Comprehensive Plan Glossary

NATIONAL AMBIENT AIR QUALITY: The Clean Air Act, which was last amended in 1990, requires the Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards for pollutants considered harmful to public health and the environment.

NATIONAL REGISTER OF HISTORIC PLACES: See Virginia Landmarks Register/National Register of Historic Places.

NEIGHBORHOOD SHOPPING CENTERS: Centers that range in size between 80,000 and 125,000 square feet. They serve an area within three to five minutes driving time and generally have a supermarket as the anchor store. To support a center with a supermarket anchor, a population of 10,000 or more is desirable.

NEIGHBORHOOD (MINI AND PORTABLE) LIBRARIES: Small facilities that provide popular titles and the most essential services. Monthly circulation level is 4,000 to 10,000 volumes.

NITROGEN: A nutrient, which when released into surface water, may stimulate the growth of aquatic organisms. Such organisms, upon decomposition, can adversely affect the ecological quality of a surface water body by depleting its supply of dissolved oxygen.

OPEN SPACE: The Virginia Open Space Land Act defines "open-space land" as any land which is provided or preserved for (i) park or recreation purposes, (ii) conservation of land or other natural resources, (iii) historic or scenic purposes, (iv) assisting in the shaping of the character, direction, and timing of community development, or (v) wetlands as defined in §28.2-1300. [The Virginia Open Space Land Act, Va. Code Ann. §§ 10.1-1700 through -1705 (Michie 1998)]

OPEN SPACE EASEMENT: A legal mechanism whereby a landowner retains ownership of his/her land, but grants some right(s) to the land to a public body, such as the Board of Supervisors. The Code of Virginia, Virginia Open Space Land Act, § 10.1-1700, authorizes public bodies to hold easements and also defines the purpose of open-space easements to include retaining or protecting the property value of natural or open space, assuring the availability of open space for agricultural, forestal, recreational, or open space use; protecting natural resources; maintaining or enhancing air or water quality; or preserving historical, architectural or archeological resources.

The Virginia Open Space Land Act, as paraphrased, defines "public body" as any state agency, county, municipality, park authority, public recreational facilities authority, soil and water conservation district, and community development authority having authority under the Code of Virginia to acquire land for public use. [The Virginia Open Space Land Act, Va. Code Ann. §§ 10.1-1700 through -1705 (Michie 1998)]

OZONE: An air pollutant that forms from the interactions of oxides of nitrogen and volatile organic compounds with sunlight. High ozone concentrations can adversely affect human health. Motor vehicles are the major source of oxides of nitrogen and volatile organic compounds in the Washington metropolitan area.