Filter pack data are reported for the time interval that the filter was exposed. Continuous measurements of gases (O3, SO2, NO, NOy, and CO) and meteorological parameters are reported as hourly averages. All data are reported in local standard time (i.e. times are not adjusted for daylight savings). Daily zero, span, and precision checks are reported for ozone and trace gases.
Data are measured concentrations for each pollutant averaged over weekly, seasonal, or annual time periods. In addition, users can download ozone 8-hour daily maximum or W126 values.
Annual total (wet + dry) deposition estimates calculated by a measurement/model hybrid method (for more details on the methodology see Schwede and Lear, 2014). Annual total deposition fluxes are calculated as the sum of wet and dry deposition using measured data (from NADP/NTN, NADP/AIRMoN, and CASTNET) and modeled results (from CMAQ and PRISM). Historical dry deposition results from the MLM can be found under the Historical Deposition Data report.
Data include site details and parameters used as input to the Multi-Layer Model (MLM). The MLM is used to estimate deposition rates at by parameter for each CASTNET site.
These prepackaged datasets contain the same data as the previous four report types, but as raw csv data files for intensive data analysis.
Data include historical MLM dry and total deposition results and cloud deposition model results. Deposition velocities are calculated using meteorological measurements or historical average deposition velocities are used when meteological measurements are not available. The MLM is no longer supported by CASTNET (as of 2017). See the Annual Deposition Data report for current deposition estimates. The CLOUD deposition model provides cloud deposition results during warm weather sampling seasons. Additional information about the cloud deposition monitoring program can be found under the Documents tab.