Chronic Obstructive Pulmonary Disease or COPD is a general term used to describe a combination of lung diseases. COPD (in the United States) most commonly includes two major diseases, emphysema and chronic bronchitis. COPD is a progressive disease that gets worse over time. There is no known cure for COPD, but treatments are available to maintain quality of life. Chronic obstructive pulmonary disease causes coughing fits that produce large amounts of phlegm when the bronchioles become clogged with mucus. “COPD is not simply 'smoker's cough,' but an underdiagnosed and life-threatening lung disease.” (As stated by the WHO, World Health Organization). Chronic obstructive pulmonary disease affects more than 60 million people worldwide. In 2005 alone, more than 3 million people died from COPD. (2005, WHO) Those most at risk are smokers, women, especially where biomass fuel is used in the home, miners, those with a history of asthma and people who are unemployed, on low income, divorced, separated or widowed . Two of the things most widely exchanged under the term COPD are emphysema and chronic bronchitis. These are completely different diseases with their own diagnosis. Although most healthcare organizations classify them as COPD or COPD-related, some institutions do not. Chronic bronchitis is inflammation and irritation of the lining of the airways (bronchi and bronchioles). The irritation caused by chronic bronchitis causes an overproduction of mucus, producing blockages within the bronchi and bronchioles. Coughing up thick mucus is a common occurrence in people with chronic bronchitis. The phlegm produced will often be discolored, yellow or brownish, green or even clear, and will usually be darker and thicker in the center of the paper...... phone booth (body plethysmograph) during inhalation and out into a mouthpiece. Pressure changes within the box help determine lung volume. Lung volume can also be measured when you breathe nitrogen or helium through a tube for a period of time. The concentration of gas in a chamber connected to the tube is measured to estimate lung volume. To measure diffusion capacity, you breathe a harmless gas, called tracer gas, for a very short time, often for just one breath. The concentration of the gas in the air you exhale is measured. The difference in the amount of gas inhaled and exhaled measures how effectively the gas passes from the lungs into the blood. This test allows your doctor to estimate your lungs' ability to move oxygen from the air into your bloodstream. http://www.goldcopd.org/uploads/users/files/GOLD_Report_2011_Feb21.pdf