PHOTO-OXIDANTS IN THE ATMOSPHERE
The problem of the formation of photo-oxidants in the atmosphere can be subdivided into the following partial problems: a) The occurrence of limited (in space and time) episodes of extremely high ozone mixing ratios, which can cause acute environmental damage. b) The occurrence of ozone loads covering large areas during extended periods of good weather in summer. c) The global increase of tropospheric ozone. Partial problem a) is contributed to mainly by the emissions of highly reactive carbohydrates, of which the ozone forming effect can be evaluated + as has been described + by means of simple Smogkammer experiments. Model calculations are the means by which it is currently attempted to get round partial problem b) as uncertainty still remains as to whether the large-scale ozone burden over extended periods is best tackled via the control of the NO-x emissions or rather by the control of the carbohydrate load. Due to the complicated mutual interaction of chemistry and meteorology (expansion) this question is not likely to be answered soon. Partial problem c) is only touched upon here inasmuch as the critical NO-x mixture ratios (taken from model calculations) are quoted here; it depends on these critical NO-x mixture ratios whether the ozone balance in the free troposphere is positive, neutral or negative. There are, in fact, indications (long term measurements made on the Hohenpeissenberg) that the ozone equilibrium has already been drastically increased in the troposphere of the northern hemisphere as the result of anthropogenic influences.
Bibliographic Reference: EUR 10493 DE (1986) FS, 25 P., BFR 200, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989124134700 / Last updated on: 1987-01-01
Available languages: de