A long term portable gas detecting and monitoring apparatus includes a case having a continuous sidewall including a first end closed by a first end cap, and a second end closed by a second end cap connected sealably and removably to the continuous sidewall. The continuous sidewall is triangular between the closed end and the open having three sides and three corners, two of the three sides being straight and equal in length, one of the three sides being rounded, and each of the three corners being rounded. A long term gas detection and monitoring unit mounted in the case includes gas, and temperature and humidity sensors in communication with an ambient atmosphere outside the case, a data processor operatively connected to the sensors, data storage, an information display viewable through the case, and a calibration unit for calibrating the gas sensor to a predetermined gas concentration measured by the gas sensors.

Embodiments of a gas detector with a first gas sensor having a first gas specificity and a first response time and a second gas sensor having a second gas specificity and a second response time. The first gas specificity is different than the second gas specificity, the first response time is different than the second response time, or both the first gas specificity and the first response time are different than the second gas specificity and the second response time. A readout and analysis circuit is coupled to the first and second gas sensors to read and analyze data from the first and second gas sensors, and a control circuit is coupled to the readout and analysis circuit and to the first and second gas sensors to execute logic that operates the first gas sensor, the second gas sensor, or both the first and second gas sensors.

A system for analysis of at least one analyte gas present in an insulating fluid of an electrical transformer includes a gas sensor in operational contact with at least one analyte gas from an insulating fluid to provide multiple responses from the sensor. One or more processors are configured to receive the multiple responses during exposure of the sensor to the analyte gas from the insulating fluid representative of a concentration of the analyte gas present in the insulating fluid. The processors are configured to select one or more responses of the multiple responses that provide rejection of interfering gases, resolution between gases, improved low detection range of the analyte gas, improved high detection range of the analyte gas, improved response linearity of the analyte gas, improved dynamic range of measurements of the analyte gas, or one or more combinations thereof compared to non-selected responses from the sensor.

Disclosed is an air-quality detection apparatus including a casing body including a bottom and a side wall, a first printed circuit board (PCB) disposed horizontally above the bottom, a second PCB disposed horizontally in a first region above the first PCB, a CO.sub.2 sensor mounted on the second PCB, a volatile organic compound (VOC) sensor mounted in a second region on the first PCB that is closer to the side wall than the first region, a third PCB, which is disposed horizontally at a position spaced further upwards apart from the bottom than the first PCB and at least a portion of which is disposed in a third region that does not overlap the first PCB when the bottom is viewed from above, a fourth PCB disposed horizontally above the second PCB and the third PCB, and a dust sensor mounted on the fourth PCB.

An air-quality detection apparatus is disclosed. The air-quality detection apparatus includes a casing body including a bottom and a side wall extending upwards from the circumference of the bottom, a first printed circuit board (PCB) disposed horizontally above the bottom, a temperature/humidity sensor mounted on the bottom surface of the first PCB, a second PCB disposed horizontally above the first PCB, and a CO.sub.2 sensor mounted on the second PCB.

A sensor module has a first sensor element and a second sensor element. The first sensor element and the second sensor element are accommodated in a common housing of the sensor module. The sensor module includes a conductor structure that comprises an electrode structure and a separate connection structure. The connection structure is connected in an electrically conductive manner to the first sensor element and the electrode structure is allocated to the second sensor element.

A method and an analyzer for detecting impurities in refrigerant (e.g. methyl chloride (R40) or Chlorodifiuoromethane (R22)), wherein the refrigerant analyzer (12) includes a first sensing device (16), preferably a non-dispersive infrared sensor (NDIR), in flow communication with a second sensing device (18), preferably an electrochemical sensor. The first sensing device is configured to determine a first characteristic of a refrigerant (e.g. absorbance in the IR range), and the second sensing device is configured to detect a second characteristic of the refrigerant (e.g. concentration in ppmv). Preferably, the refrigerant analyzer is a part of a system for detecting impurities (10) and further preferably it comprises flow regulators (20), a scrubber (24) and a processor (22). The scrubber is preferably in flow communication with the first sensing device and it preferably comprises a packing material comprising alumina (Al2O3, aluminum oxide).

A gas detecting device is disclosed and comprises a main body, a suspended particle sensing module and a gas sensing module, wherein the main body includes a first sensing area and a second sensing area. A suspended particle sensing module disposed within the first sensing area includes an irradiating mechanism, a first gas transporting actuator, a laser device and a light sensing device. The first gas transporting actuator transmits air to the first sensing area, the suspended particles in the air is irradiated by the laser beam emitted from the laser device to generate scattered light spots for the light sensing device to detect the suspended particles. The gas sensing module disposed within the second sensing area includes a gas sensor and a second gas transporting actuator. The second gas transporting actuator transmits air to the second sensing area, and the gas sensing device detects a gas composition contained in the air.

The disclosure involves multi-source data assimilation. According to an embodiment, first data associated with an indication of environmental quality in a first region is obtained, and second data associated with an indication of environmental quality in a second region is obtained. The first data is of a higher quality than the second data according to a predetermined criterion. The second data is calibrated according to a relationship between the first and second data in an overlap of the first and second regions. Third data associated with an indication of environmental quality in a third region is determined based on the first data and the calibrated second data, wherein the third region comprises at least the first and second regions.

A multi-component gas analysis system includes a spectrometric analysis device configured to obtain ratio of each of first components in a multi-component gas based on an absorption spectrum of light that has transmitted through the multi-component gas; a density measurement device configured to measure a first density of the multi-component gas; and a calculation device configured to calculate a ratio of each of second components in the multi-component gas using the ratio of each of the first components obtained by the spectrometric analysis device and the first density measured by the density measurement device, the second components being components that cannot be obtained by the spectrometric analysis device.