A perplexing spike in air pollution levels last week pushed Augusta over the legal threshold that triggers non-attainment status under the U.S. Clean Air Act.
"It rings the bell," said Dr. Michael Chang, a professor at Georgia Tech's Center for Urban and Regional Ecology who is studying air pollution trends in Augusta, Macon and Columbus.
The primary concern is ozone - a mix of nitrogen oxides and volatile organic compounds spawned by car exhaust and industrial emissions. Excess levels cause a host of respiratory and health problems.
Ozone once was measured on a standard in which hourly levels could not exceed .120 parts per million. The new federal standard uses eight-hour averages that cannot exceed .085 parts per million.
In 2000, Augusta had six days when excessive ozone levels were recorded. But after a relatively mild 2001 in which only three violations occurred, scientists wondered whether there would be enough pollution to study.
Excessive ozone levels Thursday and Friday, however, brought to four the number of violations recorded in Augusta so far this year.
"In general, if you average four excessive days or worse over a three-year period, then you can kind of expect your area meets the criteria for non-attainment," Dr. Chang said.
The specific federal definition of non-attainment is a little more complicated, however, but Augusta still meets it, he said.
The specific formula involves taking the fourth-worst day of the year for three consecutive years and averaging them. If the resulting ozone-level average is .085 or greater, the legal definition of non-attainment is met.
According to Georgia Environmental Protection Division records, the fourth-highest level in 2000 was .091, followed by .082 in 2001 and .085 so far this year. That averages to .086.
Cities declared non-attainment zones will join Atlanta and other metro areas that face vehicle-emissions requirements, restrictions on industry and reduced eligibility for transportation dollars.
During Augusta's violations Thursday and Friday, eight-hour averages of .085 and .089 were recorded. Because it was a holiday period, scientists could have more of a challenge figuring out why it happened.
"It's a little harder to analyze," Dr. Chang said. "We monitor industrial production and transportation patterns, so it would be much better if it had occurred on a business-as-usual day."
Dr. Chang and his colleagues are involved in the ongoing Fall Line Air Quality Study, which includes monitoring stations in Augusta. He said the teams will continue to try to identify any unusual behavior - besides weather - that could have contributed to excess pollution on those days.
TOO MUCH OZONE
2002 ozone violations in Augusta to date:
(The federal standard is .085.)
Reach Robert Pavey at (706) 868-1222, Ext. 119 or firstname.lastname@example.org.