Air pollution doesn’t just cloud the air we breathe. It also harms our land and water.
What goes up must come down: just like anything else, pollution released into the air will eventually fall back to the earth’s surface. This process is called atmospheric deposition.
There are four main sources of air pollution in the Chesapeake Bay region: stationary and area sources, mobile sources, agricultural sources, and natural sources.
Stationary and area sources do not move. They have a fixed location.
Mobile sources move. Collectively, mobile sources produce a significant amount of air pollution.
Mobile sources include cars ans trucks, boats, airplanes, gas-powered lawn tools, farm and construction equipment, and other off-road vehicles.
Agricultural sources include farm operations that generate emissions of gases, particulates and chemicals.
Ammonia is the main type of air pollution emitted from agricultural sources. Ammonia comes from animal manure that is stored in holding areas and applied to the land as fertilizer.
Natural sources of air pollution are not caused by human activities. Natural sources include lightning, dust storms, forest fires, erupting volcanoes, and wild animals in their natural habitat.
Nitrogen and chemical contaminants are two kinds of air pollution that can eventually reach the Bay and its rivers.
Airborne nitrogen is one of the largest sources of pollution to the Chesapeake Bay and its rivers. Scientists estimate that about one-third of the nitrogen that pollutes the Bay comes from the air.
Nitrogen oxides and ammonia are the two major types of airborne nitrogen that pollute the Bay.
About 50 percent of the airborne nitrogen that reaches the Bay comes from sources within the Bay watershed. The other half originates as far away as Ohio, Canada and South Carolina. The area of land where nitrogen released into the air can eventually wind up in the Bay is known as the Chesapeake Bay airshed. The Bay’s NOx airshed is very large: approximately 570,000 square miles, or nine times as large as its watershed.
When too much nitrogen gets in the water, large algae blooms can form. Algae blooms block sunlight from reaching bay grasses and lead to low-oxygen areas where no life can exist.
Mercury, PCBs and PAHs are three chemical contaminants that are released into the air and can pollute the Bay.
Once in the water, these contaminants bind to sediment and move through the food web when larger animals eat small, bottom-dwelling organisms. Humans can be exposed to these toxic chemicals when they eat contaminated fish. Fish consumption advisories are widespread throughout the Chesapeake Bay region due to mercury and PCB pollution.
To restore the Chesapeake Bay, we must also clean up our air. Overall, emissions of harmful pollutants such as nitrogen and mercury are decreasing. However, more reductions are needed to meet new pollution limits for the Bay and its rivers.
New federal and state regulations, as well as better technology, are significantly reducing harmful emissions from vehicles and power plants. However, ammonia emissions have remained steady. As stronger laws take effect and on-the-ground restoration efforts continue, overall air pollution is expected to decline even further.
The EPA has proposed draft nitrogen and phosphorus limits, called allocations, as part of a "pollution diet".
Publication date: November 11, 2001 | Type of document: Report
This is a report on Deposition of Air Pollutants to the Great Waters: First Report to Congress.
Publication date: November 01, 2001 | Type of document: Report
The Significance of Ammonia to Coastal and Estuarine Areas is a report on the third Shared Resources workshop on Airsheds & Watersheds. The report covers the potential detrimental effects of ammonia to air quality' the role ammonia plays as…
Publication date: August 01, 2001 | Type of document: Report
The report describes results from five sampling periods and examine the effects of atmospheric nitrogen deposition on changes in algal biomass, as well as major algal classes.
Publication date: September 30, 2000 | Type of document: Report | Download: Electronic Version
The overall modeling framework used to assess Virginia's tributary strategies in 1999 is documented. This synthesis report provides an overview of the Chesapeake Bay Program airshed, watershed, and estuary models and other diagnostic tools…
Publication date: June 28, 2000 | Type of document: Policy Memorandum
This is a brief description of air quality in the Chesapeake Bay region
Publication date: January 01, 2000 | Type of document: Report | Download: Electronic Version
This document contains the method of producing both the Chesapeake Bay Program Land Use and the Phase 4.2 Watershed Model Landuse. It also documents the hindcasting & forecasting of model land use, the development of model segmentation, and…
Publication date: November 16, 1999 | Type of document: Report | Download: Electronic Version
A continuous deterministic environmental model of the Chesapeake Bay Watershed (HSPF), linked to an atmospheric deposition model (RADM) is used to examine nutrient loads to the Chesapeake Bay under different management scenarios. Model…
Publication date: June 01, 1999 | Type of document: Brochure
This work contains the following themes as they relate to the Chesapeake Bay: Watersheds, Environmental Stewardship and Sustainability of the Bay/Stewardship
Publication date: June 01, 1997 | Type of document: Report
This report is a review and assessment of the existing literature on the following topics: distribution of sources and atmospheric concentrations and deposition of ammonia and watershed cycling of NHx.
Publication date: March 07, 1997 | Type of document: Report
This report summarizes the findings of the workshop. The first objective of the workshop was to determine connections between issues, programs, agencies, organizations, and jurisdictions to advance their abilities to address atmospheric…
Publication date: January 01, 1997 | Type of document: Report
This work contains the following themes as they relate to the Chesapeake Bay: Watersheds
Publication date: January 01, 1997 | Type of document: Report
Second report to Congress on the atmospheric deposition of pollutants to the Great Waters. This report documents findings since the First Report to Congress and describes recent progress in these issues. This report places emphasis on local…
Publication date: November 01, 1996 | Type of document: Report
Eutrophication -- low dissolved oxygen -- caused by excess nutrients, is the most significant water quality problem facing the Bay. The Chesapeake Bay Program jurisdictions have committed to reduce nitrogen and phosphorus pollution reaching…
Publication date: October 11, 1995 | Type of document: Report
This report summarizes the workshop proceedings which focused on atmospheric nitrogen compounds. Scientists in key policy and regulatory officials explored mechanisms by which air and water pollution control programs worked together to…