The key to effective environmental quality management is the ability to continuously monitor the concentrations of various pollutants, not only as they are in the ambient air but also as they leave the stack of various plants. The wet chemical methods are too time-consuming and laborious to serve the purpose. Upsets must be discovered as soon as they occur, in order to make it possible to identify the source of the problem and take immediate corrective action.
In the stack monitoring system continuous analyzers have been provided to monitor the S02 in the sulphuric aid plant stack and NOx in the three stacks of the nitric acid plants.
The SO2 monitor is based on the pulsed fluorescence technique. Pulsating ultra-violet light of wave length 190-230 mm is focused on a fluorescent chamber containing the sample stream.
ADVERTISEMENTS:
The excited SO2 molecules emit their characteristic decay radiation in the ultra-violet region which is measured by a photomultiplier tube correlated to the SO2 concentration.
The NOx analyzer is based on the chemiluminescence principle. The gas sample to be analyzed is blended with ozone. Nitric oxide reacts with ozone to form NO and the chemiluminescence multiplier tube and converted into an NO concentration.
Mobile Air Monitoring:
The mobile monitoring unit is equipped with continuous analyzers/recorders for the measurement of SO2 and NOx in the ambient air. The system is complete with shelter, power generation unit and Trailer so that it can operate independently at any place.
Image Source : media.nola.com
Plant Leaf as a Pollution Monitoring Device:
It is possible to monitor SO2 pollution with the help of sensitive plants, provided the pollutant concentration and plant response relationships are earlier established with the help of fumigation experiments and physicochemical monitoring devices.
ADVERTISEMENTS:
Sine plants constitute a living system, it is imperative to keep in view the different ecological parameters affecting the ambient and ground level concentration of SO2 and its absorption by plants.
As the magnitude of stress on plants by a pollutant is a function of ecological determinants, these must be considered for meaningful evaluation and precise correction of dose-response relationship. For short term monitoring measurements of photosynthetic leaf area, chlorophyll and ascorbic acid contents may be considered suitable.
Conclusion:
A combination of stack monitoring, mobile air monitoring, more efficient operation of plants with proper controls, and modern technology could be a useful tool in the hands of the management and the government to control air pollution and benefit society.