Environmental lung diseases are caused by harmful particles, mists, vapors, or gases that are inhaled, usually while people work. If the lung disease is due to inhaled particles, the term pneumoconiosis is often used. Where within the airways or lungs an inhaled substance ends up and what type of lung disease develops depend on the size and kind of particles inhaled. Large particles may get trapped in the nose or large airways, but very small ones may reach the lungs. There, some particles dissolve and may be absorbed into the bloodstream. Most solid particles that do not dissolve are removed by the body's defenses.
The body has several means of getting rid of inhaled particles. In the airways, an accumulation of secretions (mucus) coats particles so that they can be coughed up more easily. Additionally, cells lining the airways have tiny filaments called cilia that stick out into the airways, and these filaments can brush inhaled particles upward, out of the lungs. In the small air sacs of the lungs (alveoli), special scavenger cells (macrophages) engulf most particles and render them harmless.
Many different kinds of particles can harm the lungs. Some are organic, meaning that they are made of materials that contain carbon and are part of living organisms (such as grain dusts, cotton dust, or animal dander). Some are inorganic, meaning that they usually come from nonliving sources, such as metals or minerals (for example, asbestos).
Risk of environmental lung disease:
Different types of particles produce different reactions in the body. Some particles—animal dander, for example—can cause allergic reactions, such as hay fever–like symptoms or a type of asthma. Other particles cause harm not by triggering allergic reactions but by being toxic to the cells of the airways and air sacs in the lung. Some particles, such as quartz dust and asbestos, may cause chronic irritation that can lead to scarring of lung tissue (pulmonary fibrosis—see Overview of Idiopathic Interstitial Pneumonias). Certain toxic particles, such as asbestos, can cause lung cancer, especially in people who smoke, or cancer of the lining of the chest and lung (mesothelioma), regardless of the person's smoking history.
The specific type of environmental lung disease depends on the environment to which the person is exposed:
In people who already have lung diseases such as chronic obstructive pulmonary disease or asthma, exposure to substances in the environment may cause worsening symptoms even if the substance itself does not cause lung disease.
Environmental lung diseases tend to cause symptoms similar to those of many other lung disorders, such as difficulty breathing and sometimes cough or chest pain. Environmental lung diseases that make the lungs and airways narrow when a person breathes air that contains irritants and other substances (called airway hyperreactivity) may cause difficulty breathing that is sudden, wheezing, and, in people who have asthma or COPD, attacks of those disorders.
Environmental lung disorders that cause repeated, chronic problems increase the risk of developing chronic lung disorders (such as COPD or interstitial lung disorders) and permanently decreasing lung function. Some environmental lung disorders cause other symptoms and complications.
Specific diagnostic tools are used to identify environmental lung diseases. As the initial step in the evaluation, the doctor asks about jobs and other activities that may be associated with exposure to lung irritants. Tests of lung function (see Pulmonary Function Testing (PFT)) and imaging tests are used in most cases.
Prevention of occupational and environmental lung diseases include steps to limit exposure, including
Respirators and other measures do provide some protection; however, protection may not be complete and the protection varies from person to person. Also, not all people can easily use protective measures. For example, respirators may limit the ability of people with heart or lung disorders to carry out job functions.
Doctors encourage people who may be exposed to substances that can damage the lungs to be screened regularly so that disorders can be identified as early as possible. Specific screening tests and the frequency of the screening depend on the substances to which the person is exposed. Screening can include medical examinations and measuring the person's breathing using spirometry (see Pulmonary Function Testing (PFT)) and measuring the amount of oxygen in the blood (see Arterial Blood Gas (ABG) Analysis). Imaging of the lungs using chest x-rays or computed tomography (CT) may also be done (see Chest Imaging).
Last full review/revision January 2015 by Lee S. Newman, MD, MA