The data include 1) country-based regionally classified daily PM10 concentrations in South Korea/China and 2) daily cosine similarities derived by projecting the anomalous large-scale pattern (domain: 20-80N, 30-180E) for each day during the high PM10 events (> 80 ug/m3) in South Korea to the characteristic anomalous large-scale pattern of all historical high PM10 cases in South Korea. The cosine similarities were respectively derived for geopotential heights (500 and 1000 hPa), air temperature (850 hPa), relative humidity (850 hPa), horizontal wind speed (1000 hPa), and pressure vertical velocity (1000 hPa). The number of daily data per file is 5113 for the PM10 concentration and 2873 for the cosine similarity.