One characteristic of aerosols is their Aerosol Optical Thickness (AOT), which is an indication of the transparency of the atmosphere (see and is related to the amount and type of aerosols present in the atmosphere.

This animation shows the simulated AOT of five different aerosols over the course of the year as simulated by the atmospheric chemistry general circulation model EMAC ( The model includes natural aerosols (e.g. sea salt and dust) together with aerosols more connected to human activities (e.g. sulfate/nitrate).


The animation shows the AOT during the years 2010 and 2050. The AOT for the year 2050 is estimated only considering anthropogenic emission changes. The emission scenario assumes that population and economic growth largely determine energy and food consumption and consequent pollution sources with the current technologies (“business as usual”).  This scenario is chosen to show the effects of not implementing legislation to prevent additional climate change and growing air pollution, other than what is in place for the base year 2005, representing a pessimistic (but plausible) future.

Information on the model can be found here:

Information on the simulations used for the visualization can be found here:

Pozzer, A., Zimmermann, P., Doering, U.M., van Aardenne, J., Tost, H., Dentener, F., Janssens-Maenhout, G., and Lelieveld, J.:  Effects of business-as-usual anthropogenic emissions on air quality, Atmos. Chem. Phys., 12, 6915-6937, doi:10.5194/acp-12-6915-2012, 2012

Pozzer, A., de Meij, A., Pringle, K. J., Tost, H., Doering, U. M., van Aardenne, J., and Lelieveld, J.: Distributions and regional budgets of aerosols and their precursors simulated with the EMAC chemistry-climate model,  Atmos. Chem. Phys., 12, 961-987, doi:10.5194/acp-12-961-2012, 2012

and directly at the MPI for Chemisty: