Smell hour

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An odor hour is a unit of measurement for assessing odor immissions . The odor hour is defined as follows: If recognizable odors are detected within an hour in a certain partial period (generally one tenth of an hour) , an odor hour is present, i.e. the entire hour is counted as an hour with odor exposure. The relative number of odor hours (number of odor hours in relation to the total number of hours) is the measurand of the immission and is used to evaluate the permissible odor immission for different areas (e.g. residential areas).

background

There are no suitable chemical-physical measurement methods for measuring odor nuisance . Psychophysical procedures, i.e. the direct determination of the odor threshold by humans, cannot be replaced. Among other things, the meanwhile withdrawn VDI guideline 3881 Part 1 "Olfactometry - Odor threshold determination - Basics" gave an overview of suitable procedures for approval procedures. These can now be found in the standard DIN EN 13725 "Air quality - determination of odor concentration with dynamic olfactometry".

Since many individual short-term odor effects can give the individual impression that there is a continuous smell, a standardization of the procedure for determining the duration and persistence of odor immissions was necessary. The term odor hour was defined for this.

When determining an odor , it is not the perception threshold that it smells, as is the case in olfactometry , but the detection threshold that it smells like.

Typical odor emitters are agriculture, waste disposal, production plants of companies in the chemical and paper industry, refineries and the food and beverage industry.

How to determine

An odor hour is determined as part of the approval process or in the event of resident complaints by means of inspections by trained testers - also known as sniffer teams in the jargon (cf. also the historical coffee scouts ). The examiners must meet certain physiological and psychological requirements. As part of an inspection, an inspector stands at locations to be determined beforehand - measuring point in a previously defined grid - and uses one of the two methods listed below for an individual measurement at a location:

  1. The examiner takes an olfactory sample every ten seconds for a period of ten minutes. The respective result is recorded in the form of a yes / no statement stating the type of odor. The odor time portion is the ratio of the positively assessed odor samples to their total number. Odor perception outside the ten-second cycle should not be taken into account.
  2. The examiner assesses each breath and starts or ends the time recording with the on or off of the odor perception. The odor time component is the ratio of the total duration of odor perception to the measurement time interval. This method suggests that the measurement time interval is assessed continuously; in fact, however, there is only an assessment of all breaths in the measurement period. Special data recording devices are required for this measurement process, and the data obtained can then be read immediately by EDP.

If the determined odor time portion of the individual measurement exceeds a specified value, this individual measurement is assessed as an odor hour. The North Rhine-Westphalia odor emission guideline sets a value of ten percent for this.

An olfactory hour is not only a measurement result , but also represents an evaluation. The definition criticizes that no information on measurement uncertainty is possible and that if the odor perception is ambiguous, a small number of breaths is sufficient to make the result count as straight or not to be counted.

literature

  • VDI 3940 Part 1: 2006-02 Determination of odorous substance immissions through inspections; Determination of the immission frequency of recognizable odors; Grid measurement (Measurement of odor impact by field inspection; Measurement of the impact frequency of recognizable odors; Grid measurement). Beuth Verlag, Berlin. ( Table of contents , abstract ).

Web links

Wiktionary: Smell lesson  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ LANUV: Dispersion calculation for odorous substances ( Memento of February 24, 2016 in the Internet Archive )
  2. ↑ a b Determination and assessment of odor immissions (odor immissions guideline - GIRL -), RdErl. D. Ministry of the Environment and Nature Conservation, Agriculture and Consumer Protection - V-3-8851.4.4 - dated November 5, 2009, Section 4.4.7
  3. ^ A b c Jürgen Hellbrück, Manfred Fischer: Environmental Psychology: A Textbook . Hogrefe Verlag, 1999, ISBN 978-3-8409-0621-3 , pp. 152 ( google.com [accessed February 16, 2016]).
  4. ↑ VDI guideline: VDI 3881 sheet 1 olfactometry - odor threshold determination - basics. Association of German Engineers, accessed on February 17, 2016 .
  5. ↑ Eckehard Koch: On the history of the determination and evaluation of odor immissions . In: Air cleanliness commission in the VDI and DIN standards committee KRdL (ed.): Odors in the environment . VDI reports 2195, 2013, ISBN 978-3-18-092195-2 , pp. 1–14.
  6. ↑ a b c Ralf Both: Basics of the method of the grid and flag inspection according to VDI 3940 and odor immissions guideline . In: Air cleanliness commission in the VDI and DIN standards committee KRdL (ed.): Odors in the environment . VDI reports 1373, 1998, ISBN 3-18-091373-8 , pp. 273-286.
  7. ↑ Christoph Mannebeck: The future of the determination of odor immissions by grid inspections according to VDI 3940 Part 1 in the age of Web 2.0 . Hazardous substances - keeping the air clean , Volume 71 (2011) 10, pp. 455–458.
  8. ↑ VDI 3940 sheet 1: 2006-02 Determination of odorous substance immissions through inspections; Determination of the immission frequency of recognizable odors; Grid measurement (Measurement of odor impact by field inspection; Measurement of the impact frequency of recognizable odors; Grid measurement). Beuth Verlag, Berlin. P. 10.
  9. ↑ Andreas Sowa, Stephan Schirz: Odors from animal husbandry - comparison of different evaluation methods . Hazardous substances - keeping the air clean, Volume 61 (2001) 6, pp. 127–132.
  10. ↑ a b VDI 3940 sheet 1: 2006-02 Determination of odorous substance immissions through inspections; Determination of the immission frequency of recognizable odors; Grid measurement (Measurement of odor impact by field inspection; Measurement of the impact frequency of recognizable odors; Grid measurement). Beuth Verlag, Berlin. P. 15.
  11. ↑ Martin Kamp: New guideline VDI 3894 replaces guideline series VDI 3471 . Agricultural and Environmental Law, No. 5, 2013, pages 294–300.
  12. ↑ Werner-Jürgen Kost, Claus-Jürgen Richter: Determination of the odor immissions (grid measurement) according to VDI 3940 Part 1 . Hazardous substances - keeping the air clean, Volume 69 (2009) 7/8, pp. 315-317.