North Carolina Counties with 8-Hour Ozone Violations 2007-2009
In March 2008, the US EPA promulgated a revision of the ozone standard with a lower nonattainment threshold. We have colored the Design Value map in a novel way so that it can be compared easily to past years with the previous standard and to future years with the new standard.
Only one county, Mecklenburg, had a 3-year average of the annual 4th high value for each year equaling 0.085 ppm level or higher (violation of the 8-hour standard that was in effect from 1997 through 2007). The average for Mecklenburg County was 0.086 ppm. We present the remaining details in three tables. Table 1 refers to the ozone standard that was effective from 1997 through 2007. Table 2 and Table 3 refer to the ozone standard that was effective beginning in 2008.
Table 1. The following table shows 29 monitored counties that are attaining the 0.085 ppm standard that was in effect from 1997 through 2007. The first column lists the county; the second lists the average value for that county. On the 2007-2009 Design Value Map, these counties are colored orange and green, with orange signifying counties that would not attain the 2008 8-hour standard.
| County | Average value |
|---|---|
| Alexander | 0.073 ppm |
| Avery | 0.067 ppm |
| Buncombe | 0.069 ppm |
| Caldwell | 0.071 ppm |
| Caswell | 0.076 ppm |
| Chatham | 0.069 ppm |
| Cumberland | 0.074 ppm |
| Davie | 0.078 ppm |
| Durham | 0.074 ppm |
| Edgecombe | 0.073 ppm |
| Forsyth | 0.077 ppm |
| Franklin | 0.074 ppm |
| Graham | 0.075 ppm |
| Granville | 0.077 ppm |
| Guilford | 0.079 ppm |
| Haywood | 0.074 ppm |
| Johnston | 0.073 ppm |
| Lenoir | 0.071 ppm |
| Lincoln | 0.076 ppm |
| Martin | 0.071 ppm |
| New Hanover | 0.065 ppm |
| Person | 0.074 ppm |
| Pitt | 0.074 ppm |
| Rockingham | 0.078 ppm |
| Rowan | 0.084 ppm |
| Swain | 0.064 ppm |
| Union | 0.076 ppm |
| Wake | 0.076 ppm |
| Yancey | 0.074 ppm |
Table 2. The following table shows 11 counties with a 3-year average of the annual 4th high value for each year equaling 0.076 ppm level or higher (violation of the 8-hour standard established in 2008). The first column lists the county; the second lists the average value for that county. On the 2007-2009 Design Value Map, these counties are colored red and orange, with red signifying counties that violated the 1997 8-hour standard and orange signifying counties attaining the 1997 8-hour standard.
| County | Average Value |
|---|---|
| Caswell | 0.076 ppm |
| Davie | 0.078 ppm |
| Forsyth | 0.077 ppm |
| Granville | 0.077 ppm |
| Guilford | 0.079 ppm |
| Lincoln | 0.076 ppm |
| Mecklenburg | 0.086 ppm |
| Rockingham | 0.078 ppm |
| Rowan | 0.084 ppm |
| Union | 0.076 ppm |
| Wake | 0.076 ppm |
Table 3. The following table shows 19 monitored counties that are attaining the 0.076 ppm standard that was established in 2008. The first column lists the county; the second lists the average value for that county. On the 2007-2009 Design Value Map, these counties are colored green.
| County | Average Value |
|---|---|
| Alexander | 0.073 ppm |
| Avery | 0.067 ppm |
| Buncombe | 0.069 ppm |
| Caldwell | 0.071 ppm |
| Chatham | 0.069 ppm |
| Cumberland | 0.074 ppm |
| Durham | 0.074 ppm |
| Edgecombe | 0.073 ppm |
| Franklin | 0.074 ppm |
| Graham | 0.075 ppm |
| Haywood | 0.074 ppm |
| Johnston | 0.073 ppm |
| Lenoir | 0.071 ppm |
| Martin | 0.071 ppm |
| New Hanover | 0.065 ppm |
| Person | 0.074 ppm |
| Pitt | 0.074 ppm |
| Swain | 0.064 ppm |
| Yancey | 0.074 ppm |
Note:
- Additional counties may be involved in emission reduction strategies
- Nonattainment designations may not follow county boundaries
- Final data validation is not yet complete