How long does it take to get healthy lungs after you quit smoking?

Many benefits ...: Benefits to giving up smoking: within 20 mins, blood pressure and heart rate decrease; within 12 hrs, carbon monoxide blood levels normalize; within 48 hrs, the sense of smell and taste start recovering; within 3 mos, circulation and lung function improve; within 9 mos, there is less coughing and shortness of breath; within 1 yr, the risk of coronary heart disease is cut in half. Need i say more?