary

• Performance of 1.3-km grid is as good as other resolutions. This is encouraging.

• Limited EC/OC gradient was captured at neighboring sites. Link-base VMT is necessary to allocate the mobile emissions more accurately.

• Utilize modeled primary OC to split SOA from observed OC. With uncertainty.

• OC diurnal change was not captured. SOA prediction needs to be improved. Problems are from both mechanism and precursor emissions.

species unit number moc mnb mne fb fe PM25-24hr ug/m3 65 19.1095 -45.26 48.29 -64.22 66.25 PSO4-24hr ug/m3 35 4.9072 -8.48 46.59 -24.14 50.45 PNO3-24hr ug/m3 35 0.3057 -64.77 91.54 -131.97 146.43 PNH4-24hr ug/m3 35 1.4988 -13.91 27.23 -20.85 31.69 PEC-24hr ug/m3 35 0.8224 53.17 99.16 1.61 66.20 POC-24hr ug/m3 35 6.2997 -68.88 68.88 -108.53 108.53 PM25-12hr ug/m3 13 18.9408 -45.12 45.12 -61.08 61.08 PSO4-12hr ug/m3 14 4.4507 -0.67 34.59 -7.68 34.40 PNO3-12hr ug/m3 14 0.7007 -1.82 142.24 -115.68 155.95 PNH4-12hr ug/m3 14 1.7800 -28.54 28.54 -34.40 34.40 PEC-12hr ug/m3 14 2.5100 -46.55 58.06 -80.65 89.47 POC-12hr ug/m3 14 6.8407 -79.42 79.42 -134.82 134.82 PM25-1hr ug/m3 2114 19.4284 -36.40 54.70 -63.53 71.41 PSO4-1hr ug/m3 229 4.8857 -2.20 58.30 -29.46 54.26 PNO3-1hr ug/m3 229 0.3549 -79.05 90.31 -156.37 162.79 PNH4-1hr ug/m3 230 1.5436 -15.27 35.99 -26.89 43.79 PEC-1hr ug/m3 288 0.9969 -38.97 47.68 -60.38 67.36 POC-1hr ug/m3 284 4.3190 -52.61 70.00 -97.37 108.89 PTC-1hr ug/m3 284 5.3101 -50.61 64.99 -89.35 99.45

4-km grid PM2.5 performanceCompare with 24-, 12- and 1-hr measurements, respectively

EC performance JST

0

1

2

3

4

5

6

7

Time

PE

C (ug/m

3)

OBS

SIM

YRK

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Time

PE

C (ug/m

3)

OBS

SIM

SO4 performance JST

0

5

10

15

20

25

30

35

40

45

Time

PS

O4

(ug

/m3)

OBS

SIM

YRK

0

2

4

6

8

10

12

14

16

Time

PS

O4 (ug/m

3)

OBS

SIM