Enhanced haze pollution by black carbon in megacities in China

Aerosol‐planetary boundary layer (PBL) interactions have been found to enhance air pollution in megacities in China. We show that black carbon (BC) aerosols play the key role in modifying the PBL meteorology and hence enhancing the haze pollution. With model simulations and data analysis from various field observations in December 2013, we demonstrate that BC induces heating in the PBL, particularly in the upper PBL, and the resulting decreased surface heat flux substantially depresses the development of PBL and consequently enhances the occurrences of extreme haze pollution episodes. We define this process as the “dome effect” of BC and suggest an urgent need for reducing BC emissions as an efficient way to mitigate the extreme haze pollution in megacities of China. Key Points BC plays an important role in enhancing surface haze pollution in megacities in China Upper PBL heating and surface cooling by BC are two comparable processes in the PBL feedback Reducing BC emission cobenefits the mitigations of haze pollution and global warming