Environment and Climate Change Canada (ECCC) developed the ADAGIO (Atmospheric Deposition Analysis Generated by Interpolation of model and Observations) product, which provides maps of optimized wet, dry and total annual deposition of nitrogen, sulphur, and ozone in Canada and the United States by combining observed and modelled data. Ground-based measurements provide the most accurate data near measurement sites, but cannot provide reliable large-scale estimates of deposition where sites are sparse. Chemical transport models provide improved spatial coverage, but often have biases and uncertainties related to model parameterization. In the ADAGIO product, observational data are collected from precipitation chemistry and air monitoring networks comprising a few hundred stations across North America. Modelling data are obtained from ECCC’s GEM-MACH (Global Environmental Multiscale - Modeling Air Quality and CHemistry) model. If available, model versions that include wildfire emissions are used. The model and observational data are statistically combined using the Optimal Interpolation technique (Robichaud et al., 2025, 2026). ADAGIO provides continuous total deposition fluxes across North America, which can be used to evaluate the impacts of anthropogenic activities on ecosystem health, such as acidification and eutrophication.

ADAGIO data from developmental (research) and operational runs are provided in the subfolder collections. The developmental runs were performed for the years 2010, 2013-2016, and 2019 and are provided here in support of the papers describing the method (Robichaud et al., 2025, 2026). Moving forward, ADAGIO data from using revised emissions and updated model runs operational runs will be provided on an ongoing basis as operational outputs.

The data are available in geospatial formats (e.g. NetCDF, GeoTiff) and image formats (PNG). Please consult the README files for descriptions, updates, and recommended data citation and acknowledgement. Contact natchem@ec.gc.ca for more information.

Acknowledgements: Measurement data for ADAGIO were provided by the Canadian Air and Precipitation Monitoring Network (CAPMoN), National Air Pollution Surveillance (NAPS) Program, the Governments of Alberta and New Brunswick, the National Atmospheric Deposition Program National Trends Network and Ammonia Monitoring Network, U.S. Environmental Protection Agency Clean Air Status and Trends Network (CASTNET) and Air Quality System. Model data were provided by the Air Quality Issues Response (AQIR) group of the Canadian Centre for Meteorological and Environmental Predictions at ECCC (operational product) or the Air Quality Research Division at ECCC (developmental product). Additional details, including data links, are provided in the README files.

Robichaud, A., Cole, A., Cheng, I., Cathcart, H., Feng, J., and Hou, A. (2025). Data fusion of modelled and measured deposition in the U.S. and Canada, part I: Description of methodology and validation of wet deposition of sulfur and nitrogen. Atmos. Environ., 347, 121074, https://doi.org/10.1016/j.atmosenv.2025.121074.

Robichaud, A., Cole, A., Cheng, I., Cathcart, H., Feng, J., Hou, A., Griffin, D., and Shephard, M. W. (2026). Data fusion of modelled and measured deposition in the U.S. and Canada, part II: Dry deposition of sulfur, nitrogen and ozone. Atmos. Environ., 364, 121656, https://doi.org/10.1016/j.atmosenv.2025.121656.