Paving the Way for Space-Based Air Pollution Sensors

Although the nation’s air has grown significantly cleaner in recent decades, about 40 percent of Americans – 127 million people – live in counties where pollution levels still regularly exceed national air quality standards established by the Environmental Protection Agency.

Most of the areas with the heaviest pollution are in California, but other parts of the country are anything but immune. On the drive down I-95 between Baltimore and Washington D.C., for example, sweltering summer heat and relentless traffic often leave plumes of polluted air stewing over the highway making the area one of the top 20 smoggiest metro areas in the country.

Come July, all that health-sapping pollution will have company: a 117-foot P-3B NASA research aircraft flying spirals over six ground stations in Maryland. The aircraft is part of a month-long field campaign designed to improve satellite measurements of air pollution.

The name of the experiment -- Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER -- AQ) -- is a mouthful, but its purpose is simple.

“We’re trying fill the knowledge gap that severely limits our ability to monitor air pollution with satellites,” said James Crawford, the campaign’s principal investigator and a scientist based at NASA’s Langley Research Center in Hampton, Va.

The fundamental challenge for satellites measuring air quality is to distinguish between pollution near the surface and pollution higher in the atmosphere. Measurements from aircraft, in combination with ground-based measurements, offer a key perspective that makes such distinctions easier to make.

Twelve to fourteen flights are planned throughout July using two primary planes. The P-3B, a four-engine turboprop that returned recently from a deployment to the Arctic, will carry a suite of nine instruments, while a smaller two-engine UC-12 will carry two instruments.