We have a number of employees in our office who have itchy, watery eyes, nasal congestion, headaches, lethargy and trouble concentrating. Most of the affected folks report they feel better at home and worse after they’ve been in the office for about an hour. We had the office tested for mold but nothing remarkable was found. What’s going on?
While exposure to molds can certainly produce some or all of the symptoms listed above, mold is not the only cause. The complaints could be triggered by an allergic response to pollen from trees, grasses, or indoor potted plants. They could be caused by bird dander that passed through the HVAC system’s filters. There could also be chemical causes. Aside from obvious external sources, such as a nearby smokestack industry, your employees could be responding to carbon monoxide levels resulting from a leak in your gas furnace’s exhaust duct. Or, the symptoms could result from a drop in oxygen levels and a simultaneous build-up of carbon dioxide due to insufficient fresh make-up air.
How can you identify the real cause? Well, you’ve already eliminated one of the most common sources of these symptoms: mold. We can eliminate the common cold or viruses, because your employees feel better outside the office and worse when they come back in again. On-site, real-time measurements of oxygen, carbon monoxide and carbon dioxide levels will quickly reveal if these are the culprits. Collecting samples of the office air and examining for animal dander, fibers, pollens and chemicals will pinpoint any of these agents as the source of complaint.
In the absence of any positive findings, the source of the problems could be an agent that has not hitherto been identified or suspected. It is also possible that the complaints stem from Mass Psychogenic Illness. Our experience in this field, however, suggests that these last two potential causes are rarely encountered.