Air Deposition
Approximately one-third of the nitrogen that reaches the Bay comes from emissions into the air from a range of sources, such as car exhaust.
Approximately one-third of the nitrogen that reaches the Bay comes from emissions into the air from vehicles, industries, power plants, dry cleaners, gas-powered lawn tools and other emissions sources. Federal and state laws, as well as regional restoration initiatives, will help reduce the amount of nitrogen and chemical contaminants that pollute the Bay and its tributaries.
Chesapeake Bay Program Goal to Reduce Airborne Nitrogen
Since 1985, the Chesapeake Bay Program has been working towards a goal to implement enhanced air pollution controls that will correct nutrient-related problems in the Bay and its tidal tributaries by 2010. Though just 9 percent of the air nitrogen reduction goal has been achieved, progress is expected to accelerate dramatically over the next few years as new federal air pollution control efforts take effect.
Federal Rules to Reduce Air Pollution
The Bay Program partnership is relying on federal and state laws that regulate emissions to significantly reduce airborne nitrogen.
Implementation of Clean Air Act and related regulations would achieve nitrogen reductions of about 15 million pounds annually by 2010.
- The EPA Clean Air Interstate Rule will reduce nitrogen oxide (NOx) emissions from power plants in 29 eastern U.S. states and the District of Columbia in two phases.
- Effective implementation of other federal and state Clean Air Act programs will result in further reductions in the Bay watershed.
Reducing the release of airborne nitrogen is likely to reduce the release of toxic chemical contaminants as well. The Clean Air Mercury Rule and state power plant emissions laws in Maryland, Virginia and Pennsylvania specify reductions that will decrease the amount of mercury that reaches the Bay via emissions.
On-The-Ground Efforts to Reduce Air Pollution
The way we use the land has a significant affect on the amount of airborne nitrogen that reaches the Chesapeake Bay and its rivers. For example, nitrogen that falls on forests can be absorbed and filtered by trees and plants before the pollutant reaches local waterways. Conversely, nitrogen that lands on roads, sidewalks and other impervious surfaces can be carried by stormwater runoff into the nearest storm drain.
To help reduce the effects of airborne nitrogen, tributary strategies — clean-up plans for each tributary in the watershed — are implementing actions such as:
- Maryland Healthy Air Act: Information from the Maryland Department of the Environment on expected emissions reductions from the Maryland Healthy Air Act, the toughest power plant emission law on the East Coast.
- Clean Air Act: Details of the federal Clean Air Act from the U.S. Environmental Protection Agency.
- Clean Air Mercury Rule: Details of the federal Clean Air Mercury Rule from the U.S. EPA.
- Progress on Chesapeake Bay Enforcement: An interactive map from the U.S. EPA that shows federal enforcement actions against violations of laws resulting in nutrient, sediment and air pollution in the Bay watershed and airshed.