Basic idea of the building block
The chemical formation of the secondary air pollutant ozone in the troposphere from its precursors (nitrogen oxides, NOx, and hydrocarbons, VOC) is a non-linear process, depending on the meteorological conditions and the emissions. A linear description of the impacts is not possible. Therefore, some exemplary situations were calculated in advance with a complex photochemical model. The results are recallable on a dynamcal web site. This allows to demonstate the influence of various parameters (NOX emssion, VOC emission, season, wind speed, cloudiness) of the ozone formation during a lecture in a vivid way.
Detailed description of the building block
The main part of the building block is a dynamical web site that may be projected. The lecturer can show, how changing meteorological conditions and different amounts of emissions of ozone precursors effect the ozone formation in the atmosphere. The single conditions are chosen by simple clicks and the result is immediately displayed graphically.
The following parameters may be chosen:
- Two seasons with influence on temperature and solar radiation (February and July).
- Three wind speeds.
- Cloudiness (yes/no) with influence on temperature and radiation (July only).
- Three levels of anthropogenic NOx emissions.
- Three levels of anthropogenic VOC emissions.
- Biogenic emissions (yes/no), dependant on temperature and radiation. This allows to demonstrate their effect (July only).
This choice affords 135 model calculations. These have been performed during the preparation of the building block with the photochemical model CAMx for an exemplary landscape. It describes a city in the middle of a rural area. The model results were postprocessed for graphical display in this interavtive tool. For every scenario the following plots are available:
- Development of the concentration of the relevant substances (ozone, NOx, VOC) along a transsection through the model domain as animation for the daily course.
- The plot above, frozen at the time of the highest ozone concentration.
- The diurnal course of the emissions of NOx and VOC at the three land use types (urban, rural, forest).
- The diurnal course of the concentrations of O3, NOx, and VOC at three typical locations in the model domain ("measurement stations").
- The diurnal course of temparature.
By simple clicks during the presentation it is possible to switch between the scenarios and the graphs.
Additional information to describe the used model and the basics of ozone chemistry are provided as text and as viewgraph. This material as well as the interactive presentations are available online to allow the students a repitition.
Description of the application during a lecture
The whole material is available for download and can be used offline during a lecture. A web browser is the only software requirement (Firefox, Chrome, IE10). Web access is needed for an online application. The format is optimized for a projection (full screen mode). The order and the selection of the shown interactive viewgraphs can be chosen freely.
What is the special effect for the students?
It is shown in a vivid way, which effect different conditions have on the ozone formation in the atmosphere.