Source Apportionme

PM2.5 at Houston Clinto

David W. Sullivan 

The University of Texas at Austin 

Center for Energy & Environmental Resear

Richard Tropp 

University of Nevada Reno

Desert Research Institute
PM2.5 Issues

• Clinton Drive, west end of Ship 

only site in Texas at risk of non

• 2004-2006 design value 15.4 μ

exceeds 15.0 NAAQS.

• Next highest DV in HGB:13 μg

• Various methods show “soil” to 

significant factor in why this site max.
Methods of Data Ana

• Analyze PM2.5 = f( rain, wind speed

• Analyze PM2.5 = f( time, weekday, s• Analyze PM10 & PM10/PM2.5 by win

• Use Hysplit

1 trajectories to assess t

• Use previous research results to de

factors. 

• Apply Positive Matrix Factorization 

1. Draxler, R.R. and Rolph, G.D., 2003. HYSPLIT (HYbrid Single-Particle LagranModel access via NOAA ARL READY Website (http://www.arl.noaa.gov/ready/hResources Laboratory, Silver Spring, MD. Rolph, G.D., 2003. Real-time Environmental Applications and Display sYstem (R(http://www.arl.noaa.gov/ready/hysplit4.html). NOAA Air Resources Laboratory, 
Major Features of Major Features of 

Atmospheric Particle Mass Dis

Atmospheric Particle Mass Dis

02468

10

0.001 0.01 0.1 1 

Particle Aerodynamic Diameter (μm)

Relative Mass Concentration

Accumulation Co

PM 1

PM 2.5

Geo

Materi

Se

Sulfate, Nitrate, 

Ammonium, 

Organic Carbon, 

Elemental Carbon, 

Heavy Metals, Fine 

Geological

Condensed 

Organic 

Carbon or 

Sulfuric Acid 

Vapors, Clean 

Environment

Ultrafine

Condensation 

Mode

Droplet 

Mode

PM 0.1

Nucleation

Fresh High 

Temperature 

Emissions, 

Organic 

Carbon, 

Sulfuric Acid, 

Metal Vapors
Data

• Clinton PM2.5 FRM mass, hourly T

• Clinton PM2.5 special speciation fo

– Quartz-filter: EC, OC, – Teflon-filter: ions, elements

• Clinton PM10 HiVol filter mass

• PM2.5 FRM and Speciation Networ

from other HGB sites

• PM2.5 Speciation Network sample c• Clinton wind speed resultant, wind 

resultant, and precipitation data.
Clinton and enviro
Clinton PM2.5 and mete

• Look at effects of rain, wind dir

wind speed.

• Compare PM2.5 and PM10 direc
PM2.5 and rain
PM2.5 and wind dire

• TEOM PM2.5

concentration by 10 deg. wind direction bin 2002-2007

• Relatively weak 

directionality, lowest concentrations to the north μg/m3
PM10 and wind direc

• 24-hour 

filter samples w hourly winds

• Clinton 

shows directionality to SW

Westhollow De

Aldine 

μg/m3 μg/m3

μg/m3 μg/m3
0°= north, 90°= east, 180°= south, 270°= 

% of PM2.5 > 15μg/m

3 from each 

wind direction in 2005, 2006 at Clint

0.0%1.0%2.0%3.0%4.0%5.0%6.0%7.0%8.0%9.0%

10.0%

0 30 60 90 120 150 180 210 240 2
Case study
Case Study - trans
PM2.5 and wind sp

• Regress 

hourly PM2.5 on wind speed by 30-deg. wind direction bin

• Slope 

negative all but S & SW

Dd

Directions 0-164, 226-360 deg

μg/m3 μg/m3
Meteorological evidence supp

• Higher PM2.5 after rain from dri

dust

• Strong directionality for PM10 (c

material in PMcoarse

)

• Positive association with wind s

dislodges surface soil.
Use speciation from past 

• As speciated data were collect

– Source profiles selected from EP

database for comparison

– Reconstruction formulas from pu

used to calculate factors:
Speciation data ana
Speciation Analys

• Inventory of data validated to 

Period Sample types 1/4/05 – 4/7/06 ions, elements (Teflon4/17/06 – 8/4/06 ions, elements (Teflon5/27/06 – 8/4/06 EC/OC (Quartz) 8/6/06 – 12/31/06 ions, elements (Teflon8/6/06 – 12/31/06 EC/OC (Quartz) Combined 5/27/06 – 12/31/06 EC/OC, ions, elements 

Teflon filters by XRF for elements and IC for ionsQuartz filters by thermal optical analysis for EC/OCFRM R&P 2025 sequential samplers
Tropp et al.’s (2006) Texas sp

• Soil = 1.89 * Al + 2.14 * Si + 1.40 

* Ca + 1.43 * Fe

• Ammonium sulfate = 1.38 * SO4= 

• Ammonium nitrate = 1.29 * NO3-

• Salt = 1.65 * Cl• Trace elements = sum of XRF 

species – (Al, Si, Ca, Fe, S, Cl, Na ) 

• OC = 1.4 * OCTTC 

• EC = ECTTC

• Other = the 

μg/m

3 from Teflon 

filter minus seven constituents above.

Al = AluminuSi = Silicon Ca = Calcium Fe = iron Cl = Chlorine 

Example of PM2.5 concentration fac

June 21, 2005 Reconstructed Species Comparison

05

101520253035

Aldine Channelview Bayland Park East Clinton 

ug/m3
Composite PM2.5 factor
Soil PM2.5 agrees w directions for “excess PM2.5” an

The data are from 24-hour samples on 30 “average”days and on 45 high PM2.5 days.
Aldine 2001-2005Channelview 2001Bayland 2002-2005

East 2001-2006

Deer Park 2001-2005

Clinton 20
Positive matrix factor

• Given multivariate data and co

uncertainties, EPA PMF 1.1 es

factors.

• User selects desired number o

and must interpret output.

• Results at Clinton w 63 62 sam

2006 similar to results on longeseries at other Houston area spsites.
Positive matrix factor

• Solve matrix eq. X = G F + E 

– X is n 

× m matrix of samples 

× sp

– G is n 

× p matrix of contribution o

sample 

– F is p 

× m matrix of fixed source 

– E is residual

• Min Q = sumI(sum

J(eIJ

2 / sIJ

2))

• Generally, good soln has Q* = • This model n = 62, m = 17, Qta
Results

• Q* = 1091 (vs 1054)• 7 factors• However, reconstruction of tota

from the factor contributions haresidual.

• Hendler, 2006 has similar resu• Buzcu, et al. 2003 have differe














End comparison suggests need m

Compare Reconstruct to Actual

05

10152025303540

0 5 10 15 20 25 

ug/m3

ug/m3
Compare Hous. East (H

Factor Houston East ClinSulfate-rich secondary aerosol 

Sept. – Oct. fall

Nitrate-rich aerosol Nov. – Mar. winMotor vehicles Aug. – Jan. fallSea salt Mar., May-Jun. spri

Soil/crustal matter Jul. – Aug. spriIndustrial combustion Year-around sumBiomass burning May Not “Calcium” Not found Yea
Conclusion

• Soil-like material provides som

add-on at Clinton.

• Soil and dry bulk material samp

been taken for analysis and sodevelopment.

• Additional projects to assess tr

Mex.-CenAm smoke and to assregional trends apportionment 
Photos of dusty nearb
At Clinton Gate – Facing 
Valero Asphalt

Immediately to the East of t
At Gate – Facing West t

PTRA / A&L Loading 
At Monitor – Across from 

PTRA and A&L Loading 
A&L Trucking/Ranger S

Use of Emulsified Asph
Emulsified Asphalt...co

(tracking from outside roa
Crushed Concrete Mate