“At NPL we have an interest in ammonia measurements following our participation in a European project called Metrology for Ammonia in Ambient Air (MetNH3) where we developed stable primary standard gas mixtures in cylinders to validate certain technologies to measure ammonia. This included using our exposure chamber to traceably measure the ammonia diffusive sampling rates of all the common low cost sensors on the market to improve the accuracy of ambient monitoring, alongside assessing pumped sampling (the unofficial “reference” method).
We collaborated with a US manufacturer to reduce the undesirable effects of water cross interference in a cavity ringdown spectrometer (CRDS), and participated in a field campaign at the Centre for Ecology and Hydrology, which included an open path spectrometer. We have subsequently developed a controlled release facility for ammonia and are working with an SME developing a laser dispersion spectrometer for open path measurements of ammonia through Analysis for Innovators (A4I).
We would also be interested in being involved in projects that are trying to map agricultural releases of ammonia using the latest technologies. For example, extractive measurements require careful sampling strategies but open path measurements can have issues to do with the spectroscopic background.”
Dr Nick Martin
National Physical Laboratory