In an illustrative configuration, a method for monitoring air quality is disclosed. The method includes accepting analyte gas into a cell and reflecting light rays into the analyte gas repeatedly across the cell into at least one sensor. The light scattered by particulate matter in the analyte gas and amount of spectra-absorption due to presence of a gaseous chemical is then measured. Based on the determined amount of spectra-absorption and the measured scattered light the gaseous chemical is then measured.

A method for using a chemical capture system with integrated calibration having a chamber which comprises an opening and a closing member, as well as a chemical sensor to be calibrated and a photoionization sensor which are positioned in the chamber, in which method: —during a measurement step, the sensor to be calibrated and the photoionization sensor measure the gas mixture present in the chamber, defining an open interior space, so as to identify the gas mixture and —during a calibration step, the photoionization sensor generates ozone by photoionizing the dioxygen in the chamber, defining a closed interior space free of gas mixture, and the sensor to be calibrated measures the generated ozone, the difference between said measurement and a reference measurement making it possible to calibrate said sensor.

Various embodiments disclose an electronic circuit for an electrochemical gas sensor. The electronic circuit comprises a first switching element electrically coupled to a reference terminal of the electrochemical gas sensor and a ground voltage terminal. Further, the electronic circuit comprises a second switching element electrically coupled to a sensing terminal of the electrochemical gas sensor and the ground voltage terminal. In an instance in which the electrochemical gas sensor is powered OFF, the first switching element and the second switching element are configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal such that current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is powered OFF flows to the ground voltage terminal and the potential of the reference terminal and the sensing terminal remain the equal.

A system for detecting an analyte gas in an environment includes a first gas sensor, a first contaminant sensor separate and spaced from the first gas sensor, and electronic circuitry in electrical connection with the first gas sensor to determine if the analyte gas is present based on a response of the first gas sensor. The electronic circuitry is further in electrical connection with the first contaminant sensor to measure a response of the first contaminant sensor over time. The measured response of the first contaminant sensor varies with an amount of one or more contaminants to which the system has been exposed in the environment over time.

A gas sensing device includes gas sensors for generating signal samples corresponding to a concentration of a gas; a heat source for heating the gas sensors according to a first temperature profile during recovery phases and according to a second temperature profile during sense phases, a preprocessing processor for preprocessing the received signal samples; a feature extraction processor for extracting feature values from the preprocessed signal samples; a humidity processor for estimating a humidity value of the mixture of gases, including a first trained model based algorithm processor, and wherein the humidity value is based on an output of the first algorithm processor; a gas concentration processor for creating sensing results, wherein the gas concentration processor comprises a second trained model based algorithm processor, wherein the sensing results are based on output values of the second algorithm processor, and wherein the sensing results depend on the humidity value.

Methods, apparatuses and systems for calibrating gas detectors are disclosed. An example calibration apparatus may have a gas supply element configured to provide a background gaseous substance within at least a portion of the calibration apparatus, a nebulizing element configured to generate the testing gaseous substance by transforming a testing solution in conjunction with the background gaseous substance, a pressure control element configured to regulate airflow in order to maintain a constant air pressure within the at least a portion of the calibration apparatus, and a controller component in electronic communication with the gas supply element, the nebulizing element and the pressure control element.

The present invention relates to a method of calibrating a humidity sensor device, comprising the steps determining a first dew point and a first relative humidity at a first temperature in an environment by the humidity sensor device using a first calibration offset; subsequently heating the humidity sensor device, in particular, by self-heating, thereby heating the environment to a second temperature higher than the first temperature; subsequently determining a second dew point at the second temperature by the humidity sensor device; subsequently determining whether the determined second dew point differs from the determined first dew point by more than a predetermined difference; and subsequently changing the first calibration offset of the humidity sensor device by a predetermined value to obtain a second calibration offset, if it is determined that the determined second dew point differs from the determined first dew point by more than the predetermined difference.

Methods and systems are provided for pinpointing a source of degradation in a vehicle engine system. In one example, a method includes spinning an engine of a vehicle unfueled in a forward and a reverse direction, in no particular order, and recording a first intake air flow and a second intake air flow, respectively, in an intake of the engine, and where the source of degradation is indicated as a function of both the first air flow and the second air flow. In this way, the degradation of the vehicle engine system may be pinpointed as to being located in the intake manifold, the exhaust system, or the engine.

Self-calibrating a humidity sensor of an integrated humidity and temperature sensor, using the integrated heating element, and the temperature and humidity sensors, of the device, together with a firmware-based control loop running on a controller. The controller actively calculates and monitors one or both sensor output, and the slopes of the sensor outputs, in real time, while the heating element is on, and compares one or both slopes to a pre-programmed threshold, while in a programmable control loop, to then capture the appropriate relative humidity offset to apply to the device during normal operation (with the integrated heating element switched off) for correcting the relative humidity output from the device. Any singularly mounted in-system device can be calibrated, independent of external references, for in-system calibration.

A method is provided for operating a gas concentration monitoring system as well as a gas-measuring device, a central unit, a gas concentration monitoring system as well as computer program product. The safety of persons or the safety of a situation is determined with respect to at least one hazardous gas. The concentration of the gas is provided to a memory and analysis device. A measured value rating number is determined for a preset period of use. A number of instances, of the measured concentration values exceeding of a preset gas concentration limit value is input. A safety code is determined from at least one of: the measured concentration values, the measured value rating numbers and from the a total number of instances in which a gas concentration limit value was exceeded.