wAbstract
@Total Suspended Particulate matter (TSP) in urban atmosphere
of Islamabad was collected using a high volume sampling technique
for a period of one year. The nitric acid-perchloric acid extraction
method was used and the metal contents were estimated by atomic
absorption spectrophotometer. The highest mean concentration was
found for Ca at 4.531 สg/m3, followed by Na (3.905
สg/m3), Fe (2.464 สg/m3), Zn (2.311 สg/m3),
K (2.086 สg/m3), Mg (0.962 สg/m3), Cu (0.306
สg/m3), Sb (0.157 สg/m3), Pb (0.144 สg/m3)
and Sr (0.101 สg/m3). On an average basis, the decreasing
metal concentration trend was: CaNaFeZnKMgCuSbPbSrMnCoNiCrLiCdเAg.
The TSP levels varied from a minimum of 41.8 to a maximum of 977
สg/m3, with a mean value of 164 สg/m3, which
was found to be higher than WHO primary and secondary standards.
The correlation study revealed very strong correlations (r0.71)
between Fe-Mn, Sb-Co, Na-K, Mn-Mg, Pb-Cd and Sb-Sr. Among the
meteorological parameters, temperature, wind speed and pan evaporation
were found to be positively correlated with TSP, Ca, Fe, K, Mg,
Mn and Ag, whereas, they exhibited negative relationships with
relative humidity. On the other hand, Pb, Sb, Zn, Co, Cd and Li
revealed significant positive correlations with relative humidity
and negative with temperature, wind speed and pan evaporation..
The major sources of airborne trace metals identified with the
help of principle component analysis and cluster analysis were
industrial emissions, automobile exhaust, biomass burning, oil
combustion, fugitive emissions, resuspended soil dust and earth
crust. The TSP and selected metals were also studied foe seasonal
variations, which showed that Na, K, Zn, Cu, Pb, Sb, Sr, Co and
Cd peaked during the winter and remained lowest during the summer,
while Ca, Fe, Mg and Mn were recorded highest during the spring.
Keywords: AAS; Cluster analysis; Meteorological variations; Principal
component analysis; Seasonal variations; TSP; Trace metalsx
1 Introduction
2 Experimental
@2.1 The study area
@2.2 Sampling
@2.3 Extraction procedure and analysis
@2.4 Statistical analysis
3 Results and discussion
@3.1 Airborne metal distribution for the annual period
@3.2 Meteorological variations during the study period
@3.3 Correlation study of TSP and metals for the annual period
@3.4 TSP and metal correlations with climatic parameters for the
annual period
@3.5 Source apportionment
@3.6 Seasonal variations in airborne TSP and metal levels
4. Conclusions
Acknowledgements
References