Abstract: An apparatus for measuring volatile organic compounds in a gas includes a sensor chamber having a housing with a gas inlet, a gas outlet, and a gas flow path from the gas inlet to the gas outlet, a set of baffles within the housing and positioned in the gas flow path, and a set of sensors within the housing and positioned in the gas flow path. Each sensor has an electrically conductive polymer whose electrical properties are dependent upon the presence of specific volatile organic compounds in the gas flow. Desirably, the set of baffles and the set of sensors are cooperatively positioned such that the time for gas to flow from the gas inlet to each of the sensors is substantially the same. The apparatus further includes a pump that removes the gas from the gas outlet of the housing, and an electronic circuit that measures the electrical properties of each of the sensors.

Abstract: A plurality of sensor units are distributed over an area and communicate via a network with a central monitoring unit. The sensor units include sensor arrays that provide them with raw data in response to the presence of selected compounds in the ambient fluid. The raw sensor data is then processed to compute a local profile, which (a) illustrates a change in the compounds in the fluid from their normal state (change detection) , (b) indicates the presence and total concentration of foreign compounds in the fluid (presence detection), or (c) details the composition and concentrations of defined classes or individual species of compounds in the fluid (composition detection). The local profiles from the individual sensor units are then used to compute a spatial and temporal map for the compounds in the fluid.