Arifa Lodhi and Badar Ghauri

Pakistan Space And Upper Atmosphere Research Commission (SUPPARCO), P. O. Box 8402, University Road, Karachi-75270,

Pakistan

 

AEROSOL ANALYSIS AND SOURCE APPORTIONMENT IN URBAN AREA, LAHORE

PAKISTAN

Presentation Overview Air Quality Monitoring Results of four winter studies (1999, 2000,

2001, 2005) Source Apportionment-Application of SO4

2-/Se Tracer technique, Statistics analysis, Factor analysis

Local and distant source identification Future plans

Sampling Location Aerosol Samples were collected at Lahore, which is the capital of Punjab and the second largest city in Pakistan with a population of 7 million.

Sampling Details

• Aerosol Sampling (PM2.5) was carried out during last few winters on following Dates:

1. January 1-5 1999

2. December 25-31, 1999 and January 1-8, 2000

3. January 9-11 2001 sampling interval was 5 min.

4. Nov. 21 2005 to Dec. 9, 2005

• During winter, northeastern Pakistan is under the influence of a high-pressure system resulting in dry weather and low wind speeds. These conditions are ideal for accumulation of pollutants in the atmosphere.

SUPARCO OFFICE

WaghaBhati Gate

Lhr. Cantt

Township

 

METHODOLOGY

(i) The samples were collected on 47-mm Zelfluor (Teflon) filters using Millipore Swinex holder trains.

(ii) Thermo Electron Corporation RAAS PM2.5 Aerosol Sampler

(iii) Black Carbon/Elemental Carbon and Organic Carbon Magee Scientific Model AE21 Aethalometer

Analysis Carried out for following parameters (Wadsworth Center, NY State Department of Health)

a) Anions & Cations (Ion Chromatograph)

b) Trace and Toxic metal (ICP-MS)

Mean Concentration and Range of Trace Species

STUDY 1 January 1-5 1999

S.No. Species Mean Max Min

1  SO42- 50.29 98.90 17.50

2  NO3- 37.03 65.50 22.80

3  Cr 19.00 28.20 5.70

4 Sc 1.34 2.30 0.10

5 Fe  4944.67 8767 535

6  Zn 1253.56 3892 301

7 Se 7.74 11.70 5.10

8  As 13.13 25.30 6.80

9  Sb 19.07 61.90 4.80

Concentrations of SO4 2-, NO3-, are in µg/m3, other in ng/m3.

S.No. Species Mean Max Min

1  SO42- a 43.2 141.3 3.78

2  NO3- a 31.7 74.5 3.1

3  SO2 a 21.2 68.5 0.83

4  Se 26.1 257.6 0.73

5  As 10.6 25.97 1.94

6  Sb 13.1 84.8 0.69

7  Cu 843.9 5305 29.4

8  Zn 2200 7796 111.5

9  Pb 846 4786 31.1

10  Al 13391 54351 1004

11  Fe 8176 24197 741.8

12  Ca 8696 30811 1312

13  Mg 1078 4409 101

14  Cr 22.1 67.6 1.44

15  Mn 177.1 503.9 16

16  Co 3.33 9.53 0.28

17  Ni 16.5 55.6 1.53

a Concentrations of SO4 2-, NO3-, and SO2 are in µg/m3, other in ng/m3.

STUDY 225 December 1999 to 8th January 2000

Mean Concentration and Range of Trace Species

the two sampling time intervals of 6 hour periods from 0800 to 1400 and the two sampling time intervals of 6 hour periods from 0800 to 1400 and 1400 to 2000 hours followed by a 12 hour over night period from 2000 to 1400 to 2000 hours followed by a 12 hour over night period from 2000 to 0800 hours.0800 hours.

Date (2001)

Time zone Mean SO2-

4 (µg/m3 )

Se conc. (ng/m3 )

January 9

08:00-10:00 19.02 3.55

12:00-13:15 17.32 2.05

January 10

00:00-02:00 18.64 3.46

08:00-10:00 10.63 3.4

12:00-13:00 27.84 4.02

January 11

00:00-01:00 13.9 0.95

08:00-09:45 8.8 1.87

Summary of 5-min aerosol measurements at Lahore, Pakistan, during January 2001

Concentration (µg/m3) of black carbon at Lahore

 

Date(2005)

 Min.BC

 

 Max. BC

 

 Avg. BC

               

Nov 21 1.6 46.1 14.3Nov 22 6 54.4 18.2Nov 23 3.7 52.8 15.8Nov 24 4.4 38.3 16.5Nov 25 3.2 55.2 12.1Nov 26 4.7 58.8 21.2

Nov 27 11.4 45 21.4

Nov 28 4.8 52.4 14.3

Nov 29 1.5 40.4 10.8

Nov 30 1.7 34.7 12

Dec 01 2.1 57.9 20.9

Dec 02 3.1 68.7 26.3

Dec 03 2.2 56.7 21.4

Dec 04 3.3 51.4 19.5

Dec 05 3.1 57.6 15.9

Dec 06 2.1 76.3 20.7

Concentration (µg/m3) of black carbon at Lahore

STUDY 4Nov. 21 2005 to Dec. 9, 2005

0102030405060708090

100

21-N

ov-0

5

22Nov

.05

23Nov

.05

24Nov

.05

25Nov

.05

26Nov

.05

27Nov

.05

28Nov

.05

29Nov

.05

30Nov

.05

1-Dec

-05

2-Dec

-05

3-Dec

-05

4-Dec

-05

5-Dec

-05

6-Dec

-05

7-Dec

-05

8-Dec

-05

BC

(u

g/m

3)

0

50

100

150

200

250

300

350

400

Mas

s (u

g/m

3)

BC (µg/m3)

MASS (µg/m3)

Time series showing filter mass and BC Concentrations in Lahore, Pakistan

CITY YEAR BLACK CARBON

Kanpur, India

(Tripathi et al)

2005 12.3

Five cities of Bangladesh (Salam et al)

2003 10.1 to 41.3 (EC)

Beijing, China (He at al) 2001 and 2004 8.1 (EC)Measurement of EC in other cities in China by various groups.

2003, 2005, 2006 4.7 to 11.8 (EC)

Mumbai, India (Venkataraman)

2002 12.5 (EC)

Dhaka 2001 22

Lahore 2005 21.7

New York 2002 <2

London 1995 2.3

Concentrations (ug/m3) of Black Carbon/Elemental Carbon in

Metropolitan Areas

STUDY 1January 1-5 1999

SOURCE EVALUATION OF CHEMICAL SPECIES

Application of Tracer technique

STUDY 225 December 1999 to 8th January 2000

0

20

40

60

80

100

120

140

25 27 29 31 2 4 6 8

December 1999-January 2000

Con

c. N

O3,

Se,

As

in u

g/m

3

0

20

40

60

80

100

120

140

Con

c. S

O4

in u

g/m

3

NO-3 (µg/m³)AsX 1000 (µg/m³)SeX1000 ( µg/m³)SO-24 (µg/m³)

0

10

20

30

40

50

60

70

80

90

100

Jan.1 Jan.1 Jan.2 Jan.2 Jan.3 Jan.3 Jan.4 Jan.4 Jan.5

con

c. N

O3

(ug

/m3)

, S

e, S

b,

As

(ng

/m3)

0

20

40

60

80

100

Co

nc.

SO

4 in

ug

/m3

Se *2

NO3 -

Sb

As

SO4-2

Concentrations in ug/m3 of SO42- , NO3

- , Se, As, and Sb in 12 hour samples at Lahore, Pakistan.

Five-min aerosol concentrations of (a) SO4 -2 (nmoles/m3) and (b) Se (pmoles/m3) at Lahore, Pakistan on January 9, 2001. The inverted solid triangles in (b) represents the detection limit

for Se is approx. 20(pmoles/m3). The SO4 -2 /Se ratios are shown in (c).(L. Husain et al 2004)

STUDY 3January 9-11 2001

In January 2001 the sampling interval was 5 min. In January 2001 the sampling interval was 5 min.

Sulfate was good correlated with Se and not with any element indicating their common source, most likely coal combustion

The SO4/Se ratios vary from ~1800 to 10,000 with a mean of 4070 are in the range typically observed at sites in the US and indicative of substantial contributions to sulfate concentration due to the oxidation of SO2.

The sulphate/Se ratio were suggestive of longe-range transport from several hundred kms

Application of Tracer technique

STUDY 1January 1-5 1999

S.No. Species

Factor

1 2 3

1 Fe 0.976

2 Sc 0.973

3 Cr 0.966

4 Sb 0.985

5 As 0.898

6 Zn 0.870

7 SO42- 0.876

8 Se 0.875

9 NO3- -0.603 0.701

Rotated Factor Analysis of Aerosol Data

Factor loadings less than 0.4 have been omitted.

Statistics analysis

S.No. Species 1 2 3 4

1 Al 0.980

2  Mg 0.977

3  Fe 0.967

4 Co 0.963

5 Cr 0.952

6  Mn 0.935

7  Ca 0.923

8 Ni 0.695 0.573

9  As 0.522 0.590 0.414

10  Pb 0.965

11 Sb 0.828 0.477

12  Zn 0.661

13  SO42- 0.958

14  NO3- 0.841

15  Se 0.951

16  Cu 0.469 0.470

Rotated Factor Analysis of Aerosol Data

Factor loadings less than 0.4 have been omitted

STUDY 225 December 1999 to 8th January 2000

Element Crustal concentration (ppm)

Aerosol concentration (ng/m3)

EFa R2

Al 81300 13392 1 1

Fe 50000 8176 0.99 0.940

Ca 36300 8696 1.45 0.819

Mn 950 177.1 1.13 0.895

Cr 100 22.1 1.34 0.90

Ni 75 16.5 1.33 0.91

Co 25 3.33 0.81 0.927

Zn 70 2333 202.3 0.096

Cu 55 843.9 93.2 0.253

Pb 13 846 395 0.020

Se 0.05 20.6 2498 0.011

As 1.8 10.8 36.5 0.388

Sb 0.2 13.3 405 0.015

Crustal Enrichment Factors of Trace Elements

aEnrichment factor =(Xair/Alair)(Xcrust/Alcrust)

STUDY 225 December 1999 to 8th

January 2000

Indian Ocean Experiment (INDOEX):Indian Ocean Experiment (INDOEX):

The high levels of pollutants especially aerosol sulfate The high levels of pollutants especially aerosol sulfate concentration were observed may be due to local sources and concentration were observed may be due to local sources and extensive coal utilization of coal in Indian power plants. extensive coal utilization of coal in Indian power plants.

The high level of BC may be due local activities such as The high level of BC may be due local activities such as frequent garbage burning, diesel combustion, sugar mill and bick frequent garbage burning, diesel combustion, sugar mill and bick kilin activities around the city.kilin activities around the city.

A detailed scientific investigation of aerosol chemistry has A detailed scientific investigation of aerosol chemistry has been initiated at multiple sites in Lahore been initiated at multiple sites in Lahore

The control measures are required to be placed because of The control measures are required to be placed because of potential threat to the inhabitants of the region where millions of potential threat to the inhabitants of the region where millions of people live. people live.

Conclusion and Future plansConclusion and Future plans

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