Help! - Gravity: Analog Infrared CO2 Sensor For Arduino SKU: SEN0219

Graph shows measured concentration of carbon dioxide from the sensor. X-axis is data points, where data was taken once every 5 seconds (Domain: 0 to ~10 hours).
This is data taken overnight from the Gravity: Analog Infrared CO2 Sensor For Arduino SKU: SEN0219. The sensor was exposed to the outside air for nearly 10 hours, and we expected it to show change over time, which it did not. Please help!

Other notes:

The sensor does respond to us exhaling on the sensor, but did not respond to well-executed lab testing with changes of approximately +150 and -500 ppm.

The data only appears to read 7 or so values randomly with windows of about 20 ppm in between (However, when exhaling on the sensor, the resolution appears to be better which makes no sense to us). We only expect to read values under 500 ppm for our experiment, so is there any way to improve the resolution/sensitivity of this sensor for the lower range(0~500ppm)?