Provided herein are systems for continuously measuring oxygen and carbon dioxide gas levels inside a cell culture incubator, comprising an oxygen sensor that uses LED based fluorescence technology to determine the amount of oxygen in the surrounding atmosphere, a carbon dioxide sensor that uses LED based Non-dispersive Infra-Red (NDIR) technology to determine the amount of carbon dioxide in the surrounding atmosphere, and electronics to wirelessly monitor the output from the oxygen sensor and carbon dioxide sensor. Most preferably, the system can be placed inside a cell culture incubator, and sensor readings are pre-compensated for temperature, pressure, and humidity. Also provided herein are methods of using the same.