Hi @Bumchamp7,
More information on channels A and B is found here: What are Channel A and Channel B?.
The laser counters in PurpleAir sensors measure the air quality independently of each other. This means that the readings on one channel may be different from another.
The data from PurpleAir laser counters correlate very well with regulatory monitors. The US EPA created the “US EPA” conversion factor to match PurpleAir sensor data even closer to that of regulatory monitors. Evaluations done on the sensors can be found here: PurpleAir Sensor Evaluations and Studies.