“…Especially over the last two decades when the MODerate resolution Imaging Spectroradiometer (MODIS) and Multiangle Imaging SpectroRadiometer (MISR) instruments started orbiting Earth, a wealth of information has become available, which helped us promote our understanding of aerosol occurrence and evolution in the Earth's atmosphere (Alfaro-Contreras et al, 2017;Fan et al, 2018;Hu et al, 2018;Levy et al, 2010Levy et al, , 2013Levy et al, , 2015Oikawa et al, 2018;Sayer et al, 2014). Through those studies, the emission-control measures that led to the cleaning of air over the United States and Europe, together with the pollution increase that followed the explosion of industrial activity in South and East Asia, quickly became apparent (Adesina et al, 2016;Aklesso et al, 2018;Arkian & Nicholson, 2017;Boiyo et al, 2018;Floutsi et al, 2016;Gopal et al, 2016;He et al, 2016;Jongeward et al, 2016;Kumar et al, 2018;Mehta et al, 2018;Shokr et al, 2017;Wang et al, 2017Wang et al, , 2016Xu et al, 2015). As such satellite-retrieved aerosol optical depth (AOD) can be used for trend studies, changes in clear-sky shortwave radiative fluxes constrained by the observed variability in outgoing shortwave radiation from the Clouds and the Earth's Radiant Energy System (CERES) can be used to look at radiative flux trends over the past two decades (Paulot et al, 2018).…”