Highly selective optical fibre ammonia sensor for use in agriculture

A highly selective optical fibre sensor has been developed for the monitoring of low level atmospheric ammonia concentrations. The measuring technique employed is based on a differential optical absorption approach, which uses a broadband optical source, optical fibres for transmission and a miniature ultraviolet/visible spectrometer for detection. This novel technique for the detection of ammonia has previously been shown to be capable of monitoring concentrations as low as 1ppm without any notable cross-sensitivity issues [1]. The sensor was operated over a number of hours in-situ in an agricultural cattle enclosure and simultaneously with a commercially available ammonia sensor. Results shown herein demonstrate the effectiveness of the developed sensor to operate within the environment accurately, recording concentration levels of between 0 and 2 ppm.