Implementing EKMA: Step 1

There are a variety of procedures and guidelines for ensuring that the modeling procedure includes enough model runs and calculations to reduce the likelihood of there being an error in the projected emissions controls needed to meet a particular air quality standard. The recommended procedure for EKMA/OZIP involves:

the repeated application of OZIP to generate isopleths for each of the highest five ozone days from the past three years
the use of the EKMA procedure to provide a control estimate for each day
the selection of the maximum control estimate from each control estimate

Data must be collected from air quality monitors. The recommended procedure requires the use of a minimum of three monitors:

one monitor within the city being modeled
one monitor predominatly downwind of the city
one monitor predominatly upwind of the city

It is possible, and probably likely, that there will not be three years worth of data for each of the monitors. If there is only one year worth of data, you have no choice but to accept and use that value. If, on the other hand, you have two years worth of data, the ozone concentration that you will use as a data point in the model will be the second highest value. Likewise, with three-year data, the third highest ozone concentration will be your modeling data point.

Urban Monitor Data

O3	Date	% Reduction (from OZIP)
0.24	10/1/90	60
0.18	6/8/91	57
0.16	10/2/90	45
0.15	8/13/91	39
0.14	8/21/90	*

Downwind Monitor Data

O3	Date	% Reduction (from OZIP)
0.22	6/8/91	58
0.19	8/25/90	54
0.19	10/2/90	55
0.18	8/26/90	51
0.17	7/26/89	49

Upwind Monitor Data

O3	Date	% Reduction (from OZIP)
0.16	7/31/91	45
0.15	9/17/91	*
0.15	6/1/91	*

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