Question of cell phone interference

We have a customer with a large commercial kitchen operation where Sensor Check equipment for automated refrigeration temperature monitoring is installed. This include 30 BLE-enabled sensors and 4 Boron-based collectors. They are concerned that this equipment has made cellular reception for their personal cellphones worse than it was without the equipment. We are using the recommended Particle antennas with the Borons for BLE and Cellular, and the BLE sensors use an antenna on their PCB.

I have suggested turning all equipment off and comparing, but complicating all of this is their close proximity to a major airport which presents its own cellular interference challenges. Any suggestions regarding how to sort this out?

Assuming the BLE sensors are not defective, there should be no issue. BLE runs in the 2400 MHz unlicensed band, and is very low power. Wi-Fi (2.4 GHz) also uses this band. Cell phones do not use the 2400 MHz because it's crowded with BLE and Wi-Fi traffic.