Emission reductions to meet deposition criteria

The paper assumes Governments are willing and able to reduce national emissions of pollution to protect the environment. Sulphur dioxide is examined as an important example. Although not necessarily true at the present time, it further assumes: 1. (i) that the cost of reducing these emissions from different industries (and other source types) are known, and that these costs include the secondary consequences of emission control (for example, possible resulting unemployment); 2. (ii) that maximum deposition criteria (mdc) have been established on some appropriate grid (above which undesirable environmental damage will occur) and that in some gridsquares these mdc are currently being exceeded; and 3. (iii) that priorities for reducing the deposition may be ascribed for each gridsquare. The highest priority may reflect concern over excessive levels of heavy metals in drinking water drawn from wells used by remote homesteads, for example. Gridsquares where more gradual, and hopefully reversible, damage is taking place would be given a rather lower priority. The paper seeks to establish maximum levels of emission in each gridsquare which will result in depositions nowhere exceeding the mdc (on the scale of a gridsquare). It also offers a means of selecting an optimum staged reduction strategy whereby emissions are reduced gradually towards the ultimate maximum levels, and at each stage of the reduction, gives the maximum benefit for the capital outlay consistent with the priorities and costs outlined above. The paper utilizes a very simple analytical model of the deposition field resulting from a single emission. The model is tuned to give the best comparison with the 1985 sulphur deposition field obtained using the much more complex EMEP MSC-W Lagrangian model used operationally for acid-rain analyses in Europe.