EC and BC Measurement during 

Characterization of Outdoor 

Wood-Fired Hydronic Heaters

Seung-Hyun Cho, William Linak, M. Ian 

Gilmour, Michael Hays, Brian Gullet
0 100 200 300 400 500 600 700

0

5

10

15

20

0

5

10

15

20

CO2 x Time = 4126 ppm. min

Cummulative Time (min)

6 AM - 6 PM



C

O2

Tra

c

e (%) at th

e

e

xit o

f th

e

B

oiler

CO2 x Time = 4023 ppm. min 6 PM - 6 AM

Similarity in the 

values, the 

number of damper 

openings, and the 

period of opening.

Wood is being consumed over time and 

max. CO2 drops accordingly. Consumption 

rate (slope) is about the same day or night. 

Similar trend in PM mass emissions also 

seen.

CO2 Comparison Between Two Consecutive 

12-hour Periods
Methane/Non-Methane HC Concentration Evolution 

After Initial Fuel Charge, Diluted

3/25/09 9:33 PM3/26/09 1:04 AM3/26/09 4:34 AM3/26/09 8:04 AM

3/26/09 11:35 AM

3/26/09 3:05 PM

0

50

100

150

200

250

300

350

400

450

500

M

eth

a

n

e

a

n

d

Oth

er T

H

C

C

o

n

c

e

ntratio

n (p

p

m)

Time (EDT)

 Methane

 Non-Methane THC
CO Concentration Evolution over Time, 

Diluted

3/25/09 9:33 PM3/26/09 1:04 AM3/26/09 4:41 AM3/26/09 8:11 AM

3/26/09 11:42 AM

3/26/09 3:12 PM

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

C

O

C

o

n

c

e

ntratio

n (p

p

m)

Time (EDT)

Animal studies 

conducted at low

emission 

(smoldering) 

condition

Active burning
Boiler

Models

Classic

(CL 5036)

E-Classic 

(2300)

Advanced Climate 

Technologies, LLC

Alternative Fuel 

Boilers (EBW-200)

Fuel type Red Oak Red Oak Wood Pellet Red Oak

Analyses/

Sample 

collection 

in full 

combustio

n cycle

• PM size distribution

• PM mass

• EC and OC 

(Thermal-OpticalTransmittance)

• SVOCs and VOCs

• CO2, CO, CH4, HC, 

NOx, etc.

• PM size distribution

• PM mass

• EC and OC 

(Thermal-OpticalTransmittance)

• SVOCs and VOCs

• CO2, CO, CH4, HC, 

NOx, etc.

• PM size distribution

• PM mass

• EC and OC 

(Thermal-OpticalTransmittance)

• SVOCs and VOCs

• CO2, CO, CH4, HC, 

NOx, etc.

• PM size distribution

• PM mass

• EC and OC 

(Thermal-OpticalTransmittance)

• SVOCs and VOCs

• CO2, CO, CH4, HC, 

NOx, etc.

Animal 

studies

April 7th-9th, 2009 May 19th-21st, 2009 June 16th-18th, 2009 No Animal Study

Analyses/

Sample 

collection 

during 

animal 

studies

• PM size and mass 

(<2mg/m3; PMfiltered; air control)

• Black Carbon 

(Aethalometer)

• EC and OC

(Thermal-OpticalTransmittance)

• Inorganic elements 

(XRF and ATOF-MS)

• CO, NOx, SO2

• PM size and mass 

(<2mg/m3; PMfiltered; air control)

• Black Carbon 

(Aethalometer)

• EC and OC

(Thermal-OpticalTransmittance)

• Inorganic elements 

(XRF and ATOF-MS)

• CO, NOx, SO2

• PM size and mass 

(<2mg/m3; PMfiltered; air control)

• Black Carbon 

(Aethalometer)

• EC and OC

(Thermal-OpticalTransmittance)

• Inorganic elements 

(XRF and ATOF-MS)

• CO, NOx, SO2

• PM size distribution

• Black Carbon 

(Aethalometer)

• EC and OC

(Thermal-OpticalTransmittance)

• Inorganic elements 

(XRF)

Comparison of Hydronic Heaters
Wood smoke drawn from an 

animal inhalation chamber.

Smoke divided between the Aethalometer (BC) and filter samples (EC).
CL 5036 (1st boiler) 

UV (organic) > BC

High CO

Black Carbon Measurement (Aethalometer)

During Full Cycle Study

Aethalometer Mar25,2009 (Red Oak)

0.0E+00

2.0E+05

4.0E+05

6.0E+05

8.0E+05

1.0E+06

1.2E+06

1.4E+06

1.6E+06

1.8E+06

9:099:299:49

10:0910:2910:4911:0911:2911:4912:0912:4213:0213:2213:4214:0214:2214:4215:0215:2215:4216:0216:2216:4217:02

n

g/m

3

BC (ng/m3)

UV data (ng/m3)
Aethalometer May 12,2009 (Red Oak)

0.0E+00

2.0E+05

4.0E+05

6.0E+05

8.0E+05

1.0E+06

1.2E+06

1.4E+06

1.6E+06

1.8E+06

17:55 18:15 18:55 19:15 19:35 19:55 20:15 20:35 20:55 21:15

n

g/m

3

BC (ng/m3)

UV data (ng/m3)

E-classic 2300 (2nd boiler) 

UV (organic) > BC

Black Carbon Measurement (Aethalometer)

During Full Cycle Study
Aethalometer Jun 11,2009 

(Wood Pellet; normal operation-no animal)

0.0E+00

2.0E+05

4.0E+05

6.0E+05

8.0E+05

1.0E+06

1.2E+06

1.4E+06

1.6E+06

1.8E+06

11:27 11:47 12:07 12:27 12:47 13:07 13:27 13:47 14:07 14:27

n

g/m

3

BC (ng/m3)

UV data (ng/m3)

ACT Pellet (3rd boiler)

UV (organic) ≤ BC

Frequent changes in combustion condition for temperature maintenance 

Black Carbon Measurement (Aethalometer)

During Full Cycle Study
Smoke EC/TC

0

0.1

0.2

0.3

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1

CL 5036 (Apr 09) 

Boiler #1

E-classic 2300 (May 09)

Boiler #2

ACT Pellet (Jun 09) 

Boiler #3

Ratio of Elemental Carbon to Total Carbon

During Animal Studies

(Thermal-Optical-Transmittance; NIOSH 5040 method)
HH 5036 (Red Oak; 04/07-04/09)

y = 0.879x - 2.1605

R

2

 = 0.6014

0.0

20.0

40.0

60.0

80.0

0.0 20.0 40.0 60.0 80.0

EC (ug/m3)

B

C (u

g/m

3)

Smoke ch

Filter ch

Air ch smoke chamber BC and EC 

correlation

0.0

0.1

0.2

0.3

0.4

0.5

0.0 0.1 0.2 0.3 0.4 0.5

CL 5036 (1st boiler) 

Comparison between Black Carbon and Elemental Carbon

During Animal Study
HH E2300 (Red Oak; 5/13-5/21)

y = 1.1215x + 13.688

R

2

 = 0.8515

0.0

20.0

40.0

60.0

80.0

100.0

120.0

0.0 20.0 40.0 60.0 80.0 100.0 120.0

EC (ug/m3)

B

C (ug/m3)

Smoke ch

Filter ch

Air ch smoke chamber BC and EC correlation

0

0.1

0.2

0.3

0.4

0.5

0.0 0.1 0.2 0.3 0.4 0.5

E-Classic 2300 (2nd boiler) 

Comparison between Black Carbon and Elemental Carbon

During Animal Study
HH 900 (Wood Pellet; 6/09-6/18)

y = 0.9354x + 40.691

R

2

 = 0.8606

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100

200

300

400

500

600

700

0 100 200 300 400 500 600 700

EC (ug/m3)

B

C (u

g/m

3)

smoke ch

Filter ch

Air ch

Linear (smoke ch)

smoke chamber BC and EC correlation

0

1

2

3

4

5

0 1 2 3 4 5

ACT Pellet (3rd boiler)

Comparison between Black Carbon and Elemental Carbon

During Animal Study

Without one sample

R2=0.26
Summary

 During Full Combustion Cycle

• Emission of carbonaceous gas components (CO, CO2, CH4, and non-methane total 

hydrocarbons) as well as PM reduced as wood being consumed.

• For CL5036 and E-classic 2300, above emissions were notably reduced during damper closing. 

• Improvement of boiler (CL5036 to E-classic 2300) slightly reduced the ratio of organics to black 

carbon emission.

 During Smoldering Condition (Animal study)

• The specific animal exposure condition and EC sample loading issue limited EC and BC data not 

being normally distributed.

• Red oak emitted much more organic carbon than elemental carbon as compared to wood pellet 

that emitted comparable level of elemental and organic carbon.

• Improvement of boiler (CL5036 to E-classic 2300) did not change the ratio of elemental carbon to 

total carbon at smoldering combustion condition.

• Comparison between elemental carbon and black carbon showed reasonable agreement for two 

boiler fueled by Red Oak (R2=0.60 and 0.85).

• EC and BC emission varied at a larger degree for wood pellet boiler during the animal exposure 

as compared to CL5036 and E-classic 2300 because of frequent changes in combustion 

condition.