STEVE INSKEEP, host:
Even as it finished the shuttle program this summer, NASA has focused on some flights at lower altitudes. This summer the agency has flown research planes between Washington, D.C. and Baltimore, Maryland. NPR's Jon Hamilton reports this space agency is investigating air pollution here on Earth.
JON HAMILTON: One reason NASA picked this busy traffic corridor to fly over is that it's a particularly bad place to inhale. Ken Pickering is a scientist from NASA's Goddard Space Flight Center, which happens to sit right next to the D.C. Beltway.
Mr. KEN PICKERING (NASA Scientist): The Baltimore/Washington area is a rather polluted region. Maryland violates the national ambient air quality standards for both ozone and for particulate matter.
HAMILTON: Ozone can damage your lungs. Airborne particles have been linked to cancer and heart attacks. And even though air pollution isn't as bad as it was, more than 125 million Americans still live in places that often fail to meet EPA air quality standards.
So NASA is trying to figure out how pollution behaves in the atmosphere. Does ozone form over the freeway or downwind in another state? How much pollution stays at ground level and how much rises high into the air? To find out, you need to take instruments up where the action is.
For weeks, Pickering and others have been flying out of a NASA facility in Wallops Island, Virginia, about 100 miles south of Washington, D.C. On this morning, he's in a makeshift office next to a cavernous hangar, getting ready for a flight.
Mr. PICKERING: Who all we got on the line?
Mr. RICH FERRARE: Rich Ferrare.
Mr. PICKERING: Hi, Rich.
MELANIE: I'm here, it's Melanie.
Mr. PICKERING: Hi, Melanie.
Mr. CHRIS LOUGHNER: Chris Loughner's on the line.
Mr. PICKERING: Chris...
HAMILTON: Pickering has bad news about one of the instruments on the P-3, the plane that serves as their flying laboratory.
Mr. PICKERING: OK, well, we're still in a hold here at Wallops concerning the P-3. The pump for the ozone instrument failed this morning.
HAMILTON: After the call, Pickering says ozone measurement is always important, but especially today.
Mr. PICKERING: Today is going to be a very hot day in the Baltimore-Washington area. Only some scattered clouds. And this will allow plenty of sunlight to cook up a lot of ozone.
HAMILTON: After a two-hour delay, the mission's principal investigator, Jim Crawford, arrives with news that the pump has been replaced.
Mr. JIM CRAWFORD (Mission Investigator): We have an ozone instrument. So if you want to proceed out to the plane, I'm hoping we're out of here, maybe half hour, 45 minutes at the worst.
HAMILTON: The P-3 is a four-engine turboprop that was designed in the 1950s to hunt enemy submarines. Crawford says now it's sniffing out dangerous chemicals and particles.
Mr. CRAWFORD: I'll just show you here as we're walking up to the plane. You know, it looks like any other aircraft, but then you begin to notice tubes and probes poking out the sides.
HAMILTON: Which allow the instruments inside to sample the air. Crawford climbs a set of rolling stairs and steps through a door into what used to be the cabin.
Mr. CRAWFORD: You're looking at a plane with a fuselage that's basically been emptied to start. And so we build these instrument racks which are basically I would say maybe 4.5 feet tall and three feet wide that we anchor to the floor and then begin to fill with scientific instruments.
HAMILTON: Any room left over is for the scientists.
(Soundbite of aircraft)
HAMILTON: After takeoff we fly north, and the fields below give way to urban sprawl and the concrete stripes of major highways.
Mr. BRIAN YATES: Alright, guys, we're over Point Charlie once again. We're at 9,700 feet MSL and descending.
HAMILTON: The plane is a hive of activity.
Mr. BRUCE ANDERSON (NASA Langley Research Center): I'm Bruce Anderson from NASA Langley Research Center. We're measuring aerosol size, number, density, composition and light scattering properties.
Ms. STEPHANIE VAY (Scientist): Stephanie Vay and we're measuring carbon dioxide here.
Mr. DAVID VAN GILST (Scientist): David Van Gilst, I'm operating the REVEAL Housekeeping data system.
Mr. TOMAS MIKOVINY (Scientist): Tomas Mikoviny, I'm from the University of Innsbruck...
HAMILTON: NASA's Bruce Anderson says it's a bad day for air quality, which makes it good day to collect data.
Mr. ANDERSON: They say that there's a red condition in a lot of the surface stations, which means that ozone levels are exceeding the EPA recommended exposure levels.
HAMILTON: The plane follows Interstate 95 at an altitude of about 1,200 feet, low enough to make out the color of each car and truck. Then, at a designated point, it begins a steep spiraling ascent to more than 10,000 feet. That allows the scientists to see how pollution levels are changing with elevation. Anderson says usually the air gets much cleaner at higher altitudes.
Mr. ANDERSON: Today the pollution is extending up to about 8,500 feet. So you have to get above that level before you really see a clear blue sky.
HAMILTON: The P-3 is just part of this NASA mission, known as DISCOVER-AQ.
There are other planes in the sky, boats on Chesapeake Bay, and sensors on the ground. And in a field near Beltsville, Maryland, scientists gather to launch a weather balloon just before the P-3 flies overhead.
Unidentified Man #1: Wow, it's going vertically upwards.
HAMILTON: The plane appears right on time.
Unidentified Man #2: There it is.
HAMILTON: The P3 flies a circuit that takes it perilously close to Baltimore Washington International Airport. It takes four people in the cockpit to make sure the NASA plane stays clear of other flights.
Unidentified Man #3: I got him. I got him, I got him. Got him on the left. Yeah, there he is. See him. Kevin, in the window. You got him, Rich?
Unidentified Man #4: Yeah, I got him. He's going above.
Unidentified Man #3: Okay.
HAMILTON: The DISCOVER-AQ mission isn't just about understanding pollution in this one area. NASA will be flying over other cities in the coming years. The ultimate goal is to figure out how to use satellites to monitor pollution across the country. NASA's Jim Crawford says right now satellites can't do that very well.
Mr. CRAWFORD: They paint great visual pictures of pollution but they don't allow us to make clear judgments on exactly how much pollution exists and at what altitude in the atmosphere it resides. And ultimately our colleagues at EPA that we work with in terms of making regulatory decisions really need to know what's happening down at nose level, where people are being influenced by pollution.
HAMILTON: The Environmental Protection Agency can't enforce air quality standards without precise measurements that show what's happening. And Crawford says good pollution measurements from a satellite would be a major improvement on today's patchwork of ground measurements, which have lots of gaps.
Mr. CRAWFORD: So what a satellite can begin to do is to fill those gaps, what's happening in these urban areas, and many times what's happening downwind of these urban areas, where the chemistry has a time to develop and potentially cause worse air quality away from the emissions, not where they're occurring.
HAMILTON: Today's flight will be a long, hot, hectic and noisy six hours in the air. But the scientists on board say it's worth it because of what's at stake. David Knapp is from the National Center for Atmospheric Research.
Mr. DAVID KNAPP (National Center for Atmospheric Research): I look at the atmosphere as like an astronaut might look at a spacesuit, saving his life all the time and caring about what happens to it.
HAMILTON: Knapp says the atmosphere is what keeps us alive as our planet hurtles through space. He says this NASA mission should serve as a reminder of that.
Unidentified Man #5: Alright. We're done.
HAMILTON: Jon Hamilton, NPR News.