December 22, 2008 1:28:43 am
While the United Nations Environment Programme (UNEP) report on Atmospheric Brown Clouds forming over Northern India has set alarm bells ringing, Delhi has reason to cheer.
Air quality data compiled over the last year under a new air monitoring system set up by the Delhi Pollution Control Committee (DPCC) at 40 spots in the city shows that air pollution has not risen substantially and largely, Delhi is better placed now than in December last year. This has led experts to believe that the thick haze over the city s seen in November was caused by frenetic road-laying and construction activities taking in the Capital and not vehicular pollution.
The latest air quality data taken by the Delhi Pollution Control Committee reveals that most indicators of air pollution levels: Suspended Particulate Matter (SPM), Respirable Suspended Particulate Matter (RSPM) and Nitrogen Oxides have remained at earlier levels or have reduced, while Carbon Monoxide and Sulphur Dioxide have shown an upward trend.
SPM and RSPM (the more dangerous of the two as it gets ingested in the trachea) are the main causes for haze. But November’s winter data suggests that Delhi is better placed than winter last year. December 2007 had an SPM level of 559 mg/metre cube, while November this year has registered 536 mg/metre cube.
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RSPM, a major cause for asthma, is substantially lower compared to December last year. While December 2007 had 313 mg/metre cube and August had this year registered 283 mg/metre cube, November has registered RSPM levels of 247 mg/metre cube.
Interestingly, the data shows that RSPM and SPM levels are high in the same areas, suggesting that causes for both might be the same. Sarita Vihar area in the Capital has the highest levels of both SPM and RSPM.
“The data suggests that the haze seen this winter could be due to the dust raised by road-laying and construction activities. Moreover, in winters, the mixing levels of pollutants come closer to the ground. Only rainfall or high temperatures can disperse this smoggy formation,”’ says a senior DPCC scientist.
On the upside, Nitrogen Oxides levels have considerably dipped this winter and are now within permissible limits: last December registered 94 mg/metre cube (above the permissible levels of 80 mg/metre cube) while the figures stand at 49 mg/metre cube for November this year.
Carbon Monoxide, on the other hand, which hovered around a steady level of 900 mg/metre cube, has gone up to 1,181 mg/metre cube in November. Paharganj is the worst off in terms of CO pollution.
The data also confirms that areas close to the Ridge fare the best. Areas like Inderpuri, Rajpur Road, Lawrence Road, Mehrauli and Vasant Kunj have registered steady, and low, levels of pollution.
“The purpose of the DPCC exercise of setting up air quality monitoring systems at 40 spots in the city was to get a sense of the air quality in both industrial and residential areas. We thus chose wholly residential areas like Rajpur Road as well as busy commercial areas like Paharganj,” said an official. “The data from Delhi registers a positive trend and we are happy with this,” the official added.
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