Ammonia

[SAQN admin]

Ammonia was a very popular topic of conversation at our launch. Some of the questions raised were:

NH3 emissions from Ag activities are an issue and high on DEFRA’s agenda. Livestock sheds do contribute to those emissions but there is limited (if no) understanding / inventory of those emissions and building permit regulations, as set today, do not allow much control over them. In-shed NH3 generation can also be detrimental to animal welfare and growth (e.g. poultry). Could we imagine a project/ POC looking at measuring/ monitoring/ mapping actual NH3 emissions from chicken/ pigs sheds across the UK and developing chemistry-based mitigation solutions? Results could support the development of new policies and regulations. It would also be an opportunity to validate new technologies (reliable NH3 sensing, cost-effective NH3 abatement) with the potential to take them to commercialisation.

Evaluation of ammonia monitoring, ambient vs. long path vs satellite
Build on the STFC Food Network project. Evaluate the long path monitoring technique against traditional ambient monitoring and satellite data retrieval.
Allowing us to provide best policy advice on how to measure effectiveness of interventions to reduce ammonia emissions from slurry pools, fields or farm-wide levels.

STFC capability could support the development of vertical profilers for addition to, e.g., urban supersites and FAAM, to measure vertical concentration profiles, incl. for ammonia. These are needed to link groundbased and EO measurements, improve EO retrievals and to assess chemistry and transport models.

There are many groups developing systems for measuring NH3. STFC could support this community with information on sensor technology. SAQN+ could support some a discussion forum and information exchange.

[SAQN admin]

From Jim Mills, EIC
On the matter of ammonia sensing/monitoring. As Ammonia is notoriously difficult to transport in sample lines without significant losses and memory effects due to its “sticky” nature it may be worth considering open path optical sensing. Tuneable Diode Laser (TDL) systems can measure down to around 50-100ppb with path-lengths of just 10m (5m physically between transmitter and detector) The atmosphere inside animal houses could be monitored directly without the need for complex multi-point heated sampling systems. The longer the path-length (up to around 100m) the better the D.L.
If anyone is interested, I would be happy to discuss further and possibly help facilitate a project.

[SAQN admin]

Kevin Smith, STFC

Hi Jim,
There are two groups within STFC’s RAL Space that are interested in developing ammonia emissions monitoring systems. One idea has been proposed for STFC Challenge Led Applied Systems (CLASP) funding and would develop a prototype instrument using passive microwave technology for measurements in animal houses or over fields. The other is a system that would allow eddy covariance measurements for identifying sources and sinks of ammonia in the environment. This would use an STFC-patented technique called laser dispersion spectroscopy enabling measurements to be made with 1ppb sensitivity at 10Hz. I’d be very happy to put you in touch with the scientists involved if useful.

[SAQN admin]

“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

e-mail: nick.martin@npl.co.uk
Web: http://www.npl.co.uk

[Author]

Posts