Impact of North Atlantic-East Asian teleconnections on extremely high January PM10 cases in Korea

Highlights: • Extremely high PM₁₀ (EH) cases are associated with atmospheric stagnant pattern. • In EH cases, the PM₁₀ concentration increased about 3 time in 4 days. • Stagnant patterns with EH cases are affected by the North Atlantic forcing. • North Atlantic anticyclonic anomaly forcing is developed by a vorticity advection. • The EH cases are induced by stagnant pattern through the Rossby wave propagation. In this study, we investigated the daily variability of PM₁₀ concentrations in January in Korea during the past 19 years (2001–2019), as well as the associated atmospheric circulation patterns. The daily PM₁₀ concentrations were classified into three cases: low (L; < 50 μg/m³), high (H; 50–100 μg/m³), and extremely high (EH; ≥ 100 μg/m³). We found that the strength of the East Asian winter monsoon influenced the PM₁₀ variability in the L and H cases. However, the EH cases were strongly influenced by the rapid growth of barotropic warming (anticyclonic anomaly) over the eastern North Atlantic and Northern Europe (ENE), and the stationary Rossby waves grew rapidly over Eurasia within only four days. Analysis of the quasi-geostrophic geopotential tendency budget revealed that the anticyclonic anomaly over the ENE was enhanced by vorticity advection. Linear baroclinic model experiments confirmed that vorticity forcing over the ENE induces favorable atmospheric conditions for the occurrence of EH PM₁₀ events in East Asia. As a result, the PM₁₀ concentration sharply increased sharply by approximately three times over four days. This study suggests that understanding atmospheric teleconnections between the ENE and East Asia can effectively predict the occurrence of EH PM₁₀ events in Korea, helping to reduce the human health risks from atmospheric pollution.