This section presents a variety of information on the physical environment of the United States, starting with basic area measurement data and ending with climatic data for selected weather stations around the country. The subjects covered between those points are mostly concerned with environmental trends but include such related subjects as land use, water consumption, air pollutant emissions, toxic releases, oil spills, hazardous waste sites, municipal waste and recycling, threatened and endangered wildlife, and the environmental industry.

The information in this section is selected from a wide range of Federal agencies that compile the data for various administrative or regulatory purposes, such as the Environmental Protection Agency, U.S. Geological Survey, National Oceanic and Atmospheric Administration, Natural Resources Conservation Service, and General Services Administration.

Area-For the 1990 census, area measurements were calculated by computer based on the information contained in a single, consistent geographic database, the TIGER TM file (described below), rather than relying on historical, local, and manually calculated information. This especially affects water area figures reported in 1990; these had only included those bodies of water of least 40 acres and those streams with a width of at least one-eighth of a statute mile from 1940 to 1980. Water area figures for 1990 increased because the data reflected all water recorded in the Census Bureau’s geographic database including coastal, Great Lakes, and territorial waters.

Geography-The U.S. Geological Survey conducts investigations, surveys, and research in the fields of geography, geology, topography, geographic information systems, mineralogy, hydrology, and geothermal energy resources as well as natural hazards. The U.S. Geological Survey provides United States cartographic data through the Earth Sciences Information Center, water resources data through the National Water Data Exchange (NAWDEX), and a variety of research and Open-File reports which are announced monthly in NewPublications of the U.S. Geological Survey.

In a joint project with the Census Bureau, the U.S. Geological Survey provided the basic information on geographic features for input into a national geographic and cartographic database prepared by the Census Bureau, called the TIGER TM (Topologically Integrated Geographic Encoding and Referencing) System. Maps prepared by the Census Bureau show the names and boundaries of various types of legal and statistical entities, such as places, county subdivisions, and larger areas and are available as of the specific decennial census. An inventory is available for the 1990 census, both on computer tape and CD-ROM as the 1990TIGER/GICS (Geographic Identification Code Scheme) and for the 1997 economic censuses in theGeographic Reference Manual(EC97-R-1). The Census Bureau maintains a current inventory of governmental units and their legal boundaries through its Boundary and Annexation Survey. The TIGER TM System contains information on the legal and statistical entities used by the Census Bureau, as well as on both manmade and natural features, such as streets, roads, railroads, rivers, and lakes; information is available to the public in the form of machine-readable TIGER extract files.

An inventory of the Nation’s land resources by type of use/cover was conducted by the National Resource Recovery Conservation Service (formerly the Soil Conservation Service) every 5 years beginning in 1982. The most recent survey results, which were published in the 1997 National Resources Inventory, cover all non-Federal land in Puerto Rico, the Virgin Islands, and the United States except Alaska. Tables 382 and 383 provide some preliminary results from the survey.

Environment-The principal Federal agency responsible for pollution abatement and control activities is the Environmental Protection Agency (EPA). It is responsible for establishing and monitoring national air quality standards, water quality activities, solid and hazardous waste disposal, and control of toxic substances. Many of these series now appear on the EPA Web site at the Center for Environmental Information and Statistics and can be accessed at <http://www.epa.gov/ceis/>.

National Ambient Air Quality Standards (NAAQS) for suspended particulate matter, sulfur dioxide, photochemical oxidants, carbon monoxide, and nitrogen dioxide were originally set by the EPA in April 1971. Every 5 years, each of the NAAQS is reviewed and revised if new health or welfare data indicates that a change is necessary. The standard for photochemical oxidants, now called ozone, was revised in February 1979. Also, a new NAAQS for lead was promulgated in October 1978 and for suspended particulate matter in 1987. Table 392 gives some of the health related standards for the six air pollutants having NAAQS. Data gathered from state networks are periodically submitted to EPA’s National Aerometric Information Retrieval System (AIRS) for summarization in annual reports on the nationwide status and trends in air quality; for details, see National Air Quality and Emissions Trends Report, 1998.

The Toxics Release Inventory (TRI), published by the U.S. EPA, is a valuable source of information regarding toxic chemicals that are being used, manufactured, treated, transported, or released into the environment. Two rules, Section 313 of the Emergency Planning and Community Right-To-Know Act (EPCRA) and Section 6607 of the Pollution Prevention Act (PPA), mandate that a publicly accessible toxic chemical database be developed and maintained by U.S. EPA. This database, known as the Toxics Release Inventory (TRI), contains information concerning waste management activities and the release of toxic chemicals by facilities that manufacture, process, or otherwise use said materials.

Data on the release of these chemicals are collected from manufacturing facilities and facilities added in 1998 that have the equivalent of 10 or more full-time employees and meet the established thresholds for manufacture, processing, or "otherwise use" of listed chemicals. Facilities must report their releases and other waste management quantities. Federal facilities have been required to report since 1994, regardless of industry classification. In May 1997, EPA added seven new industry sectors that reported to the TRI for the first time in July 1999 for the 1998 reporting year.

Climate-NOAA, through the National Weather Service and the National Environmental Satellite, Data, and Information Service, is responsible for data on climate. NOAA maintains about 11,600 weather stations, of which over 3,000 produce autographic precipitation records, about 600 take hourly readings of a series of weather elements, and the remainder record data once a day. These data are reported monthly in the Climatological Data and Storm Data, published monthly, and annually in the LocalClimatological Data(published by location for major cities).

The normal climatological temperatures, precipitation, and degree days listed in this publication are derived for comparative purposes and are averages for the 30-year period, 1961-90. For stations that did not have continuous records for the entire 30 years from the same instrument site, the normals have been adjusted to provide representative values for the current location. The information in all other tables is based on data from the beginning of the record at that location through 1998, except as noted.