By Steve Huffman
Salisbury Post
First the bad news: Rowan is one of two counties in the state out of compliance with federal ozone pollution limits. (Mecklenburg is the other.)
Now the not-so-bad news: Our air isn’t as bad as it was just a few years. And it’s getting better.
“It’s a gradual process,” said Tom Mather, a spokesman for the N.C. Division of Air Quality. “We’re seeing improvements, and I think we’re going to continue seeing more.”
The U.S. Environmental Protection Agency’s standard for allowable ozone is .08 parts per million. Parts per million is a way of measuring the concentration of ozone in the air.
Mather said Rowan is only slightly out of compliance with federal levels and said ozone readings this year haven’t been as high as they were in other recent summers.
Mather noted that there have been several years ó 1998 and 1999, especially, when, like this summer, conditions were hot and dry ó when ozone readings of .100 parts per million were not uncommon. Readings haven’t approached those levels this summer, Mather said.
He said that in 1998 there were eight Code Red days across the state while there were nine such readings in 1999.
There have been no such readings this year despite the almost-unbearable heat of late.
The state’s ozone-warning system is based on five colors. Orange is the first used to alert residents to worsening air quality, while red and purple mean things are especially bad.
Code Orange designates ozone readings between .085 and .104 parts per million. Code Red kicks in between .105 and .124 while Code Purple is anything above .125.
Mather said there have been only two or three purple readings in state history.
He said the improvement in air quality owes largely to newer cars that release fewer emissions than older vehicles.
“New cars and trucks are much cleaner,” Mather said. “As more new cars are sold, the air gets better.”
A Clean Smoke Stack Act passed by the General Assembly in 2002 has also helped curb pollutants, Mather said. He said the act aims at reducing the emissions of industries and coal-burning power plants.
Mather said Rowan’s readings are worse than most counties because the county is downwind from Mecklenburg and Charlotte’s conglomeration of traffic and industry.
He compared Rowan with Granville and Franklin counties, both of which are largely rural but ó because of their locations ó often have higher ozone readings than neighboring Triangle municipalities.
“It’s a regional problem,” Mather said.
Rowan’s ozone average from 2004-2006, the most recent recording period, was .085. Mather noted that had it been just .001 of a part per million less, the county would have been in compliance with EPA standards.
Mecklenburg’s reading for the same period was .088.
But even an ozone reading of .080 parts per million may soon not be low enough to keep counties in the EPA’s good graces. Mather said the EPA is working to lower the acceptable level to .075 parts per million or less.
Mather said the EPA will hold a hearing in the not-too-distant future concerning lowering acceptable ozone levels. Public comment will be allowed.
He said that if the EPA drops the ozone standard to .075 parts per million, 19 counties would be out of compliance.
“I think we’re going to continue to see improvements, but we may have to take additional steps” for counties to be in compliance, Mather said.
Contact Steve Huffman at 704-797-4222 or shuffman@salisburypost.com.