See 59 FR 48396-48397. The extent to which emissions from these areas in Ohio, which are between 80 and 150 miles from the Canadian border, contribute to ozone formation in Canada is highly uncertain, particularly since winds flowing into areas in Ontario pass through a number of urbanized areas in both the U.S. and Canada. Ozone concentrations in Canada may be attributable to or fostered by ozone precursor emissions generated within Canadian borders. Yes, in Preble, and Jefferson Counties, and the counties adjacent to Columbiana County concentrations above 80 ppb have been monitored. Overall oxides of nitrogen emissions in the United States are projected to rise after the year 2000, even if mandatory CAA measures for stationary and mobile sources are implemented.
Future growth is one important factor which needs consideration.
For example, in southeast Michigan, forecasters anticipate that an additional 6 percent growth in population will, with current trends, result in a 40 percent increase in vehicle miles travelled by 2010. The area source emissions were projected to grow at the same rate as the expected population growth. The population growth rate used for Preble County is 0.83386 percent per year from 1990 to 1995 and 0.6279 percent per year from 1995 to 2005. The population growth rate used for Columbiana and Jefferson Counties was about 1 percent per year from 1990 to 2005. This factor varied by SIC but was generally around 1.1 percent per year.