Making Practical Changes with Present Evidence
	It would be ideal if all indoor exposures were supported by strong scientific evidence that establishes a definite causal link between the exposure and specific health effects. It would also be helpful if such evidence had been reproduced by multiple researchers over time. It would also be comforting if such conclusions had achieved a reasonable degree of medical and scientific acceptance and consensus. Such is not the case, reports a recent Lung Association study (see below). While much of the evidence is compelling, most of it establishes an association between an indoor environmental factor and respiratory illness, and not a confirmed causal connection. While this begs for further research in each area to unearth or confirm the actual causal mechanisms, it does not prevent practical action in the interim which could reduce the incidence of respiratory illness. For example, it will be interesting and useful to ultimately learn the relative role of dust mites, moulds, bacteria, bacterial endotoxins and other agents in respiratory illness associated with dampness in housing. But it is possible without knowing all of the details, to make changes in housing that will avoid, reduce or eliminate dampness, and that will correspondingly reduce the risk of adverse respiratory health associated with it. Likewise, eliminating dampness and extensive fungal exposure in housing would be safer (in terms of unknowns) and likely more effective than eliminating only Stachybotrys chartarum or bacterial endotoxin exposure. In this case, the action would be based on a strong general association (dampness in housing and respiratory illness), but would still assist in protecting people from specific hazards that may only later be proven to have definite causal connection to specific forms of illness. (e.g. Stachybotrys chartarum and pulmonary haemorrhage, bacterial endotoxin and development of asthma). There have been a number of areas highlighted in a report by the Ontario Lung Association (clickable under references below), where remedial measures could improve respiratory health: reduction of dampness in housing and associated mould and bacterial exposures reduction of risk factors for the development of upper respiratory tract infections (which are important in the exacerbation of asthma) reduction of allergen exposures, including dust mites, cockroach antigen and animal dander reduction or elimination of exposure to environmental tobacco smoke avoidance or reduction of exposure to products of combustion reduction or avoidance of unnecessary exposure to products of emission reduction of exposure to particulates, especially PM10 and PM2.5 reduction of exposure to radon and radon progeny through better building design
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	Record #135, revised 6/11/2002

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Primary Sources 1. Indoor Air Pollutants in Residential Settings

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