We conducted an Indoor Environmental Assessment of an office building that had several employee complaints with increased allergies and unusual odors while in the building.
The office had a previous roof leak which caused the initial concern. The real issue was with the negative pressure of the office space and the positive pressure of the warehouse that it's located in. Originally sized for just under 2000 sq ft the office is now over 2400 sq ft.
The office is in a warehouse that has a ceiling height of 20 ft and the office has a suspended ceiling of 9 ft. The 2 doors that lead to the warehouse space have no threshold or weather stripping and there are large areas with no insulation over the office space suspended ceiling.
The warehouse has a large over head door that when opened with the wind blowing the positively pressured warehouse is forcing a large amount of respirable particulate into the office through the suspended ceiling.
The fix... properly seal and insulate the office. Properly size and duct the HVAC for the new office space and create a positively pressured office. Keep what's in the warehouse in the warehouse.