Reducing atmospheric nitrogen


Reductions in atmospheric nitrogen deposition are diRECTly linked to water quality improvements

Almost 1/3 of the nitrogen load to the Chesapeake Bay comes from atmospheric deposition. This atmospheric nitrogen comes primarily from vehicle and power plant emissions.

The passage of the 1990 Clean Air Act Amendment’s Acid Rain Program to control vehicle and power plant emissions, as well as technological advances, have made great strides in reducing atmospheric nitrogen (N) deposition to the Bay.

A photograph of the tailpipe of a car with a cloud of exhaust behind it.
Air pollution from today’s on-road vehicles carries significant risks for human health and the environment.
A three-line graph with Discharge-weighted nitrate-nitrogen on the y-axis and Year from 1986 to 2009 on the x-axis. A dashed red vertical line represents the Clean Air Act Amendment in 1990. Three lines show surface water nitrate-nitrogen from three locations. The top line, in blue, is the Potomac River at Hancock, Maryland. The middle line, in green, is Driftwood Beach at Sinnemahoning Creek, Pennsylvania. The bottom dark-blue line is Jackson River, Virginia. All three lines trend downwards after the amendment in 1990.
Research directly linked decreases in atmospheric deposition to reductions in nitrate yields and concentrations in surface water. Data from Dr. Keith Eshleman, University of Maryland Center for Environmental Science.