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 (see also Defense Mechanisms of the Respiratory System Defense Mechanisms of the Respiratory System The average person who is moderately active during the daytime breathes about 20,000 liters (more than 5,000 gallons) of air every 24 hours. Inevitably, this air (which would weigh more than... read more ). 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 Asbestosis Asbestosis is widespread scarring of lung tissue caused by breathing asbestos dust. Asbestosis causes shortness of breath and a decreased ability to exercise. Diagnosis is usually made with... read more or silica Silicosis Silicosis is permanent scarring of the lungs caused by inhaling silica (quartz) dust. People develop difficulty breathing during exercise that sometimes progresses to shortness of breath even... read more ).
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 Overview of Idiopathic Interstitial Pneumonias Idiopathic interstitial pneumonias are interstitial lung diseases that have no known cause that have some similarities in symptoms and how they affect the lungs. Some types of these diseases... read more ). 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:
Some people, particularly those with other lung disorders, are at risk when they are exposed to air pollution in the environment ( see Air Pollution–Related Illness Air Pollution–Related Illness Illnesses related to air pollution are considered environmental lung diseases. (See also Overview of Environmental Lung Diseases.) The major components of air pollution in developed countries... read more ) or to contaminants in indoor environments ( see Building-Related Illnesses Building-Related Illnesses Building-related illnesses are disorders that affect the lungs as well as other parts of the body and are caused by exposure to substances within modern airtight buildings. Building-related... read more ).
Many more people are at risk of occupational asthma Occupational Asthma Occupational asthma is a reversible narrowing of the airways caused by inhaling work-related particles or vapors that act as irritants or cause an allergic reaction. Occupational asthma may... read more as a result of exposure in the workplace.
Exposure to asbestos can cause asbestosis Asbestosis Asbestosis is widespread scarring of lung tissue caused by breathing asbestos dust. Asbestosis causes shortness of breath and a decreased ability to exercise. Diagnosis is usually made with... read more , mesothelioma Mesothelioma Mesothelioma is cancer of the thin, transparent, two-layered membrane that covers and lines the inside of the chest wall and abdomen. The most common symptoms are persistent chest pain and shortness... read more , and asbestos-related pleural disease Asbestos-Related Pleural Disease Asbestos is a family of naturally occurring compounds whose heat-resistant and structural properties made it useful for inclusion in construction and shipbuilding materials, automobile brakes... read more .
People who work with beryllium, such as aerospace workers, are at risk of beryllium disease Beryllium Disease Beryllium disease is a lung inflammation caused by inhaling dust or fumes that contain beryllium. Most people with beryllium disease have gradual development of coughing, difficulty breathing... read more .
People who work with cotton, flax, or hemp are at risk of byssinosis Byssinosis Byssinosis is a narrowing of the airways caused by inhaling cotton, flax, or hemp particles. Byssinosis may cause wheezing and tightness in the chest, usually on the first day of work after... read more .
Coal workers and graphite workers are at risk of coal workers’ pneumoconiosis Coal Workers’ Pneumoconiosis Coal workers’ pneumoconiosis is a lung disease caused by deposits of coal dust in the lungs. People generally have no symptoms, but people who have severe disease cough and become short of breath... read more .
Exposures to gas and chemicals may occur at work (for example in farmers) or in the home ( see Gas and Chemical Exposure Gas and Chemical Exposure Symptoms depend on which gas or chemical is inhaled and how deeply and for how long it was inhaled. Symptoms may include irritation of the eyes or nose, cough, blood in the sputum, and shortness... read more ).
In people who already have lung diseases such as chronic obstructive pulmonary disease Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease is persistent narrowing (blocking, or obstruction) of the airways occurring with emphysema, chronic obstructive bronchitis, or both disorders. Cigarette... read more or asthma Asthma Asthma is a condition in which the airways narrow—usually reversibly—in response to certain stimuli. Coughing, wheezing, and shortness of breath that occur in response to specific triggers are... read more , exposure to substances in the environment may cause worsening symptoms even if the substance itself does not cause lung disease.
Symptoms of Environmental Lung Diseases
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. For some disorders (for example, coal workers’ pneumoconiosis Coal Workers’ Pneumoconiosis Coal workers’ pneumoconiosis is a lung disease caused by deposits of coal dust in the lungs. People generally have no symptoms, but people who have severe disease cough and become short of breath... read more ), the symptoms may not occur immediately and may develop over months to years. 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 (exacerbations) 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.
Diagnosis of Environmental Lung Diseases
Lung function tests
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 Pulmonary Function Testing (PFT) Pulmonary function tests measure the lungs' capacity to hold air, to move air in and out, and to absorb oxygen. Pulmonary function tests are better at detecting the general type and severity... read more and imaging tests such as chest x-rays and computed tomography (CT) are used in most cases.
Prevention of Environmental Lung Diseases
Prevention of occupational and environmental lung diseases, particularly in the workplace, include steps to limit exposure, including
Administrative controls, such as limiting the number of people exposed
Engineering controls, such as use of ventilation systems, enclosures, and safe clean-up procedures
Product substitution, such as use of safer materials
Protective devices, such as use of respirators, dust masks, and other equipment
Educational controls, such as teaching workers about risks and how to limit exposure
Respirators and other measures do provide some protection; however, protection may not be complete and the protection varies from person to person. Respirators need to be checked once per year to ensure proper fit. 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 Pulmonary Function Testing (PFT) Pulmonary function tests measure the lungs' capacity to hold air, to move air in and out, and to absorb oxygen. Pulmonary function tests are better at detecting the general type and severity... read more and measuring the amount of oxygen in the blood Arterial Blood Gas (ABG) Analysis and Pulse Oximetry Both arterial blood gas testing and pulse oximetry measure the amount of oxygen in the blood, which helps determine how well the lungs are functioning. Arterial blood gas tests are invasive... read more . Imaging of the lungs Chest Imaging Chest imaging studies include X-rays Computed tomography (CT) CT angiography Magnetic resonance imaging (MRI) read more using chest x-rays or computed tomography (CT) may also be done.