Gillings School alumna investigates why NC teachers have trouble breathing in their classrooms

May 13, 2015

Kim Gaetz, PhD, who earned a doctorate in epidemiology at the Gillings School of Global Public Health in 2014, was featured in a May 7 article in Endeavors, UNC’s research magazine. The article, by Ashita Gona, is reprinted in part below. Read the complete article on Endeavors’ website.

Dr. Kim Gaetz

Dr. Kim Gaetz discovered that it’s not difficult to find classrooms with bad air quality in North Carolina.

She conducted her research with 10 schools in two North Carolina districts. She used hygrometers to find classrooms’ relative humidity, a measure of how much moisture is in the air. Out of the many factors that can contribute to poor air quality, Gaetz chose to measure humidity because of the strong impact it can have on health.

Humidity that is too low can lead to dry eyes and skin. High humidity can encourage dust mite reproduction, mold growth, and can attract rodents and cockroaches, which cause allergies. To find the perfect range, Gaetz used the Environmental Protection Agency’s recommendation that classrooms keep their humidity between 30 and 60 percent.

Keeping humidity within this range can reduce the amount of harmful chemicals, like formaldehyde, in the air. There is even evidence, Gaetz says, that keeping humidity within the ideal range can prevent the spread of infectious diseases, like influenza.

“Surprisingly,” she says, “there were not a lot of classrooms that were able to stay in that range. One school wasn’t able to be in that range at all.”

Between October 2010 and June 2011, Gaetz asked the participating teachers—over 100 of them—for permission to put hygrometers in their breathing zone, or an area of their classroom where they spent most of their time. She also asked the teachers to fill out a survey detailing their health and work history, and she conducted an initial air quality inspection of the classrooms. Along with that, the participants filled out weekly surveys about their health.

Gaetz found that schools had an especially hard time controlling humidity in the winter, when the heating systems created dry indoor air, and in warmer months, when air conditioning units created humid indoor air. Economizers, which are devices that reduce energy consumption and costs, also raised humidity in classrooms.

However, she says, schools that maintained their systems four times per year, as opposed to once, were more likely to stay within the recommended range.

Gaetz says there was an increase in wheezing, tightness of chest, and shortness of breath among any teachers who had especially high or low humidity for at least 5 days in a row. Gaetz calls the symptoms experienced by these teachers “pre-asthmatic,” because they could lead to asthma or be a sign of undiagnosed asthma.

While her sample size was not large enough to say conclusively that humidity out of the ideal range was affecting the health of teachers, Gaetz said the suggestion that it does has made her want to look into doing a larger study.

Gaetz also hopes to expand her research to other influences of bad air quality in classrooms, including carbon dioxide and common chemicals, and would like to pursue research on how humidity can affect the spread of diseases. She says if researching air quality can protect teachers and students, it is worth looking into.

It is important to her, she says, to find ways to give back to the communities where she is conducting her research.

Gaetz is currently an Oak Ridge Institute for Science and Education (ORISE) postdoctoral scholar at the Environmental Protection Agency. She received the UNC Graduate School’s 2015 Impact Award for research that benefits the people of North Carolina.

Read more in Endeavors.