Smog season begins May 1 and although last summer was a mild one for air pollution, this summer may not be so kind. According to the National Weather Services Climate Prediction Center, it's going to be a hotter, drier summer in much of the state of Georgia and the metro-Atlanta area. If those predictions are true, said Michael Chang, senior research scientist at Georgia Tech's School of Earth and Atmospheric Sciences, smog may be more of an issue this summer than it has been in recent years.

From 1987 to 2004, Atlanta has averaged 37 bad air quality days each summer. The worst year was 1999, when we experienced 69 bad air quality days. The best was last year, 2004, when we only experienced 11, said Chang.

"Changes in weather have a dramatic effect on air quality," said Chang. "Generally, hotter and drier summers lead to more bad air quality days, while cooler, wetter summers lead to fewer bad air quality days. A quick turnaround in air quality usually indicates the change is weather driven."

Chang is part of the Atlanta Air Quality Forecasting Team, a group of scientists from the Georgia Environmental Protection Division and Georgia Tech that forecast air quality during the summer months. He has spent the past three-and-a-half years engaged in a $2.8 million study on assessing urban and regional air pollution in Georgia.

A Regional Approach to Air Quality

The Fall Line Air Quality Study focused on Macon, Augusta and Columbus, with Atlanta contributing to poor air quality in each of these cities. The study not only measured air pollution levels in these areas, but also pinpointed the source of pollutants and evaluated steps these communities and their neighbors can take to reduce pollution.

The study found that while Columbus and Augusta are likely to continue to meet federal air quality standards through 2012, Macon will likely need to implement more pollution controls if it wants to meet those standards by the federally mandated 2009 deadline and maintain it through 2012.

"The sources of air pollution in Macon are varied and include mobile sources, like cars and trucks as well as industrial sources, like factories and other manufacturing facilities," said Chang.

But regional sources, such as those in surrounding counties and neighboring metropolitan areas also affect air quality in Macon. Power plants located outside of the immediate Macon area, and the many sources in the Atlanta area were found to have a significant effect on Macon's air.

As such, regional efforts may also be cheaper than trying to reduce the sources of pollution in each city. The study found that if the controls that cost the least amount of money were implemented in Augusta and its environs, reducing the level of ozone in Augusta by 1 part-per-billion (ppb) would cost about $3 million. But, if only pollution sources in Augusta were reduced, the cost to trim ozone by the same amount would increase by 50 percent. In Columbus, the effect is even more pronounced. If Columbus takes a regional approach, its cost estimate is roughly the same as Augusta's. But if the city has to do it alone, that cost would balloon by 300 percent.

"If we can use the most cost effective controls, no matter where they are, we can do it much more cheaply than if we are restricted to controlling pollution within the city and county limits," said Chang. "If we are confined to the city limits, then the controls we put in place may not be the most cost effective. This drives up the price of clean air."

Many of the pollution controls have no cost at all, the study found. Discouraging school buses from idling and implementing a burning ban during certain months would cost virtually nothing. But the zero-cost solution that would have the biggest benefit on Macon's air is continuing to use Powder River Basin (PRB) coal for use at the Georgia Power plant in Scherer. PRB coal must be imported from Wyoming, but is cleaner than its East-Coast cousin. If all the zero-cost measures in the Macon area were used, said Chang, the area would see a 1.72 ppb reduction in ozone levels.

Other controls may open up new business opportunities. Adding electrical outlets to truck stops in Macon, Augusta and Columbus could reduce heavy-duty vehicle emissions in each locality by 2.6 percent. But truck stop owners could likely make up the cost by charging for electricity. And with the cost of gasoline continuing to climb, trucking companies may actually save money paying for electricity because it would mean that truckers no longer have to idle their engines to produce juice for their cab saving on high fuel costs.

"When we began this study, each of the three communities wanted to take immediate action to improve air quality, but they didn't know what they should do," said Chang. "Should they go after local sources or more distant ones - cars and trucks or factories and power plants? We have provided them with a menu of options that describe not only the actions they can take, but also the potential costs and benefits of those actions. While tough decisions still need to be made. Armed with the information from our study, Augusta, Macon, and Columbus, working with the state and federal regulatory agencies, can now develop a plan for improving or maintaining air quality that is effective, efficient, and equitable."