Smokers, and those with Asthma and COPD, have reduced airflow ability. People who suffer from asthma and COPD show decreases in exhaled air due to inflammation of the airways. This inflammation causes narrowing of the airways which allows less air to be exhaled. Numerous things cause inflammation; some examples are cigarette smoke and environmental interactions such as allergies, weather, and exercise. In smokers the inability to exhale fully is due to the loss of elasticity in the lungs. Smoke in the lungs causes them to harden and become less elastic, which prevents the lungs from expanding or shrinking as they normally would.