The Integrated Empirical Rate Model
The Integrated Empirical Rate (IER) Model is a description of the formation of photochemical smog in the urban atmosphere. It is a key component of the AIRTRAK monitoring system which executes the model in real time from ambient monitoring data, in which case no emissions inventory data are required (Johnson & Quigley 1989). The model was derived from extensive chamber studies by colleagues at CSIRO Energy Technology (See, e.g., ECOS article about smog in Sydney and AIRTRAK. Contact email@example.com).
The IER model is used in our prognostic Lagrangian particle model, LADM, to predict concentrations of nitrogen dioxide and ozone downwind of a chimney. A more detailed smog model called the Generic Reaction Set, and of which the IER model is a solution, has also been developed (Azzi et al. 1992). An extended version of GRS is used in the air pollution model, TAPM, a new general purpose prognostic air pollution model from CSIRO. An extended GRS is also used in the Australian Air Pollution Forecasting System.
According to the Integrated Empirical Rate Model (see Johnson 1984) there are two regimes in the formation of photochemical smog in an air parcel:
Species concentrations are all measured in volume/volume units such as ppb.
[SP] = smog producedand
= 4.09At the same time and location, the following important relations hold (Johnson et al.1990):
[NOx] = [NO] + [NO2]The active nitrogen loss terms ([SNGN] and [SGN]) are taken to be proportional to [SP]:
[SNGN] = min([NOxo], P[SP])where P = Q = 0.125 = empirical loss coefficients.
Azzi M., G. Johnson, M.Cope (1992). An introduction to the Generic Reaction Set Photochemical Smog Model. In Proceedings of the 11th International Conference of the Clean Air Society of Australia and New Zealand, Eds. P. Best, N. Bofinger, and D. Cliff, 2, pp. 451-462.
Johnson G. (1984). A simple model for predicting the ozone concentration of ambient air. In Proc. 8th International Conference of the Clean Air Society of Australia and New Zealand, Eds. H. Hartmann, J. O'Heare, J. Chiodo, and R.Gillis, 2, pp. 715-731.
Johnson, G.M., S.M. Quigley and J.G. Smith (1990). Management of photochemical smog using the AIRTRAK approach. In International Clean Air Conference 1990, Auckland, New Zealand. March 25-30, The Clean Air Society of Australia and New Zealand. Editor Philippa Gibson pp. 209-214.
Wratt, D.S., M.G. Hadfield, M. Jones and G.M. Johnson (1990). Predicting the impact of a proposed gas fired power station on photochemical pollution levels around Auckland. In International Clean Air Conference 1990, Auckland, New Zealand. March 25-30, The Clean Air Society of Australia and New Zealand. Editor Philippa Gibson pp. 159-164.
Wratt, D.S., M.G. Hadfield, M.T. Jones, G.M. Johnson and I. McBurney (1992). Power stations, oxides of nitrogen emissions, and photochemical smog: a modelling approach to guide decision makers. Ecological Modelling, 64, pp. 185-203.
Modified: May 22, 2008