FORT MEADE – The twin-engine plane buzzed Tipton Airport’s runway around 11 p.m., then spiraled up in a corkscrew pattern at about 500 feet per minute.
Folded in the backseat, meteorologist Lackson Marufu monitored a laptop computer and a stack of sophisticated instruments that register minute-by-minute measures of air pollutants as the plane climbed.
By the time the plane was several thousand feet up, the cars on Interstate 95 twinkled in the darkness.
Somewhere between the cars below and the stratosphere above is the answer Marufu and fellow researchers are looking for: How much of the region’s pollution is generated locally and how much blows in from distant sources like coal-fired power plants hundreds of miles away in the Ohio Valley.
“They are producing the precursors of the gases we are measuring,” Marufu said of the chemicals from car engines and power plants that combine with sunlight to form haze on high ozone days.
“Studying these chemicals helps meteorologists predict high ozone days and determine how much of the area’s pollution is generated locally and what percent blows in from power plants in the Ohio Valley,” said Marufu, wearing a red light on a headband so he could see in the dark cockpit.
Marufu and other members of his team have logged hundreds of hours, maybe thousands, in this Piper 23-250 Aztec-F, a mule of a plane that is not so fast but can carry the load of devices that measure everything from temperature and air pressure to greenhouse gases and ozone precursors.
Last summer, they conducted 54 research flights from Virginia, through Maryland and up the coast into Pennsylvania, Massachusetts, New Hampshire, New York and Maine. They do these flights both upwind and downwind of cities, allowing them to measure how much pollution the metropolitan areas are generating and how much is blowing in.
Marufu’s predecessor, Bruce Doddridge, had been performing these aerial tests since the mid-1980s. Even with all the data they have collected and analyzed, they say they need more before forming any concrete conclusions.
“Here’s your typical scientist saying we need more money,” Doddridge laughs. “I don’t want to put our reputation, the University of Maryland reputation, on the line until we have maybe another five years of data.”
But the researchers will say with certainty that East Coast cities such as Washington and Baltimore are only partly to blame for their pollution problems.
They know this because of the “signatures” of the air pollution they sample. By measuring the size and composition of particles in the air, they can determine their source.
A high concentration of carbon monoxide, for example, suggests that the pollutants come from cars. A high concentration of sulfur found upwind of the cities implies that the air is blowing in from somewhere out west, most likely from the old and heavily polluting power plants that burn sulfur-tainted coal in the Ohio Valley.
Some policy makers in that region, including Sen. George V. Voinovich, R- Ohio, and Rep. Ted Strickland, D-Ohio, reject this idea, but Marufu and his colleagues are confident in their findings.
“Like so many problems in this global era, these problems are not local or even state, they are national and global,” Marufu said.
But Doddridge says that while a portion of the problem is “transport pollution” from the far-away plants, they are not totally to blame.
“I’m no industry lap dog. I owe them nothing,” he said. “But it is not all the (fault of) industries. That’s something we’ve found so far.
“These urban-industrial-transport corridors need to accept some of the blame. That’s not to say that the power companies are blameless,” Doddridge said.
About 9,500 feet above Interstate 95 and Tipton Airport, the plane stops its climb. It is cold up here, but Marufu tells the pilot to keep the heat off because the air it blows does not smell fresh.
“Ozone can transport above that. In fact, the largest amount of ozone is in the stratosphere,” Marufu said.
But to go any higher requires a pressurized cabin or oxygen masks. So the plane turns a few more lazy circles, then, taking still more measurements, it begins to spiral back down toward the ground.