In this paper, we introduce a quantitative classification of dust events on the basis of dust, PM10 concentration, and wind speed for northeast Asia. The empirical relationship between visibility and PM10 concentration is established by regression of visibility and PM10 concentration that were taken every 5 min at 11 sites in the spring of 2004 and 2005. The empirical relationship is then applied to establish the spatial and temporal patterns of dust and PM10 concentrations by using the visibility data obtained from 1680 meteorological stations in the spring seasons of 2000--2005. The results showed that the PM10 concentration estimated from visibility is consistent with the observed PM10 concentration. The classification standard of dust events used by different countries did not show consistent results in northeast Asia. It is recommended that dust events in northeast Asia be classified as follows: (1) severe dust storm, ρ TSP ≥ 6000 5g m-3, ρ PM10 ≥ 5000 5g m-3, and v ≥ 10 m s-1; (2) dust storm, 3000 5g m-3 ≤ ρ TSP < 6000 5g m-3, 3000 5g m-3 ≤ ρ PM10 < 5000 5g m-3, and 10 m s-1 ≤ v < 15 m s-1; (3) blowing dust, 900 5g m-3 ≤ ρ TSP < 1500 5g m-3, 200 5g m-3 ≤ ρ PM10 < 600 5g m-3, and 5 m s-1 ≤ v < 10 m s-1; and (4) floating dust, 750 5g m-3 ≤ ρ TSP < 1200 5g m-3, 200 5g m-3 ≤ ρ PM10 < 400 5g m-3, and 2 m s-1 ≤ v < 5 m s-1.