Lung Diseases Due to Gas or Chemical Exposure

Overview :

The lungs are susceptible to many airborne poisons and irritants. Mucus present in the airways blocks foreign particles of a certain size, however it is unable to filter all airborne particulates. There are hundreds of substances that can pollute air and harm lungs. Harmful gases and chemicals are just one type of airborne pollutant that can adversely affect the lungs. They include:

• Vehicle exhaust
• Localized pollutants such as arsenic, asbestos, lead, and mercury
• Outdoor pollutants caused by industry and intensified by weather conditions
• Household heating, such as wood-burning stoves
• Household chemical products
• Tobacco smoke.

Lungs respond to irritants in four ways, each of which can occur separately or, more often, trigger other responses.

• Asthma occurs when irritation causes the smooth muscles surrounding the airways to constrict.
• Increased mucus comes from irritated mucus glands lining the airway. Excess mucus clogs the airway and prevents air from circulating.
• Constriction of the lungs results from scarring when the supporting tissues are damaged.
• Cancer is caused by certain irritants, such as asbestos and tobacco smoke.

The major categories that airborne irritants fall into are allergic, organic, inorganic, and poisonous, with many agents occupying more than one category.

• Allergic irritants bother only people who are sensitive to them. Cat hair, insect parts, and pollen are common allergens. Chemicals called sulfites, which are widely used as food preservatives, also cause asthma.
• There are many organic dusts that irritate the lungs. Most of them occur on the job and cause occupational lung disease. Grain dust causes silo filler's disease. Cotton and other textile dusts cause byssinosis. Mold spores in hay cause farmer's lung.
• Inorganic dusts and aerosolized chemicals also are found mostly on the job. Classic among them are asbestos and coal dust. Many metals (cadmium, arsenic, chromium, and phosphorus), various other fine particles (cement, mica, rock), acid fumes, ammonia, ozone, and automobile and industrial emissions are part of a very long list.
• While tobacco smoke is a culprit in many smokers, a 2003 report found that those who work in the tobacco industry experience higher incidence of lung disease from tobacco dust in their work environment.
• Most intentional poisons (cyanide, nerve gas) that enter through the lungs pass through and damage other parts of the body. Mustard gas, used during World War I and banned since, directly and immediately destroys lungs.
• Tobacco use scars the lungs and causes emphysema and lung cancer.
  
  

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