For just a starter here is a list of foods, to naturally increase the flavonoids in your diet. Try increasing the foods that agree with you and protect your lungs.
Cocoa, dark chocolate, apples, black grapes, blackberries, black tea, cherries
Garlic, apples, plums, red grapes, citrus fruit, dark cherries and dark berries such as blueberries, blackberries and bilberries, capers, olive oil. Small amounts also found in parsley, sage, elder flower, gingko biloba and St. John's Wort