Date of Award

Spring 5-1999

Document Type

Master's Research Paper

Degree Name

Master of Science (MS)



First Advisor

Dr. Robert Miller

Second Advisor

Dr. Martin M. Fontenot, Jr.

Third Advisor

Dr. Talmage Bursh


The purpose of this study was to identify and determine the concentrations of targeted inorganic gases and total volatile organic compounds known to exist in indoor air spaces. The Louisiana Department of Environmental Quality (LADEQ) Office Building was selected because of a survey of occupants' symptoms and perceptions of indoor air quality. Collected air samples were analyzed for selected compounds by way of United States Environmental Protection Agency (USEPA) sampling procedures and methods that utilized drager absorption tubes and a gas chromatograph/mass spectrometer. The targeted compounds were nitrogen dioxide, dinitrogen oxide, carbon monoxide, VOCs (volatile organic compounds), formaldehyde, and carbon dioxide. The results of this study indicate poor indoor air quality as a major factor influencing occupants' symptoms. Within the scope of this research, findings indicate that the fresh air exchange rate in the building was too low. Exhaust fans were not working properly in the restrooms on floors three, four, five, and six -- causing the presence of 1,4-dichlorobenzene (a VOC) at concentrations ranging from 1 IO ppm to 125 ppm. Moreover, the high concentrations of carbon dioxide (500 ppm to 1500 ppm) gave additional evidence of an improperly working ventilation system being the cause of occupants' symptoms. On the positive side, data from the present study, when compared to indoor air quality data collected by another investigator in 1997, showed a decreasing trend in the concentration levels of VOCs and carbon dioxide in the office building. After an overhauling of the heating and air conditioning system in the building, the average carbon dioxide concentration in the indoor air samples collected dropped from 1,157 ppm (before overhauling) to 743 ppm (after overhauling). Concentrations of nitrogen dioxide, dinitrogen oxide, and carbon monoxide were found to be below detection limits. Except on the third floor where it was found to be 0.04 ppm, the concentration of formaldehyde was found to be below its detection limit. A concentration of 0.04 ppm, however, is below the dangerous threshold limit of 1 ppm for formaldehyde.