Arifa Lodhi and Badar Ghauri

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AEROSOL ANALYSIS AND SOURCE APPORTIONMENT IN
URBAN AREA, LAHORE PAKISTAN
Arifa Lodhi and Badar Ghauri Pakistan Space
And Upper Atmosphere Research Commission
(SUPPARCO), P. O. Box 8402, University Road,
Karachi-75270, Pakistan  
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Presentation Overview

• Air Quality Monitoring
• Results of four winter studies (1999, 2000,
  2001, 2005)
• Source Apportionment-Application of SO42-/Se
  Tracer technique, Statistics analysis, Factor
  analysis
• Local and distant source identification
• Future plans

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• 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
• January 1-5 1999
• December 25-31, 1999 and January 1-8, 2000
• January 9-11 2001 sampling interval was 5 min.
• 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.

Wagha
Bhati Gate
Lhr. Cantt
SUPARCO OFFICE
Township
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•  
• METHODOLOGY
• The samples were collected on 47-mm Zelfluor
  (Teflon) filters using Millipore Swinex holder
  trains.
• 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)
• Anions Cations (Ion Chromatograph)
• Trace and Toxic metal (ICP-MS)

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STUDY 1 January 1-5 1999
Mean Concentration and Range of Trace Species
Concentrations of SO4 2-, NO3-, are in µg/m3,
other in ng/m3.
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STUDY 2 25 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 1400 to 2000 hours
followed by a 12 hour over night period from 2000
to 0800 hours.
a Concentrations of SO4 2-, NO3-, and SO2 are
in µg/m3, other in ng/m3.
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Summary of 5-min aerosol measurements at Lahore,
Pakistan, during January 2001
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Concentration (µg/m3) of black carbon at Lahore  
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Concentration (µg/m3) of black carbon at Lahore
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STUDY 4 Nov. 21 2005 to Dec. 9, 2005
Time series showing filter mass and BC
Concentrations in Lahore, Pakistan
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Concentrations (ug/m3) of Black Carbon/Elemental
Carbon in Metropolitan Areas
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Application of Tracer technique
SOURCE EVALUATION OF CHEMICAL SPECIES
STUDY 1 January 1-5 1999
STUDY 2 25 December 1999 to 8th January 2000
Concentrations in ug/m3 of SO42- , NO3- , Se,
As, and Sb in 12 hour samples at Lahore, Pakistan.
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STUDY 3 January 9-11 2001
In January 2001 the sampling interval was 5 min.
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)
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Application of Tracer technique

• 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
  

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STUDY 1 January 1-5 1999
Statistics analysis
Rotated Factor Analysis of Aerosol Data
Factor loadings less than 0.4 have been omitted.
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Rotated Factor Analysis of Aerosol Data
STUDY 2 25 December 1999 to 8th January 2000
Factor loadings less than 0.4 have been omitted
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STUDY 2 25 December 1999 to 8th January 2000
Crustal Enrichment Factors of Trace Elements
aEnrichment factor (Xair/Alair)(Xcrust/Alcrust)
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Indian Ocean Experiment (INDOEX)
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Conclusion and Future plans

• The high levels of pollutants especially
  aerosol sulfate concentration were observed may
  be due to local sources and extensive coal
  utilization of coal in Indian power plants.
• The high level of BC may be due local
  activities such as frequent garbage burning,
  diesel combustion, sugar mill and bick kilin
  activities around the city.
• A detailed scientific investigation of
  aerosol chemistry has been initiated at multiple
  sites in Lahore
• The control measures are required to be
  placed because of potential threat to the
  inhabitants of the region where millions of
  people live.

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THANK YOU