Atmospheric aerosol spatial variability: Impacts on air quality and climate change

Atmospheric aerosols cause millions of excess deaths per year globally and play a significant role in the climate change problem. Fine and coarse aerosols arise from both natural sources and anthropogenic activities and can be either directly emitted or formed in the atmosphere. Since neither the sources of aerosols nor their secondary formation are distributed evenly around the globe, their concentrations, composition, and characteristics exhibit significant spatial variability. Understanding this spatial variability is essential for deploying successful mitigation strategies that will improve air quality and help minimize climate change. This review summarizes our current understanding and corresponding knowledge gaps regarding the variability of aerosol mass and number concentrations at different scales. Improving existing modeling tools can reduce the uncertainty regarding the magnitude of the effects of aerosols, while remote sensing, low-cost sensors, and international collaboration can bridge the measurement gaps in developing countries and remote areas.