Carbon dioxide infiltration into a home.
Harrison-J; Rao-C; Benaise-LW
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California. Fairfax, VA: American Industrial Hygiene Association, 2005 May; :61-62
NIOSH received a Technical Assistance request in December 2003 to assist with the investigation of a home built above an abandoned coal mine and on a reclaimed surface mine. The residents reported new-onset shortness of breath, lightheadedness, dizziness, poor concentration and blurry vision while in the basement. Their symptoms resolved within minutes after leaving the basement. Investigators found an oxygen-deficient environment in the basement and crawlspace areas of the home. Carbon monoxide and methane were not detected, which led investigators to suspect that carbon dioxide (CO2) could be displacing oxygen in the basement and crawlspace. A direct-reading CO2 monitor was used for short-term sampling. Concentrations of CO2 were as high as 9.5% in the home's crawlspace, 11% in the crawlspace gravel, and 12% inside a floor drain (outside air was 0.035%). CO2 levels in the living areas of the home were greater than 1% (10,000 ppm). Oxygen concentration in the basement was intermittently deficient, with levels measuring as low as 14% in the crawlspace (normal range = 19.5% and 23.5%). Air and soil gas samples analyzed for carbon isotopic composition indicated that the CO2 infiltrating into the house was likely from a carbonate source. Others have reported similar events in homes built above abandoned coal mines in England, Russia and the U.S. Preventive measures for mining-related indoor air quality problems includes sealing cracks, maintaining positive pressure in relation to the ground, and ventilating subsurface areas in a manner similar to that used for radon mitigation. In affected homes, homeowners, public utility workers, and remediation workers could be overexposed to CO2 and in an oxygen-deficient environment. This dictates efforts to increase public awareness of the potential hazards and to appropriately educate people who may be potentially exposed.
Environmental-factors; Oxygen-deficient-atmospheres; Oxygen-uptake; Sampling; Exposure-levels; Health-hazards; Environmental-hazards; Indoor-air-pollution; Surface-mining; Coal-mining; Indoor-environmental-quality
124-38-9; 74-82-8; 630-08-0
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California