Indoor Air Quality Diagnostics: Qualitative and Quantitative Procedures to Improve Environmental Conditions

Abstract

Procedures conventionally used in industrial hygiene are often inappropriate for application in non-industrial environments. More sensitive procedures are needed, since comfort, occupant well-being, and general population susceptibilities are parameters not now addressed by occupational threshold limit values (TLVs). A common result is that compliance with industrial hygiene standards may be demonstrated, but complaints from occupants persist. A new discipline, building diagnostics, is useful in addressing these more sensitive parameters. An application of this discipline to the evaluation of indoor air quality is presented in this paper. A fundamental aspect to building diagnostics is the need to understand the relationships that exist between the building, its systems, and its occupants. This understanding is developed initially through qualitative diagnostics in which the scope of investigation is defined, appropriate environmental performance criteria are determined, the nature of any existing complaints is reviewed, and an engineering assessment of the HVAC system is conducted. From these qualitative data, a set of hypotheses is developed in terms of the inadequacies of the performance or the opportunities for improvement. Based on these hypotheses, system performance under various loads is predicted and ways to mitigate and improve performance are recommended. An important advantage of this approach is that many problems can be solved at this stage before measured data are required. However, in some cases, objective and subjective measurements may be required to confirm hypotheses and to substantiate or modify the previous recommendations. In these cases, quantitative diagnostics is indicated. Because of the cost involved in this phase, measurement locations must be identified carefully. We find that five locations in a functional area of the building are sufficient to characterize system performance and occupant response: locations of least ventilation effectiveness, strongest contaminant source, most susceptible occupants, a “control location,” and an outdoor location. Only those quantitative measurements appropriate to the hypotheses are taken; these may include air quality, thermal, lighting, and acoustics parameters. Simultaneously, questionnaires are also used to measure human responses to the environmental conditions within the occupied spaces. These quantitative data are analyzed for compliance with the performance criteria. Recommendations for modifications are then made which address employee concerns, architectural concerns, and cost-effective operation.

Relationships Between Ventilation and Indoor Air Quality: A Review

“…The premise that inadequate ventilation is the primary cause of building air quality complaints forms the basis of investigative protocols widely used in the United States by a number of private consulting companies. "Healthy buildings" are described as those buildings which meet various performance criteria (particularly ventilation) while "unhealthy" or "sick" buildings do not (Woods et al, 1987;Lane et al, 1989).…”

The significance of air pollution in aerobiology

“…It has been related epidemiologically to sealed buildings, increased temperature and dust levels, passive cigarette smoking, psychogenic or social factors. Bioaerosols may be responsiblc, though mostly for true building-related illness (Woods et al 1989). Buildings with humidifiers and chillers have more symptomatic workers than buildings without (Finnegan ct al.…”

“…The combined effect of all contaminants, especially infectious agents and those indoors, is thought to account for a substantial proportion of absenteeism in schools and workplaces, and of days of restricted activity or performance, 5-15 days of re- Sampling protocols have to address the potential spatial and temporal distribution of the agents, andlor the health effects (NRC 1981, Woods et al 1989. Burge 1989, WHO 1983.…”