About 25 million people in the U.S. — roughly eight out of 100 — are diagnosed with asthma. Allergens, air pollution, extreme weather conditions, or other irritants can cause chronic lung inflammation, leading to coughing, wheezing, or shortness of breath.

About 25 million people in the U.S.—roughly eight out of 100—are diagnosed with asthma. Allergens, air pollution, extreme weather conditions and other irritants can cause chronic lung inflammation, leading ...