Precursor gas

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A precursor gas ( English precursor gas , also in the German often called precursor gas referred to) is a gaseous starting material , by chemical reactions with the constituents of air particulate forms, or other pollutants, and so in addition to exhaust gases and tire wear contributes to a significant extent to their advent.

Pollutants present in the air can combine with precursor gases to form secondary pollutant particles. This connection can be made mechanically ( nucleation ) or chemically ( condensation ). The pollutants emitted directly from a source result in other, new pollutant particles. The origin of the pollutants measured in the breath can therefore no longer be traced directly. Precursor gases can be transported over greater distances. If there is exposure to particulate matter or ground-level ozone , local measures such as urban driving bans therefore have little effect on the precursor gases.

Synonyms for precursor gases are precursor source, precursor substances and precursor substances .

Precursor gases of fine dust

species

The most important species of particulate matter precursor gases are

Since methane is a precursor to ground-level ozone, it is often not VOCs but NMVOCs (non methane volatile organic compounds: volatile organic compounds with the exception of methane) that are listed as precursor gas for fine dust.

The precursor gases relevant for the formation of fine dust are mainly anthropogenic .

Emergence

  • Sulfur dioxide and nitrogen oxides arise from combustion processes.
  • Ammonia comes from agriculture (fertilization and animal husbandry).
  • Volatile hydrocarbons are produced in forests and crops, but also in combustion processes.

The Deutsche Umwelthilfe (DUH) estimates that two thirds of the fine dust is formed from precursor gases. In Western Europe, ammonium nitrates from the reaction of ammonia and nitric acid would be the main source of particulate matter in urban air.

Precursor gases of ground-level ozone

species

Emergence

  • Around half of the nitrogen oxides come from the traffic sector, primarily road traffic, the remaining proportion mainly from combustion systems.
  • Around half of the volatile organic substances are released when using solvents.

Precursor gases of the ozone layer in higher air layers

species

  • Nitrogen oxides (NO x )
  • Carbon monoxide (CO)
  • Volatile organic compounds

Emergence

Ozone precursor gas emissions are strongly influenced by human activities.

Individual evidence

  1. ↑ Fine dust PM10, questions and answers on properties, emissions, immissions, effects and measures , Federal Office for the Environment (FOEN), November 7, 2006, p. 39
  2. ^ Education Server , Secondary Aerosols , accessed February 9, 2016
  3. ^ Informationsdienst Wissenschaft (idw), Darmstadt scientists: "Measures against fine dust are insufficient" , April 4, 2006
  4. ↑ Fine dust in Germany , by Alfred Wiedensohler , Gerald Spindler, Birgit Wehner, Wolfram Birmili, Thomas Gnauk, Erika Brüggemann and Jost Heintzenberg, Leibniz Institute for Tropospheric Research (IfT), p. 38
  5. ↑ Short-lived climate-effective pollutants , Institute for Advanced Sustainability Studies (Potsdam Sustainability Institute, IASS), p. 19
  6. ↑ promet , Volume 23, Issue 3/4, German Weather Service (DWD)
  7. ^ Health portal Austria, fine dust: Air pollutant number 1 , March 2nd, 2015
  8. ↑ Fine dust, a health policy challenge , Pneumology 2005; 59: 704-714
  9. ^ Hessian state parliament, health hazard through ultra-fine particle emissions from aircraft engines in the vicinity of Frankfurt Airport , small inquiry from Bündnis 90 / Die Grünen from October 25, 2013
  10. ↑ Max Planck Society, More dead from air pollution , September 16, 2015
  11. ^ Leibniz Association, Environmental Research for Political Practice , February 2005
  12. ↑ How Ammonia Poisons Our Air , DUH, accessed January 25, 2017
  13. ↑ a b Umweltbundesamt, answers to frequently asked questions on the subject of "ozone" , no date.
  14. ^ Institute for Advanced Sustainability Studies (IASS), Short-lived Climate-Affecting Pollutants , December 2013
  15. ↑ a b German Education Server , Tropospheric Ozone , accessed on February 9, 2016