Particulate Pollution Increases Fog Duration Over the Indo‐Gangetic Plain

Abstract Observations show increasing trends in wintertime fog episodes and aerosol loading over India. However, whether aerosols affect the fog trends and, if so, through what mechanisms remains unclear. Using long‐term observations, we find that aerosols substantially intensify the nighttime fog and lead to a 36% increase in fog duration in India. Aerosol‐coupled simulations show that high aerosols activate more fog droplets during the formative stages and increase the longwave cooling. Cooling affects supersaturation and enhances the condensational growth of the fog droplets. This aerosol‐longwave cooling‐condensational growth relationship enhances fog water content during nighttime. The subsequent morning, intense fog and aerosol‐radiative effects reduce incoming radiation and promote stagnation under high aerosol loading, delaying fog dissipation. Our study illustrates the aerosol‐cloud interactions induced fog intensification and aerosol's potential role in manifesting the observed fog trends over Indo‐Gangetic Plain, North India.