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INDOOR ENVIRONMENTAL QUALITY​
NIOSH Advises College to Review Ventilation in ​Response to IEQ Complaints​​
In a recent health hazard evaluation (HHE) report, NIOSH describes an investigation of indoor environmental quality (IEQ) conditions in a college campus building that housed offices, classrooms, and a dental clinic. The HHE was requested by an employer representative who notified the agency that employees were concerned about perceived poor IEQ in the building. NIOSH had evaluated the building on two previous occasions. In 1982, agency investigators found no substances in the building that were capable of causing the symptoms involving the nervous system that employees had reportedly experienced. A second investigation in 1998 again found no sources in the workplace that could have been responsible for employees’ symptoms, which included nausea, headaches, burning eyes, and chronic respiratory problems. Between 2001 and 2013, independent IEQ consultants performed several investigations of the building. A 2001 report concluded that all areas of the building required mold remediation and recommended upgrading the ventilation system. Mold remediation concluded in 2002, and the ventilation system was replaced in 2011, but employees continued to voice concerns about IEQ and report symptoms such as headaches, eye and throat irritation, poor memory, lightheadedness, and nausea. The most recent NIOSH investigation was conducted in May 2013. Agency personnel found no evidence of past or current water damage, water entering the building, or mold during their walk-through survey. Though the ventilation system appeared well maintained and functioned as designed, NIOSH identified two conditions that could lead to airborne contaminants from the dental clinic spreading to other parts of the building. According to the report, return air from the dental clinic was mixing with return air from offices and classrooms before being recirculated, and the dental clinic was not kept under a consistent neutral or negative air pressure relative to surrounding areas of the building. NIOSH staff also found one uncapped plumbing vent in a cabinet in the dental laboratory.
“We believe that care must be taken when attributing common symptoms to particular exposures because the association is as likely to be coincidental as to be causal,” the report notes.
NIOSH personnel conducted interviews with building occupants as part of their evaluation. Most interviewed occupants reported “nonspecific symptoms common to workplaces and in the general population.” NIOSH staff did not identify current problems with the building that could be associated with employees’ symptoms. The NIOSH report recommends that the college consult with a ventilation engineer to review the building’s ventilation system design for possible improvements, and to stop environmental sampling for chemical and biological agents, which had been ongoing over the past 13 years. NIOSH also recommends that employees using portable ionizing air cleaners should stop use because the devices may release ozone, which can cause symptoms similar to those reported during the interviews. The report discusses the possibility that the symptoms reported by employees at the building were influenced by the building occupants’ heightened awareness of suspected IEQ problems. Research indicates that over any two-to-four week period, at least 86 percent of the general population experience one or more common symptoms. Rarely are the symptoms caused by serious illness. “We believe that care must be taken when attributing common symptoms to particular exposures because the association is as likely to be coincidental as to be causal,” the report notes. The full report is available as a PDF on the NIOSH website.
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