Research Flights Seek to Improve View of Air Pollution from Space

This summer two NASA research airplanes will fly over the Baltimore-Washington region and northeast Maryland as part of a mission to enhance the capability of satellites to measure ground-level air quality from space. The flights will be supported by the U.S. Environmental Protection Agency and will aid the agency in monitoring pollutants that affect people’s health.

”With improved ability to monitor pollution from satellites, scientists can make better air quality forecasts, and more accurately determine sources of air pollutants. This information is useful in developing strategies to protect our nation’s air quality,” said Dr. Paul Anastas, assistant administrator for EPA’s Office of Research and Development.

The flight measurements will be taken in concert with satellite and ground measurements. EPA scientists will use ground-based instruments to measure oxides of nitrogen and ozone along portions of the flight path. Data from the project is expected to provide a greater understanding of how the existing ground-based air monitoring network funded by EPA and run by states and local agencies can be used to improve satellite observations.

A fundamental challenge for space borne instruments monitoring air quality is to distinguish between pollution high in the atmosphere and that near the surface where people live and breathe. The new field project will make measurements from aircraft in combination with ground-based observations to help scientists better understand how to observe ground-level pollution from space in the future.

The project is called DISCOVER-AQ, which stands for Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality. It is one of  five Earth Venture investigations selected in 2010 as part of NASA's Earth System Science Pathfinder program. These targeted science investigations complement NASA's larger research missions.

"What we're trying to do with DISCOVER-AQ is to fill the knowledge gap that limits our ability to monitor air pollution with satellites," said James Crawford, the mission's principal investigator based at NASA's Langley Research Center in Hampton, Va.

Since many countries, including the United States, have large gaps in ground-based networks of air pollution monitors, experts look toward satellites to provide a more complete geographic perspective on the distribution of pollutants.

NASA's A-Train constellation of satellites, including Aqua and Aura, will pass over the DISCOVER-AQ study area each day in the early afternoon. This data will give scientists the opportunity to compare the view from space with that from the ground and aircraft.

"Although we are better at detecting some pollutants from space than others, broadly speaking we have difficulty distinguishing between pollutants high in the atmosphere, which we can see quite well with satellites, and pollutants at the surface," said Kenneth Pickering, DISCOVER-AQ’s project scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md.

Test flights begin as early as June 27 followed by up to 14 flights during July using two NASA planes. Sampling will focus on an area extending from Beltsville, Md., to the northeastern corner of Maryland in a pattern that follows major roadway traffic corridors. The flight path passes over six ground measurement sites operated by the Maryland Department of the Environment.

Ground sites maintained by the Maryland Department of the Environment form the backbone of the surface network. These sites will supplemented by additional instrumentation provided by NASA, EPA, Howard University, Pennsylvania State University, the University of Maryland-Baltimore County, and Millersville University in Pennsylvania. In the air, NASA investigators will be joined by colleagues from the National Center for Atmospheric Research, the University of California-Berkeley, and the University of Innsbruck in Austria.

The combined scientific resources are what make DISCOVER-AQ a rare opportunity for air quality researchers. "It's not just one instrument that's more important than another. It is the combination of all of them that makes this campaign valuable," said Jennifer Hains, a research statistician with the Maryland Department of the Environment in Baltimore.