Nagaland Pollution Control Board (NPCB) has found out that that in 2011, two station in Dimapur – Bank colony and Dhobinala exceeded Respirable Suspended Particulate Matter (RSPM) permissible limit.
NPCB has also suggested that to control dust particles during dry season from crossing the permissible limits in Dimapur, remedial measures such as improving the road, relocating polluting industries to outside the city limits, relocating sand mahals, better waste management and maintaining green cover should be implemented to improve the ambient air quality of Dimapur.
In a statement highlighting air quality status of Dimapur during the year 2010 & 2011, NPCB said that the board had been monitoring the ambient air quality of the state’s commercial hub for the last 10 years in two stations located at Bank colony and Dhobinala.
Four air pollutants — Nitrogen dioxide (NO2), Sulphur dioxide (SO2), RSPM and Suspended Particulate Matter (SPM) — were monitored and analyzed.
The monitoring of pollutants was 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 the highest in the month of January in both the stations i.e. 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.
The gaseous pollutants i.e. Nitrogen dioxide (NO2) and Sulphur dioxide (SO2) were within the permissible limits in both the stations.
The data for the year 2010 & 2011 showed that RSPM for both the stations slight variations except in the month of January 2011 in Bank colony. While in the case of Dhobinala station the variations during the year 2011 was higher compared to 2010.
Both RSPM and SPM concentration increased in dry season because the bad road condition; raising dust by the vehicular movement or wind and particulate matters do not settle down quickly.
The increasing population and increased in number of automobiles and other small scale industries such as stone crushers, sand mahals, vulcanization, and improper waste management might be the other reasons for the increased air pollution.
The records were taken from the permanent stations at Dhobinala and Bank colony, Dimapur and therefore variations would be there from colony to colony.