Air, land and water quality data on a state by state and even county by county basis for the United States. GIS data archive with digital data from New York, New Jersey, Puerto Rico and the Virgin Islands. Data are available in ArcView shapefile format and ArcInfo export format. Includes water quality standards, statistics on sediment impurities, runoff, effect of dams on watersheds, toxic waste listings, Superfund sites, point pollution sources, and much more. This site provides a limited number of key research data sets from research on the Hudson River available for download.
Some files are fairly large.
All data sets in the Depot have corresponding meta data descriptions. Access to the world's largest archive of computerized social science data and Resources for social scientists using advanced computer technologies. This is an FTP site, so you will need to know what you want before downloading. File naming is done by longitude and latitude. Landuse files are also available for the entire country if you browse up a level or so.