This is a tough question to give a general answer to. Broadband interference from sources like motors will affect your link budget, though if the motor manufacturer is following the law, it should not cause much interference, as they have to be filtered to pass FCC Part 15, which governs such unintentional radiated emissions.
Cell towers are generally good neighbors, so no worries there, unless your gateway is close to the near field of something like a high power television transmitter.
All that said, it's best to do tests early in your project to see how interference affects your link. We've installed telematic systems in heavy industrial factories, and there is interference. Generally that means more repeaters. We also created a field survey tool to help ensure network coverage is adequate.