Data used for Yale study wasn't authentic: Centre

The times of India , Wednesday, February 05, 2014
Correspondent : Jayashree Nandi
NEW DELHI: While Yale University researchers have claimed they couldn't find "reliable and accurate" air quality data from India, the Centre has expressed doubts over the veracity of satellite data Yale has used for Environment Performance Index 2014. System of Air Quality Weather Forecasting and Research under the ministry of earth sciences stated in a statement issued on Friday that the ranking should have been based on ground level data which gives an authentic picture of air pollution.

"The report does not consider any Indian ground-based measurements of air quality which is the most accurate method so far. Non-uniform and incomplete sampling by satellites have the potential of creating bias. Satellite samples are from one location at one particular time in a day. Since this technique does not have capability to take measurements during cloudy conditions when air quality is best in India, it cannot consider good data for that period," says a statement by SAFAR. "Sampling error of satellite-derived PM2.5 is larger in regions influenced by biomass burning, mineral dust, or persistent cloud. Hence, concluding something based on such uncertain factors may be seen with precaution," it adds.

Scientists at SAFAR told TOI that Indian agencies could have given the required data to Yale researchers if they had asked. They, however, did not deny that air quality was indeed very poor in India.

Angel Hsu, lead author of EPI, clarified that they have used only satellite data for assessment. "We produce country-level aggregations of average exposure to fine particulate matter (PM2.5) using satellite data processed by research teams at Yale, Columbia, and Dalhousie Universities," Hsu said.

Many agreed with Yale researchers, though, on lack of reliable air quality data in India.

"We have real time monitoring only for major cities but it has to be implemented in Tier II cities. Our manual monitoring stations outnumber automatic ones which is why the data eventually reported is not credible and often conservative. However, Delhi is now in position to replicate robust monitoring like that of China by including an air quality index and a health advisory. They should do it soon," Anumita Roychowdhury, head of air pollution and clean transportation programme at Centre for Science and Environment, said.

 
SOURCE : http://timesofindia.indiatimes.com/city/delhi/Data-used-for-Yale-study-wasnt-authentic-Centre/articleshow/29873797.cms
 


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