DIMAPUR, July 21 – Air pollution in Nagaland’s commercial hub Dimapur, particularly during the dry season, is crossing permissible limits. This is stated by the Nagaland Pollution Control Board (NPCB) in a report on the ‘Air Quality Status of Dimapur city during 2010 & 2011’.
The NPCB has been monitoring the ambient air quality of Dimapur for the last 10 years at two stations located at Bank Colony and Dhobinala. Four air pollutants are monitored and analysed, namely Nitrogen dioxide (NO2), Sulphur dioxide (SO2), Respirable Suspended Particulate Matter (RSPM) and Suspended Particulate Matter (SPM).
The monitoring of pollutants is carried out for 24 hours (4 hourly sampling for gaseous pollutants (NO2 & SO2) and 8 hourly sampling for particulate matter (RSPM & SPM)).
In the year 2011, the average concentration of RSPM was found to be highest in the month of January at both the stations – Bank Colony (317) with158 µg/m3 and Dhobinala (448) with 166 µg/m3 exceeding the permissible limit of 100 µg/m3. The lowest reading of RSPM was recorded in the month of July with 20 µg/m3.
However, it said the gaseous pollutants, namely Nitrogen Dioxide and Sulphur Dioxide are within permissible limits at both stations.
The NPCB said the data for the years 2010 & 2011 show that the RSPM for both the stations indicates slight variations, except in the month of January 2011, at Bank Colony. In the case of Dhobinala station, the variations during the year 2011 are higher compared to 2010.
The Board also pointed out that both RSPM and SPM concentration increase in dry season because of bad road condition which raises dust through vehicular movement or wind after which particulate matters take time to settle down. The increasing population and number of automobiles and other small scale industries such as stone crushers, sand mahals, vulcanisation, and improper waste management may be the other reasons for the increased air pollution, it said.
Stating that the records had been taken from the permanent stations at Dhobinala and Bank Colony, the NPCB said variations can be expected from colony to colony.
However, pointing out that this is evidence that air pollution, in Dimapur is definitely crossing permissible limits, the Board has strongly recommended implementation of remedial measures such as improving the road, relocating polluting industries to the outskirts, relocating sand mahals, better waste management, and maintaining green cover to improve the ambient air quality of Dimapur city.