Data Inaccuracies in Texas State Agency Testing for Ambient and Indoor Carbon Dioxide Concentrations 2005-2011
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Purpose: The purpose of this paper is to explore indoor air quality assessment reports conducted by the Texas Department of State Health Services Environmental Hazards Group relative to building ventilation as measured by carbon dioxide (CO2) concentrations. The TDSHS provides indoor air quality testing in public buildings as mandated in the Texas Government Code. Method: Ambient concentrations of CO2 do not vary as widely as concentrations within indoor, occupied buildings. A range of 300-500 parts per million was developed as an acceptable concentration variance for ambient CO2 levels. The ambient levels of CO2 reported by TDSHS from each building were then compared to this range. If the ambient CO2 levels from a specific site were within the range they were considered typical and normal. If the ambient CO2 levels from a specific site were out of range they were considered suspect. Results. Of the 122 sites in the dataset, 31.15 percent were out of acceptable range and considered suspect. Of the data reported in one year of TDSHS site assessments, the percentage of suspect readings was 100 percent. This year was then followed by a year with 92 percent of all data out of range. Conclusion: Based on these results, TDSHS should examine all reported data from the Environmental Hazards Group for suspect CO2 data and implement appropriate actions to determine why atypical and abnormal ambient CO2 levels were reported. Employee training schedules and instrument calibration procedures should be assessed. Steps should be taken by TDSHS to address the issue of inaccurate interagency reports and to mitigate negative consequences. An agency oversight committee should be formed to assure the collection of reliable data or terminate the indoor air quality assessments offered to other agencies and seek third party companies to perform these assessments.