Some damage may be permanent while other cases may recover after a long period. For example, methane is reputed to have a residence time of ten years, which means that it stays suspended in the atmosphere for such a period before it changes form. In addition to gases, there are many particles in the atmosphere. These particles are called aerosols, and they can be solid or liquid. There are many sources of atmospheric aerosols.
Wind picks up dust from the surface and carries it into the atmosphere.
Small saltwater drops thrown into the air from ocean waves eventually evaporate and leave behind microscopic salt particles suspended in the air. Smoke from fires is a common source of atmospheric aerosol. Volcanoes may erupt tons of fine ash particles into the atmosphere. Gases such as sulfur dioxide may combine with water in the atmosphere to form tiny droplets of sulfuric acid. It is good that there are some aerosols in the atmosphere because they can act as surfaces on which water vapor condenses to form clouds and eventually produce rain.