Any time high pollution levels are likely, a member of the team scrambles to Kent Island for a flight. A typical mission consists of a single researcher and a pilot in one equipment-jammed plane. Yesterday, team leader Bruce Doddridge, a photographer and a reporter tailed Stehr in a larger aircraft. Until late in the afternoon, they sampled pollution levels over sites in Maryland and western Pennsylvania. What they found were lower ozone levels than the day before, especially in the Baltimore region.
Meteorologists say that brisk northwest winds helped blow the pollution away.
But east and south of Baltimore, the air was still percolating. On Tuesday, the team recorded ozone levels of about 200 parts per billion above Fallston, in Harford County, and about 210 parts per billion near Kent Island. These are the highest levels Doddridge has ever seen. Ground-level ozone levels are not supposed to exceed 120 parts per billion. Yesterday the Environmental Protection Agency moved to lower the threshold to 80 parts per billion, to protect the nation's health.