Environmental pulmonary diseases result from inhalation of dusts, allergens, chemicals, gases, or environmental pollutants. The lungs are continually exposed to the external environment and are susceptible to a host of environmental challenges. Pathologic processes can involve any part of the lungs, including the
Airways (eg, in occupational asthma Occupational Asthma Occupational asthma is reversible airway obstruction that develops after months to years of sensitization to an allergen encountered in the workplace. Symptoms are dyspnea, wheezing, cough,... read more , reactive airways dysfunction syndrome Reactive airways dysfunction syndrome (RADS) and irritant-induced asthma Asthma is a disease of diffuse airway inflammation caused by a variety of triggering stimuli resulting in partially or completely reversible bronchoconstriction. Symptoms and signs include dyspnea... read more , toxic inhalations Irritant Gas Inhalation Injury Irritant gases are those which, when inhaled, dissolve in the water of the respiratory tract mucosa and cause an inflammatory response, usually due to the release of acidic or alkaline radicals... read more , air pollution-related illness Air Pollution–Related Illness The major components of air pollution in developed countries are Nitrogen dioxide (from combustion of fossil fuels) Ozone (from the effect of sunlight on nitrogen dioxide and hydrocarbons) Suspended... read more , or byssinosis Byssinosis Byssinosis is a form of reactive airways disease characterized by bronchoconstriction that occurs in cotton, flax, and hemp workers. The etiologic agent is bacterial endotoxin in cotton dust... read more )
Lung parenchyma (eg, in pneumoconioses Coal Workers’ Pneumoconiosis Coal workers’ pneumoconiosis is caused by inhalation of coal dust. Deposition of dust produces dust-laden macrophages around bronchioles (coal macules), occasionally causing focal bronchiolar... read more , hypersensitivity pneumonitis Hypersensitivity Pneumonitis Hypersensitivity pneumonitis is a syndrome of cough, dyspnea, and fatigue caused by sensitization and subsequent hypersensitivity to environmental (frequently occupational or domestic) antigens... read more , or silicosis Silicosis Silicosis is caused by inhalation of unbound (free) crystalline silica dust and is characterized by nodular pulmonary fibrosis. Chronic silicosis initially causes no symptoms or only mild dyspnea... read more )
Environmental inhalation exposure has long been known to be a risk factor for asthma (see Occupational Asthma Occupational Asthma Occupational asthma is reversible airway obstruction that develops after months to years of sensitization to an allergen encountered in the workplace. Symptoms are dyspnea, wheezing, cough,... read more ), but it is also increasingly being recognized as a non-smoking cause of COPD Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease (COPD) is airflow limitation caused by an inflammatory response to inhaled toxins, often cigarette smoke. Alpha-1 antitrypsin deficiency and various occupational... read more (chronic obstructive pulmonary disease). The American Thoracic Society estimates the population-attributable fraction of COPD related to occupational and environmental exposures to be about 20% (ie, COPD incidence and mortality would decline by about 20% if environmental exposures were reduced to zero).
Clinicians should take an occupational and environmental history in all patients, asking specifically about past and current exposure to vapors, gases, dust, fumes, and/or biomass smoke (ie, from burning wood, animal waste, crops). Any positive response is followed by more detailed questions.
Prevention of Environmental Pulmonary Disease
Prevention of occupational and environmental pulmonary diseases centers on reducing exposure (primary prevention). Exposure can be limited by the use of
Administrative controls (eg, limiting the number of people exposed to hazardous conditions)
Engineering controls (eg, enclosures, ventilation systems, safe clean-up procedures)
Product substitution (eg, using safer, less toxic materials)
Respiratory protection devices (eg, respirator, dust mask, gas mask)
Many clinicians erroneously assume that a patient who has used a respirator or another respiratory protection device has been well protected. Although respirators do afford a degree of protection, especially when fresh air is provided by tank or air hose, the benefit is limited and varies from person to person.
When recommending use of a respirator, clinicians should consider several factors. Workers with cardiovascular disease may be unable to carry out jobs that require strenuous work if they must wear a self-contained breathing apparatus (tank). Respirators that are tight-fitting and that require the wearer to draw air through filter cartridges can increase the work of breathing, which can be especially difficult for patients with asthma, COPD, or interstitial lung diseases.
When a respirator is recommended, patients should undergo yearly adjustments of the respiratory mask to ensure proper fit.
Medical surveillance is a form of secondary prevention. Workers can be offered medical tests that identify disorders early when treatment might help reduce long-term consequences.