Indoor air pollution, especially involving exposure to smoke from biomass fuel, has been determined to be a cause of COPD. Biomass fuel includes burning wood, charcoal, vegetable matter, and animal excrement for energy. Biomass fuel is frequently used in lower-income countries and in poorer areas of developed countries to cook food. Biomass fuel has inefficient combustion and produces smoke that consists of nitrogen dioxide, carbon monoxide, sulfur dioxide, formaldehyde, and other pollutants and carcinogens.[1]
Other airborne pollutants associated with COPD include occupational toxic gasses, grain dust in farms, and factory dust and fumes. Specific occupational exposures associated with COPD include coal and rock mining, transportation and trucking, beauty care (e.g. nail salon), as well as manufacture of plastic, textile, rubber, concrete, and leather. Farming with livestock (chicken, cows, etc.) seems to have a stronger association with COPD than crop farming. This may be because livestock farming increases exposures to ammonia, hydrogen sulfide, and various organic and inorganic dust.[1]