Via scattering and absorption of solar radiation, aerosols can strongly alter the meteorology in the planetary boundary layer (PBL). Both aerosol scattering and absorption reduce the amount of solar radiation reaching the ground and thus reduce the sensible heat fluxes that drive the diurnal evolution of the PBL. Moreover, aerosols can increase atmospheric stability by inducing a temperature inversion as a result of both scattering and absorbing of solar radiation, which suppresses dispersion of pollutants and leads to further increases in aerosol concentration. Such positive feedback is especially strong during severe pollution events. Knowledge of the PBL is thus crucial for understanding the interactions between air pollution and meteorology. A key question is how the diurnal evolution of the PBL interacts with aerosols especially in vertical directions, and affects air quality. We review the major advances in aerosol measurements, PBL processes, and their interactions with each other through complex feedback mechanisms, and highlight the priorities for future studies. In this talk, I will give first give a brief overview of the pertinent processes governing the interaction between aerosol and PBL per a recent review article (Li et al. 2017), and then focused on latest findings concerning the opposite long-term trends in air quality in the lower and upper PBL over regions of strong absorbing aerosols and consistent trends in regions of weak absorbing aerosols (Dong et al. 2017).
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