LBL's accurate CO sensor
15 Jan 2000
Researchers at the Lawrence Berkeley Laboratory have developed a lightweight, low-cost carbon monoxide sensor that, they claim, is three times as accurate as current personal CO sensors. The device relies on diffusion processes to convey ambient gases to a palladium/molybdenum sensor.
The sensor is mounted at the base of a 2cm-long polystyrene diffusion tube, which ensures the gases flow at a constant rate. The sensor gradually changes colour from yellow to blue, in proportion to the concentration of CO in the air. A simple reading from a lab spectrophotometer will then show exactly how much the colour has changed and therefore precisely the amount of CO the sensor has absorbed.
The device can be used as an `occupational dosometer', clipped to a person's clothing to show how much CO they have been exposed to over a certain period of time, or as a `residential passive sampler', to show the average exposure in a home or office over a week.
There is a definite need for an accurate, small CO sensor, says Michael Apte of the LBL environmental energy technology division. The number of accidental CO poisonings every year is difficult to estimate as the symptoms of low-level cumulative exposure are very similar to an attack of flu; and current sampling methods rely on cumbersome and expensive equipment.
