This dataset is the estimated long-term (1981-2016) concentrations of ambient fine particulate matter across North America, which combines information from chemical transport modeling, satellite remote sensing, and ground-based monitoring. The estimates included information from updated historical emissions inventories and meteorological data, fine resolution satellite-based estimates of PM2.5, and ground-based measurements of PM2.5, PM10 and total suspended particles (TSP) measurements.

The data is annual data in HDF5 format. The variable "CorrectedPM2.5" is the concentration of fine particulate matter. The CorrectedPM2.5 variable is 100 times the value we should use. So you need to read them and divided them by 100 in your code. The NetCDF format of the dataset can be accessed via this FTP site: ftp://stetson.phys.dal.ca/jmeng/EST2019_HistoricalPM25/NETCDF/ Contact: Jun Meng (jun.meng@dal.ca)