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EnviroAtlas - Particulate Matter Concentration (PM2.5) - Days over 35 micrograms per cubic meter in 2017 for the Conterminous United States

Published by U.S. Environmental Protection Agency, Office of Research and Development - Center for Public Health and Environmental Assessment (CPHEA), EnviroAtlas | U.S. Environmental Protection Agency | Metadata Last Checked: January 27, 2026 | Last Modified: 2021-12-16T00:00:00.000+00:00
This raster GIS dataset includes the number of days in 2017 that the concentration of particulate matter with a diameter of 2.5 micrometers or smaller (PM2.5) predicted by the Community Multiscale Air Quality modeling system (CMAQ) exceeds a threshold value of 35 micrograms per cubic meter. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).

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