GUWAHATI, Oct 31 � The Pollution Control Board, Assam (PCBA) arranged for monitoring of the air quality and noise level of major townships of the State, i.e., Silchar, Dibrugarh, Sivasagar, Tezpur, Golaghat, Nagaon and Bongaigaon besides the Metropolitan area of Guwahati city as a regular monitoring exercise being done by the Board since the last eight years.
The air quality and noise level data for different locations identified by the Board before and during Diwali day shows an overall satisfactory trend except for respirable particulate matter (RPM).
Within Guwahati, air quality was monitored at four locations � Santipur, Gopinathnagar, Bamunimaidam and Khanapara on October 15 (before Diwali) and on the Diwali day on October 25, and the three parameters NO2, SO2 and PM10 were measured.
�The average value of SO2 was found to be 6.45 �gm-3 during pre-Diwali day which increased to 12.43 �gm-3 on Diwali day. It was, however, much lower than the prescribed national standard of 80 �gm-3. The corresponding value of SO2 & NO2 for the year 2013 had been 7.52 and 12.40 �gm-3 respectively,� a PCBA official said.
However, the average PM10 value for the Guwahati on Diwali Day was found out to be approximately 200 �gm-3, which is double the prescribed national standard.
The noise level was measured at six locations in the city, and the average value of noise level was found out to be 73.4 dB(A) which is lower than 75 dB(A) prescribed for industrial zone but higher than 55 dB(A) prescribed for residential area.