Ultra-fine dust

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Ultra fine dust or ultrafine particles ( UFP ) (ultra lat. Moreover, beyond; particles lat. Pars = part) denotes the smallest fraction of the particulate matter , in turn, a portion of the total suspended particulate matter is. Ultrafine particles have an equivalent diameter of less than 0.1 micrometer (µm) (this corresponds to 100 nanometers (nm)). In contrast to nanoparticles , ultrafine particles are unintentionally introduced into the atmosphere.

Origin and Distribution

Ultrafine particles are created in particular by chemical and thermal gas phase reactions. For example, they are contained in welding fumes and diesel engine emissions. They arise when using ethanol stoves to heat interiors and when burning candles, as well as when smoking tobacco. Another source of ultrafine particles are condensation processes . The concentration of ultrafine particles is significantly increased in the immediate vicinity of roads. The number of coarse and fine particles emitted does not allow any conclusions to be drawn about the number of ultra-fine particles emitted.

Natural sources of ultra-fine particles include volcanic eruptions , forest fires and thrown up sea salt.

The propagation behavior of ultrafine particles is similar to that of gas molecules: They are transported by air currents and are distributed via diffusion processes.

meaning

Since the mass of a particle increases with the third power of its diameter, ultrafine particles contribute little to the mass concentration of fine dust even with a high number concentration. For example, at certain workplaces, ultrafine particles make up only 10 percent of the mass, but 90 percent of the number of particles in fine dust. That is why it is only possible to record them with counting measuring methods with sufficient sensitivity . This means a significantly increased expenditure on measurement technology. Ultrafine particles are often measured with measuring devices that classify particles according to electrical mobility .

Ultra-fine particles get into the human body mainly through inhalation . In the respiratory tract , they are mainly deposited by diffusion .

A 1997 publication found a better correlation with number concentration than with mass concentration with regard to respiratory diseases .

Limit value determination

In “Health Effects of Particulate Matter”, the health effects of ultra-fine dust are not assessed separately, but expressly together with fine dust in the PM 2.5 category . The WHO commission IARC (International Agency for Research on Cancer) classified the entire fine dust mixture as a class 1 carcinogen (clearly carcinogenic) in 2013. Studies by the WHO show that there is no concentration below which no harmful effect should occur. However, the WHO has not yet issued a specific recommendation to limit the number of ultrafine particles. So far, it has not been possible to quantify the benefits of mitigation measures.

Individual evidence

  1. ↑ VDI 2083 sheet 1: 2013-01 clean room technology; Particulate air cleanliness classes (Cleanroom technology; Particulate air cleanliness classes). Beuth Verlag, Berlin, p. 7.
  2. ↑ DIN EN ISO 14644-3: 2006-03 clean rooms and associated clean room areas; Part 3: Test methods (ISO 14644-3: 2005); German version EN ISO 14644-3: 2005. Beuth Verlag, Berlin, p. 6.
  3. ↑ Wolfram Birmili, Axel Pietsch, Thomas Niemeyer, Jürgen Kura, Stephan Hoffmann, Anja Daniels, Jiangyue Zhao, Jia Sun, Birgit Wehner, Alfred Wiedensohler: Occurrence and sources of ultrafine particles in the interior and in the outside air - current state of knowledge. In: Hazardous substances - cleanliness. Air . 80, No. 1/2, 2020, ISSN  0949-8036 , pp. 33-43.
  4. ↑ a b c d Vanessa Kunde: Are workplace limit values ​​for particle concentrations feasible? In: Hazardous substances - cleanliness. Air. 77, No. 10, 2017, ISSN  0949-8036 , pp. 421-426.
  5. ↑ Christoph Habarta, Marina Sysoltseva, Saskia Eckert, Ludwig Fembacher, Adela Frenzen, Janine Wolf, Richard Winterhalter, Christina Scheu, Hermann Fromme: Indoor air quality when operating ethanol stoves. In: Hazardous substances - cleanliness. Air. 78, No. 9, 2018, ISSN  0949-8036 , pp. 375-382.
  6. ↑ a b VDI 4300 sheet 12: 2020-07 (draft) measurement of indoor air pollution ; Measurement strategy and determination of ultrafine particles. Beuth Verlag, Berlin, p. 2.
  7. ↑ a b c d Christof Asbach, Ana Maria Todea: Personal exposure to ultra-fine particles in everyday life. In: Hazardous substances - cleanliness. Air. 76, No. 9, 2016, ISSN  0949-8036 , pp. 315–321.
  8. ↑ Dieter Bake, Federal Environment Agency , Department of Interior Hygiene : Ultrafine Particles in the Interior. Federal Institute for Risk Assessment , March 19, 2007, accessed on March 15, 2019 .
  9. ↑ Air quality and vehicle propulsion. VDI status report December 2018, p. 4., available at [1] (registration required)
  10. ↑ VDI 4300 sheet 12: 2020-07 (draft) measurement of indoor air pollution ; Measurement strategy and determination of ultrafine particles. Beuth Verlag, Berlin, p. 6.
  11. ↑ VDI 3867 sheet 1: 2009-09 measurement of particles in the outside air; Determination of the particle number concentration and number size distribution of aerosols; Basics (Measurement of particulate matter in ambient air; Determination of the particle number concentration and number size distribution of aerosols; Fundamentals). Beuth Verlag, Berlin, p. 2.
  12. ↑ a b Johannes Pelzer, Oliver Bischof, Willem van den Brink, Martin Fierz, Harald Gnewuch, Henna Isherwood, Markus Kasper, Andreas Knecht, Thomas Krinke, Axel Zerrath: Devices for measuring the number concentration of nanoparticles. In: Hazardous substances - cleanliness. Air. 70, No. 11/12, 2010, ISSN  0949-8036 , pp. 469-477.
  13. ↑ VDI 3867 sheet 1: 2009-09 measurement of particles in the outside air; Determination of the particle number concentration and number size distribution of aerosols; Basics (Measurement of particulate matter in ambient air; Determination of the particle number concentration and number size distribution of aerosols; Fundamentals). Beuth Verlag, Berlin, pp. 6-7.
  14. ^ Health effects of particulate matter. World Health organization, 2013, accessed June 3, 2019 .
  15. ↑ Fine dust in Switzerland 2013. Federal Commission for Air Hygiene, 2013, accessed on June 3, 2019 .
  16. ↑ Ultra-fine dust causes, health effects and research needs Ref .: WD8-3000-094 / 18, Scientific Service of the Bundestag (WD8), September 19, 2018.
  17. ↑ Marion Wichmann-Fiebig: Considerations on the legal regulation of UFP in the outside air. In: Hazardous substances - cleanliness. Air. 80, No. 1/2, 2020, ISSN  0949-8036 , pp. 44-46.