With the rising global demand and usage of fossil fuels, the concentration of greenhouse gases such as carbon dioxide in the atmosphere has been increasing at an alarming rate. Monitoring of indoor air quality has now become a necessity in maintaining healthy homes and working environments. This endeavor requires accurate and fast-response gas sensors in order to provide on-time and reliable environmental data. The authors report in this study, the carbon dioxide sensing properties of conducting polypyrrole (PPy) films. Free-standing doped conducting polypyrrole films were synthesized and mounted on a fabricated 4x3 sensor array, and were then exposed to environments of varying CO2 concentrations. Seven of the twelve PPy films in the sensor array demonstrated highly strong correlation to CO2 levels, with Pearson’s correlation coefficient values ranging from 0.714 to 0.992. The PPy film sensors showed high sensitivity with fractional changes in resistance ranging from 1.15% to 38.5% per 100ppm increase in CO2 levels. This study shows that PPy films have potential as active materials for highly sensitive and fast-response CO2 sensors.