Breathe in Delhi and you stand a good chance of getting cancer
the crowds thronging Janpath, Delhi's premier shopping mall in Connaught Place, are blissfully unaware of the serious health risk due to the alarming level of cancer-causing benzene in the air. The new indicative data on benzene levels, available from an investigation done by a foreign scientist, is a rebuke to the Indian air quality regulators.
M P Keuken of tno Netherlands Institute for Applied Research, who conducted the study, said the air concentration of benzene in central Delhi exceeds the air quality standards of the European Union by as much as 10 times. The air samples were taken in October 1996. Since then, the situation may well have worsened.
Keuken made this revelation at a workshop on Integrated Approach To Vehicular Pollution control. The workshop was jointly organised by the World Bank and Government of Delhi.
In the west of Janpath, the concentration of benzene measured was as high as 139 g/m 3 , and in the east, it was 115 g/m 3 , Keuken reported. The average level of benzene measured at all the sites in the heart of the capital exceeded 120 g/m 3 s -- which is alarmingly high when compared to other cities in the world. Keuken concludes that high level of benzene and other aromatics including xylene, and toluene in the atmosphere indicate that most of it is coming from exhaust emissions and evaporation losses of petrol and diesel during storage and distribution.
Keuken finds a correlation between traffic intensity and the level of benzene at the monitoring sites. His survey shows that among the monitoring sites, the daily average traffic load was 30,000 petrol vehicles in Janpath, 2,20,000 cars and buses at Northern Railway Bridge, and 22,000 petrol vehicles in Connaught Place. The high value of benzene at the Northern Railway Bridge indicates that diesel buses are an important source of benzene pollution.
Ironically, even as the Central Pollution Control Board ( cpcb) shows no interest in monitoring benzene in India, Keuken is apologetic about his efforts. He says: "This test was performed without the consent of the appropriate authority in India for which I apologise. The driving force behind this activity was scientific curiosity and the fact that I lived in Delhi for five years."
The apology is tendered for generating such crucial information on a toxic gas which has been classified by the International Agency for Cancer Research as definite human carcinogen. Although the European Union has regulated standards for air-borne benzene at 10 g/m 3 , the World Health Organisation says that there is no safe level for airborne benzene. The toxic effects of benzene in humans include damage to the central nervous system and immune system.
D K Biswas, chairperson, cpcb, argues that the immediate monitoring is not possible because of the high cost involved in monitoring benzene. Keuken, however, had indicated in his research papers that cost-effective methods were available to collect reliable information on the air quality and could be adequate tools to establish a low-cost monitoring network in urban areas.
Keuken has stressed the point that his limited survey was only indicative of the alarming situation in Delhi. But there was a need for more elaborate and detailed survey to assess the current pollution levels.
Keuken's findings have evoked strong responses from some Indian experts. H B Mathur, who chaired the committee to set mass emission standards for vehicles in 1992, feels that benzene monitoring should be taken up on a priority basis particularly in view of the fact that fuel with high level of aromatics and benzene is consumed in India. "We have introduced unleaded petrol in a great hurry without lowering the level of benzene to a desirable level. It is more than five per cent in unleaded fuel whereas the rest of the world is moving ahead to meet the limit of one per cent."
Benzene is a constituent of crude oil. While manufacturing unleaded oil, benzene is maintained at higher levels to increase octane number to prevent knocking of the engine. In light of this evidence warns Mathur, "It is about time that the cpcb took note of this lethal toxic trail."
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