Contrary to popular perception that air pollution is going up in the State, two of the major air pollution parameters — nitrogen dioxide from vehicle emissions and sulphur dioxide from industrial emissions — were well within the permissible limits in the State during the past five years.
This forms part of the findings in the Ambient Air Quality monitoring report compiled by the Kerala State Pollution Control Board (PCB), between 2011 and 2015
The report also indicates that Respirable Suspended Particulate Matter (the microscopic liquid or solid matter found suspended in the atmosphere) of sizes between 2.5 micron and 10 micron had recorded a dip in 2015, though it had gone up by over 100 per cent of the permissible levels in 2013 and 2014 in some stations.
Air quality data
The air quality data, to be released by the PCB on June 5, assumes significance in the wake of the National Green Tribunal (NGT) imposing a ban on diesel vehicles. In its landmark judgement, the NGT had held that no “diesel vehicle with the capacity of 2000 cc and above, except Public Transport and Local Authority Vehicle” shall be registered in the State and “all the diesel vehicles, whether light or heavy, which are more than 10 years old, shall not be permitted to ply on the road in the major cities such as Thiruvananthapuram, Kollam, Kochi, Thrissur, Kozhikode and Kannur.”
The Central Pollution Control Board had fixed the permissible concentration of sulphur dioxide as 50 micron/normal metre cube in Ambient Air for industrial, residential, rural, and other areas. The upper limit for nitrogen dioxide was fixed as 40 micron/normal metre cube. Barring Veli in Thiruvananthapuram, the sulphur dioxide level was found to be relatively lower in all the monitored stations. The highest value (17.37 micron/normal metre cube) in five years was obtained in 2015 from Veli.
Relatively high areas
The nitrogen dioxide emissions were relatively high in the air samples near SMV School, Murinjapalam, and Pettah in Thiruvananthapuram district all these years and 2015 proved to be the worst year as higher values were recorded from all these stations.
The PCB has compiled the data after analysing the air data from 24 stations set between Thiruvananthapuram and Kanhangad.
The Lawyers Environmental Awareness Forum, the petitioner in the case before the tribunal, had pointed out that lorries and trucks, which are more than 10 years old, were the key culprits in the rising air pollution levels of the State. The poorly-maintained buses of the Kerala State Road Transport Corporation were adding deadly gases to the atmosphere, they pointed out, while pleading for the ban on polluting vehicles.
