BS EN 15853:2010 pdf download
BS EN 15853:2010 pdf download.Ambient air quality 一Standard method for the determination of mercury deposition.
3.1.10
expanded uncertainty
product of a combined standard measurement uncertainty and a factor larger than the number one
NOTE 1 The factor depends the type of probability distribution of the output quantity ii a measurement model and on the selected coverage probabEty.
NOTE 2 The term actor in this definition refers to a coverage (actor.
NOTE 3 Errpanded measurement uncertaty termed overal uncertainty in paragraph 5 of Recommendation INC-i (1980) Isee the GUM) and simply uncertaalty” in IEC documents (ISO1IEC Guide 99 (VIM)J,
NOTE 4 For the purpose of this document the expanded uncertainty is the combined standard uncertainty multiplied by a coverage factor t = 2 resulting In an witrval with a level of confidence of 95 %.
3.1.11
field blank
artificial sample (e.g. de-tonised water) taken through the same procedure as the pt’ecip.tation sample, except that this has not been exposed to precipitation
NOTE It Is transported to the sampling site, mounted in the sampling unit, returned to the laboratory and worked up m the same way as the deposition sample.
3.1.12
laboratory blank
artificial sample (e.g de-ionised water) taken through the same procedure in the laboratory as the precipitation sample, worked up in the same way as the deposition sample
3.1.13
measurement uncertainty
non-negative parameter characterizing the dispersion of the quantity values being attflbuted to a measurand, based on the information used
NOTE 1 Measurement uncertainly w’eckides components arising from systematic effects, such as components associated with corrections and the assigned quantity values of measurement standards, as wel as the definitional uncertainty. Sometimes estimated systematic effects are not corrected lot but, wstead, associated measurement uncertainty components are wioorporated
NOTE 2 The parameter may be. for example, a standard deviation caSed standard measurement uncertainty (or a specified multiple of it), or the half-width of an iterval, having a stated coverage probebility
LISOIIEC Guide 99:2007 (VIM))
3.1.14
precipitation
rain, snow, sleet, snow pellets (grauper) and hail
3.1.15
reagent blank
artificial sample (e.g. de4onised water) pocessed through the analytical measurement steps
3.1.16
wet deposition
sum of depositions of sedimenting wet particles and droplets
NOTE Wet particles and droplets in the atmosphere undergo the process of scavenging of any gases and/u particles. Wet deposition isa part of the atmospheric deposition.
3.1.17
wet-only collector
equipment to collect wet deposition, typically a funnel-bottle combination
4 Principle of mercury deposition determinations
Atmospheric deposition is defw’ied as the sum of the depositions of sed.menting particles, non-sedimenting particles and gases. Total atmospheric deposition is the sum of dry deposition and wet deposition. Bulk deposition is the sedirneriting part of the atmospheric deposition.
There Is no method available to determine total atmospheric deposition In one measurement The determination of the dry deposition requires miaometeorological measurements, taking into account the turbulent atmospheric transport processes. Wet deposition and bulk deposition, however, can be estimated using suitable collectors.
This standard describes methods to determine wet deposition and bulk deposition of mercury using wet-only- and bulk collectors.
The wet-only collector is designed to collect sedimenting water containing wet particles only. while the bulk collector is designed to collect all sedimenting wet and dry particles. However, since the deposition process is affected by various factors. e.g. wind speed, temperature, vegetation, surface type, etc., the wet-only collector wil not catch all sedimenting wet particles while some sedimenting dry particles. non-sedimenting particles and gases will be collected. Also, the bulk collector will not catch all sedimenting particles while some nonsedimenting particles and gases wl be collected.
The method is divided into two main parts:
a) camping of precipitation in the field;
b) mercury analysis in the laboratory.
The precipitation sample is stabilized with hydrochloric acid and transferred to the laboratory in the collection vessel, Mercury in the precipitation sample is oxidised using bromine monochloride Mercury is analysed either by CVAAS or CVAFS detection.
5 Siting requirements for mercury deposition determinations
The lollowing guidelines shall be met as far as practicable (Annex 111.11 of Directive 2004/107/EC [10)):
a) The site chosen for sampling arid measurements shall be representative of a larger area. The size of this area is determined by site characteristic (urban, industrial or rural) and the variability of the air and precipitation quality.
b) The collector shall as far as possd,le not be exposed to areas where unrepresentative strong winds occur like shores. cliffs and top of hills, but it shall also not be shattered by tall trees or buildings.
