The lungs are crucial to our well being because they ensure the steady flow of oxygen into the body and also the steady flow of carbon dioxide out of the body. However, various particulates in the air can easily muck up lungs, decreasing their overall function. While the lungs do have a natural form of cleansing themselves with their cilia (which catches bacteria and dust particles, and then forces them out of the lungs through mucus), you can try various activities and home remedies to help purify your lungs.
Drink a lot of water. Water is always a crucial factor in helping purify the body, and the lungs are no exception. Water will help flush your lungs of various poisons and undesirable elements by forcing them out of the lungs and out of your body through urine.
Eat garlic. Garlic helps you exfoliate poisons from the lungs through your skin pores, and has the additional effect of clearing your sinus cavities because it will force mucus out. Clear sinus cavities are important to purifying lungs because it allows for additional mucus to come out from the lungs, and mucus is the medium of transport that the lungs use to get rid of unwanted particulates. Horseradish and ginger can also be used similarly to garlic.
Avoid irritants. The lungs are an exceptionally resilient set of organs; in a healthy environment they can purify themselves in a short period of time. By removing yourself from potential irritants (such as second hand smoke, car exhaust or pollen) for a period of a few days, you can give your lungs an opportunity to naturally purify.
Consult with a licensed medical professional if you fear that your lungs are not working properly.
Garlic and other spices have not been proven scientifically as remedies for purifying the lungs; they are holistic cures and should be treated as such.