Blowing regular air in or sucking it out, with or without dust and other particles puts your system at high risk of static electricity. The dryer the dust, and lower the humidity, the greater the risk. Vacuum cleaners are by far the most dangerous, but hair dryers, and any other device that moves a volume of air and dust or other particles. Canned air using one of the five top gasses such as difluoroethane gas or others dramatically limits static discharge. Risk is increased the faster the air and particles move.
You may think your system is safe because you have been doing it for weeks or years. You may someday be surprised. Static electricity can destroy a hard drive, any chip on the motherboard, CD-Rom, any PCI, AVG, or PCI-Express card, memory, flash drive, floppy disc, power supply.
You can prove this by running your own tests. There are various films that will record the streaks, and many other devices.
We have been in the repair business since 1986. We have seen what seems like every possible combination of damage from static electricity.
You will be shocked by what you learn... Shocked I tell you!