Any substance that is breathed in affects what happens to the lungs. Many of these substances can be hazardous and threaten the lungs' ability to work properly. Such hazards may include:
- Cigarette Smoking - The major cause of chronic obstructive pulmonary (note the term pulmonary refers to the lungs) disease (COPD) and lung cancer is cigarette smoking. When someone inhales cigarette smoke, irritating gases and particles cause one of the lungs' defenses - the cilia - to slow down. Even one puff on a cigarette slows the cilia, weakening the lungs' ability to defend themselves against infections. Cigarette smoke can cause air passages to close up and make breathing more difficult. It causes chronic inflammation or swelling in the lungs, leading to chronic bronchitis. And cigarette smoke changes the enzyme balance of the lungs, leading to destruction of lung tissue that occurs in emphysema. Macrophages - scavenger cells in the lungs - are also impaired.
- Triggers of Asthma - Asthma, the temporary blocking of the small passages of the lungs, has many possible triggers and can be life-threatening. Infections, lung irritants, cold weather, allergies, overexertion, excitement, inherited factors, even workplace chemicals and other irritants, play a part in this disease.
- Tuberculosis (TB) - Tuberculosis is caused by a bacterium spread by the coughing or sneezing of a person who has active TB germs in his or her phlegm (sputum). Most people who develop TB today were infected years ago when the disease was widespread. Years or decades later, if the natural defense systems of people's bodies begin to weaken, the barriers they built up around the germs begin to crumble, and the TB germs escape and multiply. Such waiting-to-attack infection can become real illness when a person's defenses are weakened by HIV (Human Immunodeficiency Virus) infection or other illnesses such as cancer.
- Occupational Hazards - Substances you breathe at work can cause lung trouble, too. Workers who are exposed to occupational hazards in the air - dusts like those from coal, silica, asbestos, or raw cotton and metal fumes or chemical vapors - can develop lung disease, including occupational asthma.
- Virus, Fungus, Bacterium (other than TB) - Hundreds of germs like these are carried in the air at all times. If they are inhaled into the lungs, the germs can cause colds, influenza, pneumonia, and other respiratory infections. When these germs lodge in your lungs, your breathing patterns can be disrupted, and you can become ill. Some of these illnesses can be prevented with vaccination.
- Air Pollution - Particles and gases in the air can be a source of lung irritation. Do whatever you can to reduce your exposure to air pollution. Refer to radio or television weather reports or your local newspaper for information about air quality. On days when the ozone (smog) level is unhealthy, restrict your physical activity to early morning or evening because smog is increased in sunlight. When pollution levels are dangerous, limit activities as necessary. People with chronic heart and lung disease should remain indoors.