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SURFACE ozone is produced as a result ofchemical reactions in the atmosphere,driven by the action of ultra-violet (UV)radiation in the sunlight, involving bothnitrogen oxides (NOX) and volatileorganic compounds (VOCs). While bothNox and VOCs are emitted in largeamounts by motor vehicles, otherimportant sources of VOCs include solvents used in industrial and chemicalprocesses.
The British team comprising J N BBell, M R Ashmore and R Maggs, of thedepartment of biology, ImperialCollege, London, in collaboration withA Wahid and S R A Shamsi, of thedepartment of botany, University ofPunjab, Lahore, studied the impact ofambient air pollution on wheat and riceyields in the vicinity of Lahore.
Their study demonstrated reductions of 42 per cent and 37 per cent inthe case of grain yields of two cultivarsof rice (Oriza sativa L) and 46.7 per centand 34.8 per cent in the grain yields oftwo cultivars of winter wheat (Triticumaestivum L). Says Bell, "The very largeyield reductions found in this study andthe fact that surface ozone - a secondary pollutant that can spread in highconcentrations over rural areas may be amajor contributor to the observedeffects - suggests the potential impactof air pollution". The British team madesimilar observations while studying theimpact of surface ozone on Egyptianvarieties of vegetables in Alexandria.
"A comprehensive scientific studyon crop losses due to air pollution, particularly the impact of surface ozone indeveloping countries, is most urgentlyrequired. This will help in a genericanalysis of the issue, which is essentialfor assessing the scale of the problem atnational and global levels, as also forproviding an environmentally soundbasis for agricultural policies," arguedBell while addressing a workshop on theeffects of air pollution on crop yields inIndia, organised by the School ofEnvironmental Sciences, JawaharlalNehru University, New Delhi.
The British team's visit to India wasaimed at soliciting the assistance ofIndian scientists on a project that wouldseek to examine the relation between airpollution and agricultural productionwithin the country. India was selectedfor the proposed study because theproblems of air pollution and its impacton the country's vegetation has been asubject of interest for the past severalyears. Also, a number of research groupsare already working in this field. But -according to Ashmore - little has beendone by way of establishing the effects ofsurface ozone on crop physiology andgrowth in the rural areas.
The ambitious proposals put forthby the Imperial College team , duringthe course of the two-day seminar,generated considerable interest amongIndian scientists. The propositionsincluded a plan to collate data on airpollution levels in India and extendmeasurements of surface ozone andnitrogen oxides to more rural sites. Sixresearch centres were to be establishedthroughout the country to conductexperiments in rural locations to assessthe impact of surface ozone on cropgrowth, apart from identifying local cultivars; of major crops which may be sensitive or resistant to air pollution,among others.
But the enthusiasm diminishedtowards the end of the second day ofthe conference because the British teamultimately announced that theycould offer a grant of just Rs 600,000through the Overseas DevelopmentAdministration (ODA) for the researchto be conducted over a period oftwo years. The limited fundingsubstantially scaled down the objectivesof the Indian case study to a merereviewing and synthesising of theexisting data available on the subject,The results of the case study would beused to evolve a project proposal forsoliciting additional external funding ata later stage.