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