Two NASA research aircraft will fly over the Baltimore-Washington area of northeastern Maryland through July as part of a mission to enhance the measurement of ground-level air quality from space.

One of the aircraft, a 117-foot P-3B, will fly spiral profiles over six ground stations in Maryland throughout the month. These profiles will extend from 15,000 feet to as low as 1,000 feet from the ground. Between ground stations, flights will sample air along traffic corridors at low altitude.

Twelve to 14 flights are planned throughout the month. The P-3B, a four-engine turboprop, will carry a suite of nine instruments, while the two-engine UC-12 will carry two instruments.

Sampling will focus on an area extending from Beltsville, Md., in the southwest to the northeastern corner of Maryland in a pattern that follows major traffic corridors.