Sierra Leone West Africa is changing rapidly. An explosively growing population, massive urbanization, and unregulated deforestation modify the composition of the atmosphere, thus affecting weather and climate. The European Union funded research project has said that the air over the coastal region of West Africa is a unique mixture of various trace gases, liquids, and particles. The sources of these particles Professor Peter Knippertz says are monsoon winds with sea salt from the South, Sahara winds with dust from the North, charcoal fires and burning rubbish in cities as well as power plants, ship traffic, oil rigs, and outdated engines. The report mentioned Sierra Leone as one country that the charcoal burning is affecting the weather and climate and it is disrupting the weather pattern always. Also clearing the bushes for farm cultivation is another fire that the report says is causing problems for Sierra Leone. At the same time, multi-layered cloud covers frequently form in the atmosphere and strongly influence local weather and climate. The composition of the particles in the air and what impact they have on the formation and breakup of clouds has not yet been studied in detail. This information is not included in the weather and climate models presently used. The EU-funded project DACCIWA (Dynamics-aerosol-chemistry-cloud Interactions in West Africa) investigates the relationship between weather, climate, and air pollution. For the first time, a coordinated measurement campaign was launched recently to study the entire chain of impacts of natural and anthropogenic emissions on the West African atmosphere. In June and July, three research aircraft, the Falcon of the German Aerospace Center (DLR), the Twin Otter propeller plane Ice Cold Katy of the British Antarctic Survey, and the ATR of the Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE) of the French research institution CNRS, Météo France, and CNES, flew targeted missions over West Africa. The different aircraft were used in different ways based on their strengths, but all three had a comparable instrumentation generating a rich set of reference data. Air pollution does not stay where it is produced, but extends inland by up to 300 km. For this reason, the aircraft followed the plumes of the big coastal cities of Accra, Sierra Leone, Abidjan, Lomé, and Cotonou on their way from the coast towards the inland forests, savannahs, and the Sahara. The particles from these fires lead to a considerable haziness in the atmosphere. Less sunshine reaches the ground, thereby changing the daily patterns of temperature, wind, and clouds. For the first time, the measurements show an enormous complexity in the different cloud layers, the causes of which are still unclear. Moreover, the air particles modify the formation of clouds and raindrops in the clouds. Until 2018, the researchers will continue to study the impacts of atmospheric composition on cloud formation and air quality in West Africa, to evaluate the data measured, and to develop a new generation of climate and weather models. Work is also aimed at making more precise prognoses for West Africa, as strong impacts of climate change, such as water scarcity, heat waves or floods, are to be expected. Better prognoses will also be of benefit to other regions. We know, for instance, that West African monsoon interacts with the Indian monsoon and it is an important factor influencing Atlantic hurricanes, Knippertz says.