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Clean Air Status and Trends Network (CASTNET) Weekly Ambient Concentrations

Published by U.S. Environmental Protection Agency | U.S. Environmental Protection Agency | Metadata Last Checked: August 02, 2025 | Last Modified: 2021-02-11
Weekly average air concentrations from CASTNET filter pack data in standard Tuesday 9:00 AM - Tuesday 8:00 AM weeks. The data are collected using an open face, 3-stage filter pack. Data include aerosol concentrations of sulfate, nitrate, ammonium, calcium, sodium, potassium, magnesium and chloride and gaseous concentrations of sulfur dioxide and nitric acid. The QAPP and associated SOPs can be found on the CASTNET website: www.epa.gov/castnet/documents-reports. Site location information is included with this dataset. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.

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