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Indoor Air Quality

We wanted to share information about Indoor air quality because it is such a challenge. 

It’s a challenge because-

On the one hand, it is serious.  Poor quality or contaminated air quality can affect employee productivity and health.  Plus, most complaints are difficult to distinguish from common flu or cold symptoms.

On the other hand, the most common cause of complaints is often a simple lack of maintenance on the building’s air handling system.  A simple, inexpensive fix. 

Our message, then, is don’t let the potential difficulty in determination keep you from finding out if you have a problem.

Pay Attention

Employee complaints caused by poor indoor air quality can be non-specific and sometimes similar to those caused by colds, flu, stress and allergies.  It can initially be difficult to determine if problems are caused by sources or conditions in the building, and what can be done to remedy the complaints.


Every response should start with an inspection of the air handler unit(s) servicing the area of complaint.  Sometimes, pre- and inner-filters of the building’s heating, ventilation and air-conditioning (HVAC) system have exceeded their useful life.  Putting HVAC maintenance and inspection on a firm schedule is an easy and inexpensive fix.  The HVAC inspection can be performed either by Ellis or (even better) by the building’s professional maintenance staff.

If testing is needed, proper initial testing is also an easy and inexpensive starting point.  This will often include placing a “Q-Trak” monitor in the area of complaint. A Q-trak measures and records concentrations and trends in carbon monoxide, carbon dioxide (CO2), temperature and relative humidity.  CO2 concentrations of 1,000 ppm or more produce complaints of stuffy air, itchy eyes, etc.  As with most indoor air quality issues, elevated CO2 levels are most often traced to problems with the building's HVAC system.

Many times the investigator must consider all the factors that relate to indoor air quality to identify possible contaminants and stressors which could be responsible for the reported complaints and effects. This requires a process of identifying and eliminating numerous potential contaminants, sources and other factors in the hope that the true causal factor will eventually be identified. It requires time and patience on the part of both the building owner and it occupants.

In any case, indoor air quality is a serious issue, and depending on the results of its initial investigation, Ellis may also recommend and perform testing for the following contaminants:

  1.   airborne mold
  2.   surface mold
  3.   allergens
  4.   ultrafine dust particles emitted from printers and copiers
  5.   respirable and nuisance dust, usually from nearby construction activities
  6.   hydrogen sulfide (sewer smell)
  7.   fecal contamination (E. coli & Enterococcus), most often performed following a sewage leak and cleanup
  8.   airborne asbestos
  9.   bulk asbestos
  10.   airborne lead
  11.   damaged lead paint
  12.   volatile organic compounds (VOCs), emitted from chemical processes - SUMMA-type canister or TEDLAR bags
  13.   formaldehyde, a contaminant associated with urethane insulation, preservatives and embalming processes
  14.   propane
  15.   legionella
  16.   other contaminants, depending on site specific needs


Depending on the targeted contaminant, Ellis will partner with CalScience Laboratories, EMSL, LA Testing, Silliker Labs, and other local and national AIHA- and NVLAP-accredited laboratories. 

So, to summarize:

If you suspect something, have the building’s HVAC system checked.  If nothing changes, start initial testing.  Better to confirm there isn’t a problem than let one go too long, putting a potential drag on productivity at the very least, and possibly putting your employees’ health at risk.