I think this is more a chemistry stack exchange question but I believe being related to a computer it isn't well received there.
Canned air spray is used to clean dusty internal or external components. Sometimes it has vapor or liquid that comes out in pressure.
I wonder if it is able to trigger Liquid Submersion Indicator (LSI) or Liquid Contact Indicator (LCI) present on MacBooks motherboard.
This indicators turn red when in contact with (water?)
Wiki always refer to water so i'm not sure.
Apple recommends using canned air spray for some macbook keyboards but i guess the layers of keyboard are more resistant to liquid contact.