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OZONE BIOMONITORING IN PAKISTAN USING TOBACCO CULTIVAR BEL-W3
KAFIATULLAH1, ABDUL WAHID2,
SHEIKH SAEED AHMAD3* AND SYED RAZI ABBAS SHAMSI1
Abstract:
The present study depicts a comparison of ozone (O3)
concentrations over a decade time (1993-94 to 2006) using plant
biomonitoring and continuous ozone monitors techniques in Lahore city of
Pakistan. The variations in O3 levels were assessed at city
centre, suburbs and semi-rural/rural locations in and around the city of
Lahore by using American O3-sensitive tobacco biomonitor
plant (Nicotiana tabaccum L. cv. Bel-W3) for the first time in
Pakistan during 1993 and 1994 seasons through weekly assessment of
visible damage to leaves. Results for both 1993 and 1994 seasons
indicated significant differences between sites in the mean 6-h O3
concentrations with a range of over 20 ppb and 15 ppb across the sites
in 1993 and 1994, respectively. An inverse relationship between the
levels of NO2 and O3 was found during
investigation. The highest O3 levels of 75-80 ppb were found
at rural areas and the lowest at city centre sites. The extent of O3
injury on the tobacco cv. Bel-W3 leaves reflected the trends seen in O3
concentrations. The highest and lowest leaf injury indices of 18-27% and
5-7% occurred at the rural and city centre sites, respectively. Results
for 2006 season indicated the highest seasonal mean O3
concentration of 100 ppb in semi-rural areas compared with city centre
sites (68 ppb). The highest 26% and 20% increase in O3 levels
was observed at rural/semi-rural and city centre sites, respectively
when compared with 1993 O3 survey. Application of O3
biomonitoring technique proved very cost-effective and feasible for the
estimation of atmospheric O3 levels in South East Asian
regions like Pakistan where shortage of electric supply, trained man
power and poverty is already playing havoc.
1Department
of Botany, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590,
Pakistan
2Department
of Environmental Science, Bahauddin Zakariya University, Multan-60800,
Pakistan
3Department
of Environmental Sciences, Fatima Jinnah Women University, Rawalpindi,
Pakistan
*Corresponding author’s
e-mail:
drsaeed@fjwu.edu.pk
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