Kok Sothea and Nguyen Thi Kim Oanh

Environmental Engineering and ManagementSchool of Environment, Resources and Development

Asian Institute of Technology

POLYCYCLIC AROMATIC HYDROCARBON (PAHs) LEVELS AND CONTRIBUTING SOURCE IN PHNOM PENH, CAMBODIA

Presentation Itinerary

2

3 Sampling Locations and Sampling Plan

4 Results and Discussions

1 Background

2 Research Objective

5 Conclusions

• The sources and levels of Particulate Matter (PM) and PAHs emissions are both spatially and temporally varied.

• Several studies show that high concentrations of PAHs generally occur in urban areas especially in Asian developing countries.

• Several studies conducted in Cambodia, but they mainly focus on, coarse particles bound PAHs.

• No study has been found to focus on the fine particle-bound PAHs and gas bound PAHs in the country.

• The fine particle bound PAHs should be monitored to provide useful information on the contribution of the sources to the atmospheric PAHs and the associated health effects.

Background

3

To determine the ambient levels phase distribution of PAHs and contributing sources by receptor modeling in Phnom Penh

Sampling Locations

• Located in the city center

• Close to road site• 11 m above the

ground

Urban Traffic Site

Sub-urban

Residential Site

12

1

2

• Located in the sub-urban city

• 8 m above the ground

Population ~ 2 MVehicle ~ 1.2 M

Ambient Air Quality Sampling Plan

5

PAHs

Element

sIons

PAHs BC

Elements

Ions

BC

2 QFFs (47mm) Samples and 1 PUF for each PM2.5 and

PM10 at UT Site

PU

F PU

F

Cut into 4 parts

PM2.5 and PUF Sample at SR Site

PAHsPAHs

1st QFF 2nd QFFQFF (90mm)SR Site (URG-3000B) UT Site (URG-3000ABC)

PM2.5

PU

F

PM2.5PM2.5 PM10PM`10

PM2.5

PU

F

QFF (47mm), PUF (30mm)QFF (90mm), PUF (50mm)

• Sampling period: Feb 2016 to Jan 2017

• Sampling frequency: once/ 4 days (Dry)

and once/6 days (wet)

• Sampling duration: 24 hours

• Put in petri dish and conditions at (40 ± 5% RH, 22 ±

30C) of 24-hrs for QFF

• PUF refrigerated till extraction

PU

F

PM2.5PM2.5

PU

F

PM10PM`10

PM mass concentration by gravimetric/microblance

Pre-weight QFF and pre-clean PUF

PU

F

PU

F

GC-MS

24hr PM Levels in Phnom Penh

6

-

20

40

60

80

100

120

140

23-F

eb-1

6

4-M

ar-1

6

14-M

ar-1

6

24-M

ar-1

6

3-A

pr-

16

13-A

pr-

16

23-A

pr-

16

3-M

ay-1

6

13-M

ay-1

6

23-M

ay-1

6

2-J

un-1

6

12-J

un-1

6

22-J

un-1

6

2-J

ul-

16

12-J

ul-

16

22-J

ul-

16

1-A

ug-1

6

11-A

ug-1

6

21-A

ug-1

6

31-A

ug-1

6

10-S

ep-1

6

20-S

ep-1

6

30-S

ep-1

6

10-O

ct-1

6

20-O

ct-1

6

30-O

ct-1

6

9-N

ov-1

6

19-N

ov-1

6

29-N

ov-1

6

9-D

ec-1

6

19-D

ec-1

6

29-D

ec-1

6

8-J

an-1

7

PM

conc.

(µ

g/m

3)

PM2.5 (Urban)PM10 (Urban)

-

10

20

30

40

50

60

23-F

eb-1

6

4-M

ar-1

6

14-M

ar-1

6

24-M

ar-1

6

3-A

pr-

16

13-A

pr-

16

23-A

pr-

16

3-M

ay-1

6

13-M

ay-1

6

23-M

ay-1

6

2-J

un-1

6

12-J

un-1

6

22-J

un-1

6

2-J

ul-

16

12-J

ul-

16

22-J

ul-

16

1-A

ug-1

6

11-A

ug-1

6

21-A

ug-1

6

31-A

ug-1

6

10-S

ep-1

6

20-S

ep-1

6

30

-Sep

-16

10-O

ct-1

6

20-O

ct-1

6

30-O

ct-1

6

9-N

ov-1

6

19

-No

v-1

6

29-N

ov-1

6

9-D

ec-1

6

19-D

ec-1

6

29-D

ec-1

6

8-J

an-1

7

PM

conc.

(µ

g/m

3)

PM2.5 (Residential)

PM10: 15 to 119 µg/m3 (58 µg/m3)

PM2.5: 8 to 85 µg/m3 (36 µg/m3)

PM2.5: 7 to 53 µg/m3 (29 µg/m3)

Same Pattern over time

• Urban PM2.5:

22% >

Cambodia Standard (50 µg/m3)

• Residential

PM2.5: 6% >

Cambodia Standard

PAHs Levels in Phnom Penh

7

-

20

40

60

80

100

120

PPAHs GPAHs PPAHs GPAHs PPAHs GPAHs

PM2.5 PM10 PM2.5

Urban Residential

PA

Hs

(ng/m

3)

NAP AcPy ACE Flu PHE ANTFL PYR BaA CHY BbF BkFBaP IND DBA BghiP

• Urban:

• GPAHs (PM2.5): 96 ng/m3 74% of

TPAHs; PPAHs: 32 ng/m3

• GPAHs (PM10 ): 89 ng/m3 69% of

TPAHs; PPAHs: 43 ng/m3

• Residential: • GPAHs: 53 ng/m3 65% of TPAHs;

PPAHs :29 ng/m3

-

20

40

60

80

100

120

140

PPAHs GPAHs PPAHs GPAHs PPAHS GPAHs

PM2.5 PM10 PM2.5

Urban Resident

PA

Hs

Con. (n

g/m

3)

Seasonal PAHs Levels in PNH

8

• No significant differences

between the levels of PAHs in

dry and wet season

• local emission sources did

not significantly vary

between the two seasons.

• the traffic volume did not

fluctuate much by season

• Intensity of traffic

congestion was more

severe during the rainy

days compared to dry

days.

-

20

40

60

80

100

120

140

PM2.5 PM10 PUF PM2.5 PUF

Urban Residential

ng

/m3

Dry Season

Wet Season

PAH source apportionment (CMB)

9

52%

18%

22%

1%7%

Diesel vehicles

Gasoline vehicle

Woodcombustion

Charcoalcombustion

Unexplained

44%

18%

14%

24%

Diesel vehicles

Gasoline vehicle

Wood combustion

Unexplained

10%2%

33%

1%

54%

Diesel vehicles

Gasolinevehicle

Woodcombustion

Charcoalcombustion

Unexplained

19%

1%

18%

3%

59%

Diesel vehicles

Gasoline vehicle

Woodcombustion

Charcoalcombustion

Unexplained

Urban PM2.5 (Wet)

Urban PM2.5 (Dry)

Resident PM2.5 (Wet)

Resident PM2.5 (Dry)

• Biomass combustion (domestic cooking and solid waste burning) contributed >50%

• Lower contribution from mobile source ~20%

• Contributing sources quantified by EI and CMB →mobile source < biomass combustion

PAHs Emission Inventory, 2015

10

2%

24%

28%

26%

20%

Industrial Generator Combusion

Commerical Generator Combustion

Power Plant

Domestic Cooking

Solid Waste Burning

Mobile source

PAHs=

8.6ton/year

• High PM and PAHs levels found in the urban sites as comparedto residential site.

• Higher PM and PAHs levels were in dry season. For PAHs, nosignificant difference between the seasons which may largelycontributed by local sources.

• The main sources of PAHs emission in PNH are mobile sourceand biomass combustion.

• Emission inventory can be used to characterize the sourceprimary pollutants and CMB-a receptor model can used toquantify the contributing to PAHs, but selection of source profileis a challenge.

• Further studies: PMF for PM and PAHs

Conclusions

11