Overview of Environmental Pulmonary Disease
Environmental pulmonary diseases result from inhalation of dusts, allergens, chemicals, gases, and environmental pollutants. The lungs are continually exposed to the external environment and are susceptible to a host of environmental diseases. Pathologic processes can involve any part of the lungs, including the airways (eg, in occupational asthma, reactive airways dysfunction syndrome, or toxic inhalations), interstitium (eg, in pneumoconioses or hypersensitivity pneumonitis), and pleura (eg, in asbestos-related diseases).
Environmental inhalation exposure has long been known to be a risk factor for asthma (see Occupational Asthma), but it is also increasingly being recognized as a non-smoking cause of COPD (see Chronic Obstructive Pulmonary Disease (COPD)). 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 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.
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.