Healthy workers work harder

According to Kreiss, “Cost estimates of productivity loss are substantial, in comparison to the energy cost savings of decreasing ventilation or savings on ventilation system capacity and maintenance housekeeping.”

She added, “Solution of this common problem likely depends upon many disciplines, including architects, general contractors, ventilation engineers, building operations personnel, physicians, industrial hygienists, epidemiologists, and microbiologists. Although specific etiologies have defied scientific documentation, the epidemiological findings to date suggest interventions which should be evaluated in experimental studies, such as lowering respirable particulates, immaculate ventilation systems ductwork maintenance, and housekeeping.”

Cleaner air, not more of it

Increasing ventilation alone does not help. In fact, “In some buildings, operation of the ventilation system resulted in deterioration of subjective air quality, suggesting that ventilation systems could be sources of complaints rather than the solution to them.”

She said maintaining minimum ventilation levels is still important for dilution of suspected indoor pollutants, “as long as the ventilation system is not itself the source of the pollutants.”

This viewpoint should come as good news to those who advocate cleanliness and maintenance of building hvac systems, including duct cleaners. Evidence and support of the effectiveness of these in regard to building IAQ has been scanty, at best.

In fact, the impact of IAQ in general is still questioned by some skeptics. Kreiss points out that “Despite more than two decades of public health investigation of Sick Building Syndrome, scientific research regarding cause and effective intervention or prevention has been meager.”

Ignoring complaints, however, or less-than-effective remediation efforts, she said, often only leads to “nonscientific explanations of [building occupants’] symptoms.”