BS EN 17346:2020 pdf free.Ambient air – Standard method for the determination of the concentration of ammonia using diffusive samplers.
BS EN 17346 Details of these approaches shall be documented. Samplers can be provided with manufacturer measured sampling rates. Samplers in networks often have on-going measurements of sampling rates. Users can calculate a locally derived sampling rate.Sampling rates are also documented in literature [see [36], and Annex D].The sampling rate in the field is a function of local meteorology. Samplers can be deployed with protective shelters to minimize meteorological influences. When doing so, the user shall apply a suitable protocol to ensure a consistent approach for all samplers. Ideally, the effect of the shelter on the sampler performance should be characterized. 4.2 Implementation Samplers shall be sealed and stored under cool conditions, for example at temperatures between 0。C and 4。C, in the dark, in order to minimize any undesired reactions before and after deployment. After deployment, samplers shall be analysed as soon as possible, according to manufacturer’s specifications. Disposable gloves shall be worn at all times, including during deployment in the field. This serves to protect the samples from contamination by contact with the skin. It is also advised to avoid breathing directly on the samples, as exhaled breath contains NH3.Since there are different sampler designs, each common sampler type is briefly described below. 4.3 Tube-type samplers
The tube-type samplers are hollow cylindrical tubes oriented vertically. A cap at the top end holds in place either a cellulose filter paper, glass fibre filter or stainless steel grid, which is coated with a sorbent that collects the gas of interest. This type of sampler is characterized by a high length to cross sectional
area ratio [15, 32]. To collect NH3, sorbents used include citric, phosphoric, phosphorous, sulphuric and tartaric acid [38]. The analysis is carried out using various methods including ion chromatography,flow injection analysis with detection of conductivity and spectrophotometry.BS EN 17346 pdf downlaod.