This layer displays the daily average concentration of ozone and the percentage of days with concentrations of ozone above the National Ambient Air Quality Standard (NAAQS) of 0.075 parts per million in 2014.
Air Toxics – Non-Cancer Risk by Census Tract
Layer displays the modeled non-cancer risk associated with air toxics exposure. A hazard index (HI) of 1 or lower means air toxics are unlikely to cause adverse noncancer health effects over a lifetime of exposure.
Air Toxics – Cancer Risk by Census Tract
Layer displays the modeled cancer risk associated with air toxics exposure. Figures represents the likelihood of hazardous exposure per 1 million population.
National Pollutant Discharge Elimination System (NPDES)
This layer displays the locations of regulated facilities that discharge pollutants into surface waters in the United States. Location and environmental characteristics about facilities requiring discharge permits is contained in the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES). Facilities requiring permits include industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters (via discrete conveyances such as pipes or man-made ditches). Individual homes that are connected to a municipal system are not reported to the EPA. For more information, please visit the EPA National Pollutant Discharge Elimination System web page.
Brownfield Sites
This layer displays the locations of the Environmental Protection Agency (EPA) Assessment, Cleanup and Redevelopment Exchange System (ACRES) sites. ACRES stores information reported by EPA Brownfields grant recipients on brownfields properties assessed or cleaned up with grant funding as well as information on Targeted Brownfields Assessments performed by EPA Regions. A brownfield site consists of land previously used for industrial purposes or some commercial uses. The land may be contaminated by low concentrations of hazardous waste or pollution, and has the potential to be reused once it is cleaned up. For more information, please visit the EPA Brownfields and Land Revitalization website or the ACRES Information web page.
Air Facility System Sites
This layer displays the locations of regulated facilities that discharge air pollutants in the United States. The Air Facility System (AFS) contains compliance and permit data for stationary sources of air pollution (such as electric power plants, steel mills, factories, and universities) regulated by EPA, state and local air pollution agencies. The information in AFS is used by the states to prepare State Implementation Plans (SIPs) and to track the compliance status of point sources with various regulatory programs under Clean Air Act. For more information, please visit the EPA Air Facility System web page.
Air Quality System Sites
This layer displays the locations of air quality monitoring stations in the United States. The Air Quality System (AQS) contains ambient air pollution data collected by EPA, state, Local, and tribal air pollution control agencies from thousands of monitoring stations. AQS also contains meteorological data, descriptive information about each monitoring station (including its geographic location and its operator), and data quality assurance/quality control information. For more information, please visit the EPA Air Quality System web page.
Safe Drinking Water Information System Sites
This layer displays the locations of a subset of the Environmental Protection Agency (EPA) Safe Drinking Water Information System (SDWIS) sites. The SDWIS contains information about public water systems and their violations of EPA’s drinking water regulations. Data can be accessed through the EPA’s Clip N Ship map application. For more information, please visit the Safe Drinking Water Information System web page.
Ecoegions
Ecoregions are identified by analyzing the patterns and composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity (Omernik 1987, 1995). These phenomena include geology, landforms, soils, vegetation, climate, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral classification scheme has been adopted for different hierarchical levels of ecoregions, ranging from general regions to more detailed:
Level I – 12 ecoregions in the continental U.S.
Level II – 25 ecoregions in the continental U.S.
Level III -105 ecoregions in the continental U.S.
Level IV – 967 ecoregions in the conterminous U.S.
Explanations of the methods used to define these multi-agency ecoregions are given in Omernik and Griffith (2014), Omernik (1995, 2004), and CEC (1997).
Air Quality – Ozone Levels (O3) by Census Tract, 2015
This layer displays the daily average concentration of ozone and the percentage of days with concentrations of ozone above the National Ambient Air Quality Standard (NAAQS) of 0.075 parts per million in 2015.