Particle number (CN3) hourly medians measured at Kennaook Cape Grim 1977 to 2007 using the Automated Pollack Counter

This data set is the record of hourly median number concentration for particles greater than 3 nm in diameter (CN3) measured at the Kennaook Cape Grim Baseline Air Pollution Monitoring Station (KCGBAPS) between 1977 and 2007.\nThe KCGBAPS is located on the northwest tip of Tasmania (40.6833° S, 144.6833° E). Commencing operations in 1976, and in its current facilities since 1981, the Baseline Air Pollution Station at Kennaook Cape Grim is Australia’s contribution to international efforts for monitoring the global background atmosphere for trends due to human activities and natural variability.\nSubsets of these data have been described in Bigg et al. (1984), Gras (1990a), Gras (1990b), Gras and Whittlestone (1992), Gras (1995), Gras and Keywood (2017).\nSee KCGBAPS_CN3_Pollack_1977_2007_README.pdf for references and details of measurement method\n\nLineage: The measurement of CN3 commenced in 1977. The data published here were determined using an automated replica 1957 Pollak photoelectric nucleus counter (Metnieks and Pollak, 1959). Hourly medians were calculated from 15 direct readings per hour made by the counter. This counter was referenced daily to a manually-operated Reference CSIRO Pollack Counter. In turn this Reference CSIRO Pollack Counter was referenced to the Standard CSIRO Pollack Counter used solely for calibration purposes once or twice per year. Cross-referencing of the Standard CSIRO Pollock Counter with NOAA GMCC counters, details on the absolute calibration and stability of the CSIRO standard and the cross-referencing of the Cape Grim and standard counters are given in Gras (1984, 1988). \nThe data published here are the hourly medians under all wind direction and windspeeds (i.e. all conditions). Missing data are represented as NAN. Missing data occurred for several reasons including instrument failures (e.g., failure of the microprocessor, replacement of o-ring, flooding of the instrument) or regular calibration and maintenance activities.\nSee KCGBAPS_CN3_Pollack_1977_2007_README.pdf for references