IMPROVE Carbon Analysis - Colorado State...

IMPROVE Carbon Analysis

Judith C. Chow ([email protected]) Xiaoliang Wang Dana L. Trimble

L.-W. Antony Chen John G. Watson

Desert Research Institute, Reno, NV

Presented at

the IMPROVE Steering Committee Meeting

Incline Village, NV

October 23, 2012

Objectives

• Report status and improvements of IMPROVE carbon analyses

• Update progress on next-generation carbon analyzer (DRI Model 20XX)

Carbon Laboratory Operations (July 2011 to June 2012)

• Received ~1,900 samples per month (between

800 – 3292)

• Maintained 24 hours per day/6-7 days per week operation with seven staff

• Analyzed ~21,000 IMPROVE samples per year (800 to 3,394 per month)

• Averaged ~3,000 samples per month in the queue (1,000 to 4,455)

• Participated in UC Davis Artifact Study (~560

samples for December 2011, January and August 2012)

IMPROVE Carbon Analysis following

the IMPROVE_Aa Protocol (July 2011 to June 2012)

Sampling Period Samples Received

Analysis Completion Date

7/1/11-12/31/11 12,794 April 2012

1/1/12-6/30/12 10,850 October 2012

a Chow et al. (2007) JAWMA

Regular oxygen performance tests show values within the

100 ppm tolerance (Tested every six months)

0

10

20

30

40

50

60

70

80

90

100

CA #6 CA #7 CA #8 CA #9 CA #10 CA #11 CA #12 CA #13 CA #16 CA #19

Tra

ce

Ox

yg

en

Co

nc

en

tra

tio

n (

pp

m O

2)

Instrument ID

Aug 2011 Feb 2012 Aug 2012

OC1 at 140

C in 100% Helium atmosphere

Low OC and EC levels found on pre-fired

quartz-fiber filters (Acceptance testing, August 2011-July 2012)

0.0

0.5

1.0

1.5

2.0

Q539

8A

Q66

01B

Q66

10B

Q66

19B

Q66

28B

Q66

37B

Q66

46B

Q66

55B

Q66

64B

Q66

73B

Q66

82B

Q66

92A

Q67

01A

Q67

10A

Q67

19A

Q67

28B

Q67

37B

Q67

46B

Q67

56B

Q67

65B

Q67

74B

Q67

83B

Q679

2B

Q68

01B

Q68

10B

Q68

19B

Q68

29A

Q68

38A

Q68

47B

Q68

56B

Q68

66B

Q68

75B

Q68

84B

Q68

93B

Q69

02B

Q69

14A

Q69

24A

Q69

33B

Q69

42B

Q69

51B

Q69

60B

Q69

70B

Q69

79B

Q69

88B

Ca

rbo

n M

ea

su

rem

en

t (µ

g C

/cm

2)

Acceptance Quartz Filter ID

OCTRC ECTRC

Acceptable OC (1.5 µgC/cm²) Acceptable EC (0.5 µgC/cm²)

Average OC (0.24±0.22 µgC/cm²) Average EC (0.005±0.024 µgC/cm²

March 2012

Daily instrument auto-calibrationa is

within ±5% tolerance

-10

-8

-6

-4

-2

0

2

4

6

8

10

7/1

/2011

8/6

/2011

9/1

2/2

011

10/1

8/2

011

11/2

4/2

011

12/3

0/2

011

2/5

/2012

3/1

2/2

012

4/1

8/2

012

5/2

4/2

012

6/3

0/2

012

Perc

en

tag

e D

iffe

ren

ce

of

Au

to-C

ali

bra

tio

n

Pea

k R

es

po

ns

e (

%)

Date of Auto-calibration Analysis

CA#6 CA#7 CA#8 CA#9 CA#10

CA#11 CA#12 CA#13 CA#16 CA#19

a With He, He/O2 and CH4

Quarterly standard calibration is within ±5%

tolerance (Sucrose; thrice per week)

16.0

16.5

17.0

17.5

18.0

18.5

19.0

19.5

20.07

/1/2

01

1

8/6

/20

11

9/1

2/2

01

1

10

/18

/20

11

11

/24

/20

11

12

/30

/20

11

2/5

/20

12

3/1

2/2

01

2

4/1

8/2

01

2

5/2

4/2

01

2

6/3

0/2

01

2

To

tal

Ca

rbo

n M

ea

su

rem

en

t (µ

g C

)

Date of Sucrose Analysis

CA#6 CA#7CA#8 CA#9CA#10 CA#11CA#12 CA#13CA#16 CA#19Upper Acceptable Limit (18.9 µg C) Lower Acceptable Limit (17.1 µg C)

Improvements in Carbon Analyzer (DRI Model 2001)

• Updated oven relay (with active air cooling) to reduce electrical resistance, ensure sufficient heat dissipation, and minimize outages

• Installed a new coupler (between light pipe to optical fiber) to ensure stability and reduce laser drift (<1.5%)

Worldwide Helium Shortage Mitigation Strategy

• Current helium (He) consumption is 2,500 L/day with an annual cost exceeding $10,000

• Plans to reduce He consumption by 50% (Add new

circuit board with valves)

– Stop He-3 venting through methanator during analysis (50

mL/min)

– Toggle make-up He valves (i.e., He-3, He-2, and CH4)

• Eventually replace He with another non-oxidizing gas (e.g., nitrogen or argon)

Helium Tanks

Gas Regulator

Implement EUSAAR-IIa Protocol in

DRI Model 2001 Temperature Residence Timeb

OC in 100% He IMPROVE_A EUSAAR-II EUSAAR-II

OC1 140 °C 200 °C 120 sec

OC2 280 °C 300 °C 150 sec

OC3 480 °C 450 °C 180 sec

OC4 580 °C 650 °C 180 sec

EC in 98% He/2% O2

EC0 -- 500 °C 120 sec

EC1 580 °C 550 °C 120 sec

EC2 740 °C 700 °C 70 sec

EC3 840 °C 850 °C 80 sec

a European Supersites for Atmospheric Aerosol Research protocol b IMPROVE_A residence times are predicated on peak and return-to-baseline

and range from 120 to 580 seconds.

Revised carbon analysis SOP to reflect

improvements (Number 2-216r3, October 22, 2012)

• Revised daily calibration schedule

• Updated QA/QC activities

• Enhanced troubleshooting guide

Chow et al., ABC, 2011

Sunday Monday Tuesday Wednesday Thursday Friday Saturday

Morning (Startup; 7 a.m.)

System blank, lab blank, Autocalib

Lab blank, sucrose

Lab blank, Autocalib, KHP

Lab blank, sucrose

Lab blank, Autocalib, KHP

Lab blank, sucrose

Lab blank, Autocalib

Evening (7 p.m.)

CO2 injection

Autocalib CO2 injection



Efforts in Carbon Research • Examined data trendsa between EC and filter

reflectance (EC–τR) to resolve questions about consistency after instrument upgrade (2005) with IMPROVE_A protocola

• Obtained NSF grant ($390,000 from Environmental Chemical

Science Program) to characterize source and chemical structures of brown carbon and compounds in thermal fractions (integrates Model 2001 with soft

photoionization TOF-MS)

• Conducted feasibility experiments for next generation DRI Model 20XX (Enhanced optical [λ=400–900 nm]

and elemental detection [C, H, N, S, O, and m/z spectra])

• Found changes in filter mass that may be related to organic vapor adsorption

aChen et al., 2012 AMT

Consistent Decreasing Trends in EC and

Reflectance (2000–2009)

Similar downward trends at 65 sites with average rates (relative

to the 2000–2004 baseline medians) of 4.5%/yr for EC and 4.1%/yr

for τR.

Chen et al., 2012 AMT

EC-τR Relationship shows minor changes for

most IMPROVE sites

EC+ (after 2005) vs. EC− (before

2005) relationships derived from robust regression analysis through τR

measurements show changes within

10% except for low-

loading samples (

20%).

Wemianche Wilderness

Brigantine National Wildlife Refuge

Hance Camp at Grand Canyon National Park

Corr

esp

on

din

g E

C+ b

y S

ite

(µ

g/c

m3)

10th to 90th Percentile EC- by Site (µg/cm2)

Washington, DC

Alaska

Integrated Model 2001 DRI carbon analyzer with

Photoionization Time-of-Flight/Mass Spectrometer (PI-TOF/MS; U. of Rostock, Germany)

Grabowski et al. (2012), ABC

y-scale x 0.25 !

y-scale x 0.25 !

y-scale x 1

OC I

OC II

OC III

IP

Sn

S0 REMPI Zimmermann, 2011

Mass spectra of

thermal carbon

fractions from Model

2001 with Resonance

Enhanced Multi-

Photon Ionization-

Time-of-Flight/Mass

Spectrometry (REMPI-

TOF/MS)

Potential configuration for next generation

thermal/optical carbon analyzer (DRI Model 20XX)

Flow Control

NetworkCHNS Reactor

(MnO2)

C→CO2, H→H2O,

N→NOx/N2, S→SO2

NDIR CO2

Detector

Carrier/Reaction

Gases

98

% H

e,2

% O

2

He

He

, C

H4

He

, O

2, N

O, S

O2

Calibration

Gases

Oven

Filter Loading

Push Rod

UV-VIS-NIR

Light Source

(λ=400-900 nm)

Optical

Spectrometer

(Reflectance)

Optical

Spectrometer

(Transmittance)

Optical

Fibers

Filter

Filter

Holder

Thermocouple

Heated Fused

Silica Capillary

Unoxidized species

Mass

Spectrometer

Vent

Four-Way

Solenoid Valve

Flow

Splitter

Outputs:

Reflectance/

Transmittance

Spectra

O

Mass Spectra

C, H, N, S

O Reactor

(C/Ni)

O→CO

Oxidation

Oven

(CuO)

CO→CO2

Oxidation

Oven

(CuO)

CO→CO2

Oxidation

Reactor

C→CO2

FIDMethanator

CO2→CH4

From

Oven

DRI Model 2001 Carbon Analyzer

C

DRI Model 2001

Carbon Analyzer

Outputs:

Use annular oven to measure key

elements and mass spectra Septum for

calibration gas

Outlet for un-oxidized fragments

Dual catalytic ovens

Reflectance Arm

Transmittance Arm

Sample Cross

• Allow the evolved gases to be analyzed with or without pre-catalytic conversion.

• Two ovens contain MnO2 or Ni/C catalyst for C, H, N, S, or O analysis

MnO2 Ni/C

MS signals are linear with C, H, N, and S quantities

in various calibration chemicals

y = 0.0694xR² = 0.998

0

2

4

6

8

10

12

0 50 100 150 200

MS

m/z

= 4

4 (

CO

2+)

Sig

na

l

Mass of C (µg)

Sulfanilamide

L-Cystine

CO2

CH4

C:

y = 0.2329xR² = 0.993

0

1

2

3

4

0 5 10 15 20

MS

m/z

= 1

8 (

H2O

+)

Sig

na

l

Mass of H (µg)

Sulfanilamide

L-Cystine

(NH4)2SO4

NH4NO3

CH4

H:

y = 0.0121xR² = 0.960

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80

MS

m/z

= 3

0 (

NO

+)

Sig

nal

Mass of N (µg)

Sulfaniamide

L-Cystine

(NH4)2SO4

NH4NO3

N:

y = 0.0423xR² = 0.996

0

1

2

3

0 20 40 60 80

MS

m/z

= 6

4 (

SO

2+)

Sig

nal

Mass of S (µg)

Sulfanilamide

L-Cystine

(NH4)2SO4

S:

Sulfanilamide: C6H8N2O2S; L-Cystine: C6H12N2O4S2

Use reverse flow for O analysis to minimize

baseline drift (Reduce holding times by 45 minutes)

y = 0.75xR² = 0.92

0

10

20

30

40

50

0 20 40 60

Ex

pe

cte

d O

(µ

g)

NDIR Signal (mV)

Sucrose

KHP

Levoglucosan

O:

Non-dispersive infrared detector

Time (min)

20 40 60 80

Ion

Sig

nal

(a.u

.)

0.0

2.0e+4

4.0e+4

6.0e+4

8.0e+4

1.0e+5

1.2e+5

8.0e+5

1.0e+6

1.2e+6

Oven

Tem

pera

ture

(°C

)

0

200

400

600

800

1000

m/z=44 (CO2

+)

m/z=18 (H2O+) m/z=30 (NO

+)

m/z=64 (SO2

+)

CalibrationCH

4 Injection

Temperature

100% He 98% He / 2% O2

140°C

280°C

480°C

580°C

740°C

840°C

(a)

m/z=28 (CO+, N

2

+)

time vs Temp

Time vs m/z18

Time vs m/z28

Time vs m/z30

Time vs m/z64

Time (min)

20 40 60 80

ND

IR S

ign

al

(mV

)

40

60

80

100

400500

Oven

Tem

pera

ture

(°C

)

0

200

400

600

800

1000

140°C

280°C480°C

580°C

CalibrationO

2 Injection

NDIR

Temperature

100% He(b)

y = 0.926x - 0.104

R² = 0.989

0

1

2

3

4

5

6

0 1 2 3 4 5 6

Car

bo

n M

ass

by

Elem

en

tal A

nal

yzer

(µg)

Carbon Mass by Carbon Analyzer (µg)

EC1

OC3

OC2OC4

OC1

EC2EC3

1:1 Line

Quantify C, H, N, S, and O using the IMPROVE_A

protocol

Thermogram of Fresno ambient aerosol sample for (a) CHNS, and (b) O following the IMPROVE_A protocol.

Comparison of carbon fractions measured by elemental analyzer and DRI Model 2001

MS

Sig

nal (a

.u.)

Mass

spectrometry

produced

elemental

concentrations

comparable with

other detectors

IC-CD: Ion chromatography with conductivity detector FID: Flame ionization detector

Elemental composition varies between

summer and winter (Fresno, California)

Abundant (NH4)2SO4 in summer (Decompose at 200‒400

C; OC2 at 280

C in 100% Helium) (EC/TC=0.23)

Abundant NH4NO3 in winter (Dissociation starts at room temperature; OC1 at 140

C in 100% Helium) (EC/TC=0.28)

Source profiles vary between gasoline and

diesel samples for carbon fractions

Most carbon is in EC2; S is low due to low-S fuel. (EC/TC=0.62)

Increased C in OC and EC1 compared to diesel soot. (EC/TC=0.73)

Unoxidized mass spectra show different patterns

between gasoline and diesel exhaust samples

0.0

2.0e+4

4.0e+4

6.0e+4

0.0

2.0e+4

4.0e+4

6.0e+4

0.0

6.0e+4

1.2e+5

1.8e+5

2.4e+5

Ion m/z

50 100 150 200 250 300 350 400 450

Ion

co

un

t (a

.u.)

0.0

6.0e+5

1.2e+6

1.8e+6

2.4e+6

Gasoline Engine Exhaust

OC1: 140 °C

OC2: 280 °C

OC3: 480 °C

OC4: 580 °C

207

219233

252

57

71 9781

111

149125

341281

0

1e+5

2e+5

3e+5

4e+5

0

2e+5

4e+5

6e+5

0

1e+5

2e+5

3e+5

4e+5

5e+5

Ion m/z

50 100 150 200 250 300 350 400 450

Ion

co

un

t (a

.u.)

0

6e+5

1e+6

2e+6

2e+6

3e+6

Diesel Engine Exhaust

OC1: 140 °C

OC2: 280 °C

OC3: 480 °C

OC4: 580 °C

207 233 251

429

73

95 147281

355

341

325267

219

415399

327

221207

55

Experimental Configuration Using Xenon Lamp

and Spectrophotometers

Sample filter

Quartz light pipe

Xenon lamp Reflectance Spectrophotometer (200-1100 nm)

Transmittance Spectrophotometer (200-1100 nm)

Oven

0.00

0.05

0.10

0.15

0.20

0.25

350 400 450 500 550 600 650Re

fle

cta

nc

e A

tte

nu

ati

on

(-)

Wavelength (nm)

1

2

3

4

5

6

7

8

9

10

0

100

200

300

400

500

600

700

800

900

0 500 1000 1500 2000 2500 3000

No

rma

lize

d L

as

er

Refl

ec

nta

nce

,Tra

ns

mit

tan

ce,

FID

Sig

na

l

Sa

mp

le O

ve

n T

em

pe

ratu

re ( C

)

Anaylsis Time (sec)

TempR (633 nm)T (633 nm)FID

Spectral reflectance distinguishes native and charred light-

absorbing carbon in wood smoke

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

350 400 450 500 550 600 650

Re

fle

cta

nc

e A

tte

nu

ati

on

(-)

Wavelength (nm)

Spectral reflectance reveals brown carbon absorption for humic acid

33 DRI publications using IMPROVE protocol since 2011 meeting

• Bell, S.W.; Hansell, R.A.; Chow, J.C.; Tsay, S.C.; Wang, S.H.; Ji, Q.; Li, C.; Watson, J.G.; Khlystov, A. (2012). Constraining aerosol optical models using ground-based, collocated particle size and mass measurements in variable air mass regimes during the 7-SEAS/Dongsha experiment. Atmos. Environ., online.

• Cao, J.J.; Li, H.; Chow, J.C.; Watson, J.G.; Lee, S.C.; Rong, B.; Dong, J.G.; Ho, K.F. (2011). Chemical composition of indoor and outdoor atmospheric particles at Emperor Qin's terra-cotta museum, Xi'an, China. AAQR, 11(1):70-79. http://aaqr.org/VOL11_No1_February2011/8_AAQR-10-10-OA-0088_70-79.pdf.

• Cao, J.J.; Chow, J.C.; Tao, J.; Lee, S.C.; Watson, J.G.; Ho, K.F.; Wang, G.H.; Zhu, C.S.; Han, Y.M. (2011). Stable carbon isotopes in aerosols from Chinese cities: Influence of fossil fuels. Atmos. Environ., 45(6):1359-1363.

• Cao, J.J.; Shen, Z.X.; Chow, J.C.; Lee, S.C.; Watson, J.G.; Tie, X.X.; Ho, K.F.; Wang, G.H.; Han, Y.M. (2012). Winter and summer PM2.5 chemical compositions in 14 Chinese cities. J. Air Waste Manage. Assoc., 62(10):1214-1226. DOI: 10.1080/10962247.2012.701193. http://www.tandfonline.com/doi/pdf/10.1080/10962247.2012.7011933 .


(continued)

• Cao, J.J.; Wang, Q.Y.; Chow, J.C.; Watson, J.G.; Tie, X.X.; Shen, Z.X.; An, Z.S. (2012). Impacts of aerosol compositions on visibility impairment in Xi'an, China. Atmos. Environ., 59:559-566.

• Cao, J.J.; Huang, H.; Lee, S.C.; Chow, J.C.; Zou, C.W.; Ho, K.F.; Watson, J.G. (2012). Indoor/outdoor relationships for organic and elemental carbon in PM2.5 at residential homes in Guangzhou, China. AAQR, 12(5):902-910. http://aaqr.org/VOL12_No5_October2012/18_AAQR-12-02-OA-0026_902-910.pdf.

• Chen, L.-W.A.; Watson, J.G.; Chow, J.C.; DuBois, D.W.; Herschberger, L. (2011). PM2.5 source apportionment: Reconciling receptor models for U.S. non-urban and urban long-term networks. J. Air Waste Manage. Assoc., 61(11):1204-1217.

• Chen, L.-W.A.; Robles, J.A.; Wang, X.; Chow, J.C.; Watson, J.G. (2011). Thermal pretreatment for online measurement of black carbon. Presented at 10th International Conference on Carbonaceous Particles in the Atmosphere (ICCPA), Vienna, Austria, 6/26-29/2011.

• Chen, L.-W.A.; Chow, J.C.; Watson, J.G.; Schichtel, B.A. (2012). Consistency of long-term elemental carbon trends from thermal and optical measurements in the IMPROVE network. Atmospheric Measurement Techniques Discussion, 5:2329-2338. http://www.atmos-meas-tech.net/5/2329/2012/amt-5-2329-2012.pdf.

• Chen, L.-W.A.; Watson, J.G.; Chow, J.C.; Green, M.C.; Inouye, D.; Dick, K. (2012). Wintertime particulate pollution episodes in an urban valley of the western U.S.: A case study. Atmos. Chem. Phys. Discuss., 12(1):36. http://www.atmos-chem-phys-discuss.net/12/15801/2012/acpd-12-15801-2012.pdf.

• Chen, L.-W.A.; Tropp, R.J.; Li, W.-W.; Zhu, D.Z.; Chow, J.C.; Watson, J.G.; Zielinska, B. (2012). Aerosol and air toxics exposure in El Paso, Texas: A pilot study. AAQR, 12(2):169-189. http://aaqr.org/VOL12_No2_April2012/3_AAQR-11-10-OA-0169_169-179.pdf.

• Cheng, Y.; Zou, S.C.; Lee, S.C.; Chow, J.C.; Ho, K.F.; Watson, J.G.; Han, Y.M.; Zhang, R.J.; Zhang F.; Yau, P.S.; Huang, Y.; Bai, Y.; Wu, W.J. (2011). Characteristics and source apportionment of PM1 emissions at a roadside station. J. Hazard. Mat., 195:82-91.

• Chow, J.C.; Watson, J.G.; Robles, J.; Wang, X.L.; Chen, L.-W.A.; Trimble, D.L.; Kohl, S.D.; Tropp, R.J.; Fung, K.K. (2011). Quality assurance and quality control for thermal/optical analysis of aerosol samples for organic and elemental carbon. Anal. Bioanal. Chem., 401(10):3141-3152. DOI 10.1007/s00216-011-5103-3.

• Chow, J.C.; Watson, J.G.; Chen, L.-W.A.; Lowenthal, D.H.; Motallebi, N. (2011). PM2.5 source profiles for black and organic carbon emission inventories. Atmos. Environ., 45(31):5407-5414.

• Chow, J.C.; Watson, J.G. (2012). Chemical analyses of particle filter deposits. In Aerosols Handbook : Measurement, Dosimetry, and Health Effects, 2; Ruzer, L., Harley, N. H., Eds.; CRC Press/Taylor & Francis: New York, NY, 179-204.

• Cortez-Lugo, M.; Escamilla-Nunez, C.; Barraza-Villarreal, A.; Texcalc-Sangrador, J.L.; Chow, J.C.; Watson, J.G.; Hernandez-Cadena, L.; Romieu, I. (2012). Association between light absorption measurements of PM2.5 and distance from heavy traffic roads in the Mexico City metropolitan area. Salud publica de Mexico, submitted

• Grabowsky, J.; Streibel, T.; Sklorz, M.; Chow, J.C.; Mamakos, A.; Zimmermann, R. (2011). Hyphenation of a carbon analyzer to photo-1 ionization mass spectrometry to unravel the organic composition of particulate matter on a molecular level. Anal. Bioanal. Chem., 401(10):3153-3164.

• Green, M.C.; Chow, J.C.; Chang, M.C.O.; Chen, L.W.A.; Kuhns, H.D.; Etyemezian, V.R. (2012). Source apportionment of atmospheric particulate carbon in Las Vegas, Nevada, USA. Particuology, in press.

• Gyawali, M.; Arnott, W.P.; Zaveri, R.A.; Song, C.; Moosmüller, H.; Liu, L.; Mischchenko, M.L.; Chen, L.-W.A.; Green, M.C.; Watson, J.G.; Chow, J.C. (2012). Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols. Atmos. Chem. Phys., 12:2587-2601. http://www.atmos-chem-phys.net/12/2587/2012/acp-12-2587-2012.pdf.

• Han, Y.M.; Cao, J.J.; Yan, B.Z.; Kenna, T.C.; Jin, Z.D.; Cheng, Y.; Chow, J.C.; An, Z.S. (2011). Comparison of elemental carbon in lake sediments measured by three different methods and 150-year pollution history in eastern China. Environ. Sci. Technol., 45(12):5287-5293.


(continued)

• Ho, S.S.H.; Chow, J.C.; Watson, J.G.; Ng, L.P.T.; Kwok, Y.; Ho, K.F.; Cao, J.J. (2011). Precautions for in-injection port thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) applied to aerosol filter samples. Atmos. Environ., 45(7):1491-1496.

• Hu, T.F.; Cao, J.J.; Ho, K.F.; An, Z.S.; Lee, S.; Chow, J.C.; Watson, J.G.; Li, H. (2011). Winter and summer characteristics of airborne particles Inside Emperor Qin's Terra-Cotta Museum, China: A study by scanning electron microscopy-energy dispersive x-ray spectrometry. J. Air Waste Manage. Assoc., 61(9):914-922.

• McDonald, J.D.; White, R.K.; Holmes, T.; Mauderly, J.L.; Zielinska, B.; Chow, J.C. (2012). Simulated downwind coal combustion emissions for laboratory inhalation exposure atmospheres. Inhal. Toxicol., 24(5):310-319.

• Pope, C.A., III; Ayala, A.; Bailar, J.C.; Bell, M.; Boyle, K.J.; Brandt, S.; Bui, L.; Corbett, J.J.; Fernandez, I.J.; Frey, H.C.; Fuglestvedt, J.; Gerking, S.; Helble, J.J.; Jacobson, M.Z.; Levy, J.; Menon, S.; Poirot, R.L.; Russell, A.G.; Walsh, M.; Watson, J.G. (2011). Review of the draft report to Congress on black carbon. prepared by U.S. Environmental Protection Agency, Washington,DC, http://yosemite.epa.gov/sab/sabproduct.nsf/fedrgstr_activites/38059D3EA6FE3A19852578EA004A7469/$File/EPA-COUNCIL-11-002-unsigned.pdf.

• Sahu, M.; Hu, S.; Ryan, P.H.; LeMasters, G.; Grinshpun, S.A.; Chow, J.C.; Biswas, P. (2011). Chemical compositions and source identification of PM2.5 aerosols for estimation of a diesel source surrogate. Sci. Total Environ., 409(13):2642-2651. http://www.sciencedirect.com/science/article/pii/S0048969711002853.

• Soto-Garcia, L.L.; Andreae, M.O.; Andreae, T.W.; Artaxo, P.; Maenhaut, W.; Kirchstetter, T.; Novakov, T.; Chow, J.C.; Mayol-Bracero, O.L. (2011). Evaluation of the carbon content of aerosols from the burning of biomass in the Brazilian Amazon using thermal, optical and thermal-optical analysis methods. Atmos. Chem. Phys., 11(9):4425-4444.


(continued)

• Wang, X.L.; Watson, J.G.; Chow, J.C.; Kohl, S.D.; Chen, L.-W.A.; Sodeman, D.A.; Legge, A.H.; Percy, K.E. (2012). Measurement of real-world stack emissions with a dilution sampling system. In Alberta Oil Sands: Energy, Industry, and the Environment, Percy, K. E., Ed.; Elsevier Press: Amsterdam, The Netherlands, in press.

• Wang, X.L.; Watson, J.G.; Chow, J.C.; Gronstal, S.; Kohl, S.D. (2012). An efficient multipollutant system for measuring real-world emissions from stationary and mobile sources. AAQR, 12(1):145-160. http://aaqr.org/VOL12_No2_April2012/1_AAQR-11-11-OA-0187_145-160.pdf.

• Watson, J.G.; Chow, J.C. (2011). Ambient aerosol sampling. In Aerosol Measurement: Principles, Techniques and Applications, Third Edition, 3; Kulkarni, P., Baron, P. A., Willeke, K., Eds.; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 591-614.

• Watson, J.G.; Chow, J.C.; Wang, X.L.; Lowenthal, D.H.; Kohl, S.D.; Gronstal, S. (2011). Real-world emissions from non-road mining trucks. Report Number 010109-123109; prepared by Desert Research Institute, Reno, NV, for Ft. McMurray, AB, Canada, Wood Buffalo Environmental Association.

• Watson, J.G.; Chow, J.C.; Wang, X.L.; Kohl, S.D.; Gronstal, S. (2011). Winter stack emissions measured with a dilution sampling system. prepared by Desert Research Institute, Reno, NV, for Ft. McMurray, AB, Canada, Wood Buffalo Environmental Association.

• Watson, J.G.; Chow, J.C.; Lowenthal, D.H.; Chen, L.; Wang, X.L. (2012). Reformulation of PM2.5 mass reconstruction assumptions for the San Joaquin Valley. prepared by Desert Research Institute, Reno, NV, for San Joaquin Valley Unified Air Pollution Control District, Fresno, CA.

• Zhou, J.M.; Cao, J.J.; Zhang, R.J.; Chow, J.C.; Watson, J.G. (2012). Carbonaceous and ionic components of atmospheric fine particles in Beijing and their impact on atmospheric visibility. AAQR, 12(4):492-502. http://aaqr.org/VOL12_No4_August2012/4_AAQR-11-11-OA-0218_492-502.pdf.


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Canada and China have adopted

IMPROVE_A for their long-term networks

Future Activities

• Retrofit new valves and circuit boards to reduce helium consumption on carbon analyzers.

• Evaluate comparability and differences between IMPROVE_A and EUSAAR-II protocols.

• Participate in European efforts for round-robin carbon intercomparison and standard reference material (SRM) development.

• Develop algorithm to convert reflectance/transmission signal to absorption and compare Angstrom Absorption Exponent to quantify OC, brown carbon, and EC.

• Integrate C, H, N, S, with O analysis.

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