NIOSH Programs > Respiratory Diseases > Evidence Package > 9. Respiratory Disease HHEs and Technical Assistance
9.2 Building-Related Asthma9.1 Flockworkers Lung Disease | 9.3 Flavoring-Related Lung Disease
Damp indoor environments are associated with respiratory and nasal symptoms, exacerbation of asthma, and hypersensitivity pneumonitis, as detailed in chapter 4.1c. Approximately half of the public’s requests for HETAs concern indoor-air quality, and half of these requests mention asthma and/or chest symptoms. Of HETA requests concerning asthma, two-thirds are attributed by requesters to the indoor environment of non-industrial buildings, with about 55 percent mentioning mold or moisture incursion. The proportion of indoor air quality requests for HETAs mentioning chest symptoms and asthma has increased steadily over the 1980s and 1990s. Despite the evidence for an emerging problem, little research existed to support whether asthma could arise in damp indoor environments. No environmental measurements, apart from observing dampness-associated conditions, had been shown to be useful for risk assessment or assurance of occupant health in particular buildings. These knowledge gaps were documented by a CDC-funded IOM review published in 2004, “Damp Indoor Spaces and Health.”
The substantial public concerns for WRA in non-industrial workers are reflected in estimates of economic consequences of asthma for the indoor workforce of $3.9 to $4.1 billon. Improved indoor environments are estimated to produce $200-$600 million economic benefit for building-related asthma, allergy, and hypersensitivity pneumonitis (2, A9-20), with additional economic benefit possible in the categories of lowering communicable respiratory infection and nonspecific building-related symptoms.
Beginning in October 1999, RDRP staff carefully scrutinized HETA requests concerning building-related asthma that appeared to have a range of dampness and/or buildings in which risk factors for asthma could be evaluated. We conducted investigations of selected buildings and their occupants with a program of “Research on Occupational Asthma Reduction,” which received competitively allocated intramural funds. Our major efforts have been the study of a damp hospital and comparison hospital in Montana; a community college in New York, and a state office building in Connecticut. In each, we conducted questionnaire surveys of employees for health, diagnosis, and job history. In some buildings, we showed that asthma incidence after employees occupied a building had increased seven-fold compared to asthma incidence during adulthood before occupancy, suggestive of a building-related cause of new onset asthma. We conducted environmental assessment using room-specific dampness indices and sampling of dust for biomass measurements as an alternative to the more commonly used short term air sampling for culturable microorganisms, which is not generally associated with health risk. We then linked health outcome data with environmental data. Our studies showed associations between endotoxin and 1-3,B,D-glucans (a mold cell wall constituent) exposures and risk of work-related symptoms of respiratory disease. We also showed that remediation of one building with a history of water incursion problems failed to decrease building-related symptoms in persons whose symptoms had started prior to remediation.
Outputs and Transfer
The reports of our HETAs in specific workplaces document building-related asthma as a phenomenon and recommend remediation of dampness. To generalize our findings, results have been published in peer-reviewed journals. These publications have filled a need in the international indoor air research community for damp building case studies with sophisticated environmental characterization, medical testing, and longitudinal study of remediation (3-5, A4-31, A4-32, A9-21).
RDRP HETA applied research has motivated animal model work on glucan, fungal fragments, and dusts from particular buildings; and design of bioaerosol samplers amenable to biomass measurements. Our staff played an organizing role in the 2005 Surgeon General’s Conference on Healthy Indoor Environment.
Health data generated in HETAs of particular building populations have motivated secondary prevention by relocating affected persons in some buildings and primary prevention by remediation of sources of moisture incursion. The degree of remediation required for primary and secondary prevention remains under longitudinal study. Further studies of measures of biomass and dampness assessment predicting health risk, along with showing the long term effectiveness of remediation will strengthen the public health resolve to declare damp indoor spaces a public health problem.
Based on previous work evaluating relationships between indoor air quality and asthma, competitive intramural funding has been obtained for a new 2006-2010 research initiative on the effectiveness of building remediation to improve the health of employee occupants. This work will be conducted in a previously-studied Connecticut office building and in the state of Maine’s public school system. We will assess the effects of remediation of building dampness on both biomass and chemical exposures and on respiratory health of building occupants.
We will also continue to perform short-term evaluations of indoor environments identified through the HETA program as potential sentinels of emerging issues and respond to HETA requests that involve areas needing study such as air-borne infectious disease transmission in the indoor environment.