Foreseeable Co-occurring O₃ and PM_2.5 Pollution in Eastern China Driven by Climate Teleconnections

The co-occurrence of surface ozone (O₃) and particulate matter (PM_2.5) pollution (COP) has been frequently observed in China, particularly in the North China Plain (NCP) during warmer months, posing significant threats to human health and ecosystems. However, the impact of climate factors on COP remains inadequately understood. This study identifies three major modes of interannual variability in the COP frequency in Eastern China, revealing a consistent spatial pattern, a North-south dipole, and heightened sensitivity in coastal regions. These modes are linked to preseasonal cooling sea surface temperatures (SSTs) in the Western Pacific Ocean, Arctic sea ice (SI) loss near the Barents Sea, and North Atlantic tripole SST anomalies associated with the North Atlantic Oscillation, respectively. Both observations and model simulations confirm that Western Pacific cooling suppresses the Western Pacific subtropical high, promoting pollutant accumulation in the NCP; Barents Sea SI loss triggers atmospheric wave trains, facilitating water vapor transport to southern China and air pollutants transport to Northern China, resulting in a North-south dipole in COP frequency; and North Atlantic Oscillation (NAO)-driven SST anomalies generate westerly wind anomalies, driving pollutants to coastal regions of Eastern China. A model that incorporates preseasonal SST and SI signals is demonstrated to be capable of predicting COP frequency three months in advance. Our results could allow the Chinese government to improve plans for pollution control and safeguard the health of both humans and ecosystems.