A Simple, Controllable, Non-Point Source of Gaseous Ammonia, for Use in Field Experiments

• Published in: Environmental technology 1999-03, Vol.20 (3), p.239-247
• Main Authors: Kim, J. H., Williams, A. G., Phillips, V. R.
• Format: Article
• Language: English
• Subjects: Ammonia (NH3); Applied sciences; atmosphere; Atmospheric pollution; calibration; Dispersed sources and other; emission; Exact sciences and technology; Pollution; Pollution sources. Measurement results; source
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/09593332008616814

A type of controllable non-point source of gaseous NH 3 has been developed, which is simpler, more reliable and more versatile in use than earlier types of source. The source is based on a suitable length of a suitable type of permeable plastic tubing, to which pure NH 3 gas is supplied at a suitable pressure. Once steady state is achieved, the emission rate of NH 3 from the tubing equals the permeation rate through the tubing wall: the rate is continuously monitored via the rate of weight loss from the cylinder supplying the NH 3 gas, mounted on a suitable recording electronic balance. A simple apparatus is described for determining permeation rates of NH 3 through samples of different types of tubing, as are two examples of applying the source in field experiments. In the first example, a two-dimensional source was constructed inside the bottom of a clean, dry above-ground cylindrical slurry store (6 m diameter) and used to test passive ammonia flux samplers as a means of measuring NH 3 emission rates from such stores when containing slurry. In the second example, a two-dimensional source was constructed on the floor of a full-scale simulation of part of a cattle house (naturally-ventilated), and used to test passive ammonia flux samplers as a means of measuring NH 3 emission rates from such houses when cattle are in residence.