BS EN 16868:2019 pdf free.Ambient air – Sampling and analysis of airbone pollen grains and fungal spores for networks related to allergy – Volumetric Hirst method.
3.1 measurement accuracy accuracy of measurement accuracy closeness of agreement between a measured quantity value and a true quantity value of a measurand Note 1 to entry: The concept ‘measurement accuracy’ is not a quantity and is not given a numerical quantity value. A measurement is said to be more accurate when it offers a smaller measurement error.
Note 2 to entry: The term “measurement accuracy” should not be used for measurement trueness and the term “measurement precision” should not be used for ‘measurement accuracy’, which, however, is related to both these concepts. Note 3 to entry: Measurement accuracy is sometimes understood as closeness of agreement between measured quantity values that are being attributed to the measurand. 3.15 microscope optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye 3.16  objectives optics (in a telescope, microscope, camera, or other optical system), the lens or combination of lenses, that first receive the rays from the object and form the image in the focal plane of the eyepiece, as in a microscope, or on a plate or screen as in a camera Note 1 to entry: Also called object glass, object lens, objective lens. 3.17 orifice opening or aperture, as of a tube or pipe; a mouthpiece with a slot-like opening on the side of the trap.3.21 repeatability condition of measurement repeatability condition condition of measurement, out of a set of conditions that includes the same measurement procedure, same operators, same measuring system, same operating conditions and same location, and replicate measurements on the same or similar objects over a short period of time Note 1 to entry: A condition of measurement is a repeatability condition only with respect to a specified set of repeatability conditions. Note 2 to entry: In chemistry, the term “intra-serial precision condition of measurement” is sometimes used to designate this concept.BS EN 16868 pdf download.