Regional Differences in Ozone
Region 4: Kentucky, North Carolina, South Carolina, Georgia, Tennessee, Alabama, Mississippi, and Florida
Local Sources of VOCs
Region 4 produces more VOC emissions (4.15 million tons in 1999) than any other section of the country The largest sources generated by human activity are transportation, which accounts for 46 percent, almost the same as the nation as a whole, which is 47 percent. Of these sectors, the percentage from highway vehicles is greater in the Southeast than it is in the nation (32% v 29% nationwide). Off-highway vehicle sources are lower in the Southeast than nationally (14% v 18%). Solvent use contributed 24 percent of VOCs in the Southeast, compared with 27 percent nationally.
Local Sources of NOx
Region 4 produces more NOx emissions (5.4 million tons in 1999) than any other section of the country. The transportation sectors make up a larger portion of the NOx sources in the Southeast (59%) than they do in the nation as a whole (55%). This is largely due to highway vehicles, which produce a much larger portion of the total in the Southeast (44% v 33%). The next largest sources are emissions from electric utilities, at 24 percent, which is about same as nationally. Industrial fuel combustion makes up a lower percentage in the Southeast than nationwide (9% v 12%).
Trends
Monitored data show ozone levels in the Southeast have declined, but not as swiftly as the nation as a whole. The ozone levels dropped in the region by 2 percent from 1982 to 2001, much less than the nation which dropped by 11 percent. Furthermore, the long-term decline could have been greater had not the region’s ozone levels risen by 9 percent in the 1990s.
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