School Health Complaints Not Due to Mold

 

Testing was done in one of our elementary schools due to staff complaints about headaches, fatigue, and other symptoms.  The testing was also prompted by water infiltration due to roof leaks.  The highest level of Aspergillus/Penicillium in one classroom was 252 (count per cubic meter).  Other molds at lower concentrations were:  Alternaria (21), Ascospores (84), Basidiospores (42), Cladiosporium (42), Epicoccum (21), Myxomycetes (42), Pestalotia (21) and Pithomyces (42).  Outdoor testing did not indicate the presence of any of these mold spore types.  Testing was done in the winter in northern Massachusetts.  Should we have any concerns for the health of students and staff?-Brian , New Hampshire                                                          

           

            These test results do not indicate that a mold exposure problem exists in your school spaces where samples were collected.  In addition to the fact that counts being relatively low, most spores identified are characteristically from outdoor mold genera.  One can fairly ask why should there be outdoor mold present indoors when the outdoor sample did not have any of these mold genera present? That actually is easy to explain.  Outdoor mold types under winter time conditions are fewer in number and different from those observed in other seasons.  The indoor samples were likely collecting mold spores that entered the building in the past (most likely during the fall months).  Such spores can go through many cycles of settling out and being re-suspended (months or more).

            One of the problems that has occurred with building owners and occupants’ focus on mold in the past decade has been the fact that every indoor air quality health concern has become for all practical purposes a mold concern or issue.  Unfortunately, this has meant that other long-standing and even more likely causes of indoor air quality/health complaints have been ignored.

            In school buildings occupant complaints of headaches and fatigue are highly unlikely to be associated with mold exposures that primarily cause allergy-type respiratory symptoms.  Rather such symptoms are characteristic of poor ventilation conditions.

            Studies that we have conducted as well as studies on school buildings/classrooms in Texas indicate that approximately 50% of public school classroom spaces are slightly-to-very poorly ventilated based on measurements of carbon dioxide (CO₂), an indicator of ventilation adequacy.

            My historical experience in conducting problem building investigations (most notably in school buildings) is that complaints of headache and fatigue are indicator symptoms of poor quality air associated with inadequate outside air being provided for ventilation.  The causal agents are not known but are likely to be human bioeffluents, substances that we individually release into building spaces.  Carbon dioxide is the most abundant and easily-measured human bioeffluent and can be used as an indicator of overall bioeffluent levels.

            In my investigations it was typically the case that with increasing CO₂ levels the complaint rates of headache and fatigue increased, with occupants indicating that headaches/fatigue were first noted in the morning hours between 10-11:00 a.m. and resolved within an hour or so after leaving the building.

            On a probability scale it is most likely that staff air quality/health complaints are associated with poor ventilation conditions in the school building and that the water intrusion problem/mold concern distracted individuals involved from identifying the most likely causal factor for complaints.

 

February 13, 2008