Ozone is only one of several environmental issues associated with the VOC and NOx emission precursors. All ozone nonattainment areas should be considered ozone problem areas. Since ozone nonattainment is directly correlated with population density regional planning should be incorporated into any control strategy adopted. All areas of the OTAG region contribute to ozone transport to some degree. A process of continuous improvement should be adopted that will allow for measurement verification, while allowing for meteorological variability, of control strategy effectiveness.
Historical trends indicate that control strategies already implemented are working.
All emissions should be capped, while allowing for uncontrollable meteorological influences, based on historical data to maintain the trend. This is especially true in the nonattainment areas. In some regions of the OTAG domain, peak ozone concentrations and the number of exceedances have declined dramatically over the last 15 years. Only a few urban areas exceed the current standard several times per year on average. Transport of meteorological conditions is not the same as transport of ozone.