Our pollution horizon
By BILL DURYEA
TAMPA -- If you were standing on Bayshore Boulevard around sunrise on Oct. 9, you would have had no difficulty determining which way the wind was blowing.
You had only to look across Hillsborough Bay at the dingy orange smoke plumes drifting steadily westward from Tampa Electric Co.'s two coal-fired power plants, Gannon near downtown and Big Bend farther south near Apollo Beach.
At that moment, as Hillsborough County stirred itself for the workday, those two plants were producing 1.6-billion watts of power.
"I think that's probably a typical morning," said Ross Bannister, a TECO spokesman.
The smoke plumes -- and plume is a pretty word for something that looks like spilled coffee on a Monet -- weren't unusual, either.
Nothing about those vast drifts of smoke prompted complaints from residents that day. Borne along on breezes more than 500 feet in the air, the plumes did not nosedive to the ground, fumigating the inhabitants of Davis Islands or Apollo Beach. Asthmatics did not shut themselves in, clutching their inhalers and waiting for a felicitous wind shift. Commuters did not dial 911 to report a fire over the port.
No, for Hillsborough County's skyline, the plumes were normal in every way.
"We were well within our limits," said Laura R. Crouch, manager of TECO's air programs. The smoke rising from the stacks can have an opacity of no more than 20 percent (100 percent would block all light); that morning the stacks averaged about 9 percent opacity.
The contrast that morning between how the plumes looked -- in short, not great -- and the amount of pollution they contained -- acceptable -- neatly encapsulates the dichotomy of how far we've come on environmental issues and how far we have to go.
There were enough leftover pollutants in the plumes that the St. Petersburg Times photographer who took the aerial photos that accompany this story followed the smoke all the way to the gulf beaches.
In other words, something that Bayshore joggers saw on the eastern horizon at dawn hung like a settling shroud over large parts of Pinellas County by the end of rush hour.
"You're seeing nitrogen oxides and particulates. Sulfur dioxide is colorless," said Jerry Campbell, director of the Air Management Division of Hillsborough's Environmental Protection Commission.
"Nitrogen oxide as it reacts in air will give you an orange color," Campbell said.
The grayish tinge, according to Peter Hessling, the air division manager for the Pinellas Department of Environmental Management, is the result of "fine particles, unburned and partially burned hydrocarbons."
"Does it look like we want it to look? No," Campbell said. "But it is within the rules. And the good news is it's going to get better."
TECO, which once ran some of the dirtiest coal-burning plants in the nation, has decreased its emissions of sulfur dioxide from 197,000 tons in 1990 to 80,000 tons in 2001. Most of that decrease came after 1998 when special "wet scrubbers" were installed at Big Bend.
The amount of sulfur dioxide that TECO's plants release is expected to drop another 471 percent by the end of 2004. That's when the Gannon plant will have completed its $700-million changeover from coal to cleaner-burning natural gas, as required in a 2000 legal settlement with the federal Environmental Protection Agency.
The air is cleaner, but last year, the Tampa Bay area suffered through five days of "unhealthy" ozone levels, according to the Hillsborough EPC. That number would no doubt be higher (Atlanta has 20 or more "bad air days" a year) were it not for the daily exchange of land and sea breezes. This year has been uncommonly ozone-free; the Tampa Bay area has yet to record an "unhealthy" day.
Scientists admit they have much to learn about the effects of pollutants -- even those that don't exceed federal guidelines -- on people and the environment.
Next week, the EPA will begin a pilot study on childhood asthma in Tampa. At the same time, state researchers with the Department of Environmental Protection and the National Oceanic and Atmospheric Administration will embark on a second round of monitoring around Tampa Bay. Their goal: determine the effect of airborne nitrates on water quality.
The effect on the bay of water runoff loaded with nitrogen-rich fertilizers has been known for some time. The nitrates encourage algae growth, algae blocks sunlight from reaching sea grasses, and fish lose prime spawning grounds. Sea grass in the bay fell from 40,000 acres in the 1950s to 25,000 acres in 1990.
"Thirty percent of the (excess) nitrogen that comes into Tampa Bay is associated with power plants, automobiles and other sources," says Holly Greening, senior scientist for the Tampa Bay Estuary Program. "That's much larger than comes in from sewage treatment plants, which is only 8 percent."
One hypothesis DEP scientists are considering is that the cumulative effect of nitrogen oxides from cars and trucks has a more immediate impact on water systems than power plants, which tend to launch their pollutants farther.
"If it's closer to the ground, it tends to have a more local effect," said Dr. Tom Atkeson, of the DEP. "It may be that pound for pound, cars have more impact."
That gap is expected to widen as TECO converts to natural gas. The first gas-powered turbine at the newly named Bayside Power Station will switch on in May. No decision has been made on whether to convert Big Bend to gas, but more powerful devices to limit nitrogen oxide gases will be added at that plant by 2005. In the meantime, the region's population -- of people and cars -- will only increase.
It won't be too long before those unsightly plumes will virtually disappear and then we'll have no easy trail to follow when we go searching for the source of the region's air pollution.
"Pretty soon we're going to run out of big point sources to point fingers at," said Noreen Poor, an assistant professor at the University of South Florida's College of Public Health, "and we're going to have to start pointing fingers at ourselves -- at our big SUVs and our lavish lifestyles."
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