a solution that relates to chemistry for air pollution:
carbon dioxide CO2 is an air pollutant related to global warming. one solution to reduce the amount of CO2 is to freeze it into solid. The solid, called dry ice, will then be stored near the north and south pole to keep cold. that way there will be less CO2 in air to cause global warming.
the above is a physical change. there are also other discussions in using different chemicals to react with CO2 in air. the idea is the same: by removing CO2 thro. chemical reaction, it can be removed n stored.