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Alphasense 4-Electrode gas sensors operate using proven fuel cell technologyA4-B4-Ozone-and-NO2-3-serie

Alphasense 4-electrode air quality sensors provides OEMs with reliable sensors for use in Air Quality Networks where very low parts per billion (ppb) detection levels are required. High sensor gain, fourth electrode compensation, advanced filtering (patents pending) and electrodes optimised for long term repeatability provide the needed sensitivity, selectivity and stability. With over eight years’ experience working with air quality networks, Alphasense is your partner when developing and supplying air quality networks.

Nitrogen Dioxide and Ozone are the two critical oxidising gases when monitoring air quality. Both gases cause oxidative stress to lung cells but the regulated levels are different so it is important to separate Ozone and Nitrogen Dioxide concentrations.  The patented (and patent pending) Alphasense solution is to combine the Nitrogen Dioxide (NO2-B43F or NO2-A43F) and oxidising gas (OX-B431 or OX-A431) sensors as a pair: the NO2 sensor measures only NO2 and the difference between the two sensors gives the Ozone concentration. Gas concentrations for both O3 and NO2 are typically 20 to 200 ppb at the roadside, so good design of the sensor, housing and electronics plus intelligent data analysis are all required.

The B series sensors are designed for use in urban air fixed site networks while the A series sensors are designed for portable use and  indoor air quality networks. Since low noise electronics are needed to get full sensor performance, Alphasense offers the AFE potentiostat circuit family for the A series and ISB potentiostats for B series sensors. Use them as a benchmark during development or as the analog interface to your A/D converter.

Application notes

Download Toxic Application Notes – see application notes for full details.

Data sheets

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File Name Description Type Download Link
OX-B431 Compact, 4-electrode, low ppb Data Sheet
OX-A431 Small, 4-electrode, low ppb Data Sheet


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