Odorous gases monitoring on industrial sites and algae decomposition using Cairsens smart sensors

The appearance of natural odors sources (Sargassum beaching events) or odors generated by the human activity (integration of industrial sites in increasing urban environment and residential encroachment into previously non-resident areas) represent a major challenge for municipalities. Combined with intolerance of nuisances by residents, and/or tourists, it forces municipalities and industrial players to manage and control diffused emissions of odors in a more stringent and efficient way. Among these diffuse odors, hydrogen sulphide (H2S) and ammonia (NH3) have been identified as 2 important sources of nuisance. Beyond the olfactory discomfort, these gases may have high adverse effects on health, the severity increase with the duration and level of exposure. Consequently, they must be detected, monitored and controlled in advance. A lot of analyzers’ available in the market, including fluorescence-based detection (1) or flame photometric detector (2), provide very precise measurements at a given time and place, but such analytical devices are expensive in investment, operation & maintenance. In addition, they are not easily field transportable and usually require field calibration and A/C housing to locate them. Those instruments cannot be mass-deployed and consequently not appropriate to give a full picture of current pollution. The spatial and temporal dimensions, which define the diffused pollution, are then lost. For these reasons and because wide areas should be monitored, the management and the control of odorous emissions requires solutions composed of multiple analyzers (or accurate sensors) combined to a efficient software application. Above the nature and the quality of the algorithms of mathematical models, the reliability of results is closely linked to the number of measurement sampling points. The most representative assessment of the real situation is obtained by a network of readings over a given territory provided by a high quantity of cost-effective devices.