Devices, systems, and method for monitoring air quality are provided. Digital out-of-home advertising display units are located within a geographic area. The units include an electronic display for displaying advertising images located at a housing, an open loop pathway for ambient air extending between an ingestion and exhaustion area of the housing. An air quality monitoring device located along the open loop pathway includes comprising sensor(s) for measuring characteristics of encountered gasses which are electronically communicated by a network connectivity device to a monitoring station. The monitoring station generates visual representations of the received measurements, at least one of which summarizes the measurements from multiple ones of the units.

Methods and systems for predicting gas concentration values are described, which may include predictions based on gas measurement information received from a gas sensor and gas sensor response information for the gas sensor. The gas sensor response information which may be in the form of a sigmoid function. In some embodiments, the predicted gas concentration values may be generated by predicting an asymptotic value of the gas measurement information based on a rate of change of the concentration of the gas and the gas sensor response information.

A measurement apparatus includes: a number concentration measurement device configured to measure a number concentration of particles in a air; a humidity measurement device configured to measure a humidity of the air; and a air concentration measurement device configured to measure a concentration of a specific air in the air, wherein a mass concentration of the particles in the air is calculated based on a measured number concentration, a measured humidity, a measured concentration of the specific air, and a predetermined correlation between the number concentration, the humidity, and the concentration of the specific air, and the mass concentration of the particles in the air.

A sulfur oxide detection system includes an element part which includes a sensor cell and a diffusion regulating layer. The sensor cell includes a solid electrolyte layer, a first electrode arranged, and a second electrode. The sulfur oxide detection system also includes a voltage application circuit configured to apply a voltage to the sensor cell so that a potential of the second electrode becomes higher than a potential of the first electrode, and a current detection circuit configured to detect a current flowing between the first electrode and the second electrode. The sulfur oxide detection system further includes a controller coupled with the voltage application circuit and the current detection circuit, and configured to estimate a sulfur oxide concentration in a gas to which the first electrode is exposed by way of the diffusion layer.

The present invention relates to a gas detector cell and cell unit for optical detection of a predetermined gas, the cell being provided with optical means for investigating a gas sample present in the cell. The cell is constituted by a volume enclosed in a container, at least part of the container wall being constituted by a membrane, the membrane being provided with openings allowing diffusion of gas therethrough, and the membrane openings being provided with a catalyst for converting the gas diffusing therethrough to said predetermined gas.

A method for determining emissions in an exhaust plume (11) produced by a combustion engine of a vessel (10) during cruise of the vessel (10), said emissions including the presence or concentration of carbon dioxide (CO.sub.2) and/or sulphur dioxide (SO.sub.2) and/or the count and size of particles. The position and distribution of the exhaust plume (11) is determined or estimated on the basis of the position, bearing and speed of the vessel (10) and further on the basis of meteorological data, such as wind direction and speed. An unmanned aerial vehicle (UAV) (12), i.e. a so-called drone, is controlled to fly through the 10 plume (11) to make measurements of exhaust emissions of the vessel (10).

A wearable device with an air quality sensor, the wearable device, comprising a housing enclosing an electronic board, a display arrangement, a battery, the housing lodging a cavity with an internal area, the cavity containing an air quality sensor in the internal area, the cavity being delimited by a cavity wall and by a membrane, the membrane having an inner wall oriented toward the cavity internal area and an outer wall opposed to the inner wall, the internal area of the cavity being in fluid communication with the ambient air through the membrane, the membrane being permeable to air and substantially not permeable to water.

A system and method for determining impurities in a beverage grade gas such as CO.sub.2 or N.sub.2 relies on a coupling of FTIR analysis and UV fluorescence detection. Conversion of reduced sulphur present in some impurities to SO.sub.2 can be conducted using a furnace. In some cases, CO.sub.2 % also is determined.

A gas sensor is revealed, and the gas sensor comprises a sapphire substrate. An epitaxial oxide sensing layer is disposed on the sapphire substrate and formed by a thin film of single-crystalline gallium oxide series grown by using metal-organic chemical vapor deposition. The material of epitaxial oxide sensing layer include oxygen, gallium, and zinc. Two electrodes are disposed on a portion of the epitaxial oxide sensing layer. When the epitaxial oxide sensing layer senses a gas, a current will be generated and change the resistance. The two electrodes thereon receive the resistance. According to the change of the resistance, the concentration of the gas can be deduced. A heating element is further disposed below the sapphire substrate for providing the temperature required for sensing.

The present invention discloses an energy efficient air purification system 100 for purifying a complex polluted environmental air condition. The air purification system 100 comprises a plurality of air pollution monitoring units MU.sub.1, MU.sub.2, MU.sub.3, MU.sub.4 . . . MUN.sub.N which are installed at distant locations, a plurality of air purification units PU.sub.1, PU.sub.2, PU.sub.3, PU.sub.4 . . . PU.sub.N which are installed at distant locations and an automated control unit 500. The air pollution monitoring units are adapted to monitor the quality of the air in their surroundings. Upon such monitoring, the air pollution monitoring units are adapted to communicate the air quality data to the automated control unit 500. The said automated control unit 500 is adapted to analyze the air quality data and on basis of such analysis, the automated control unit 500 further instructs the air purification units for further action.