The three levels of sparks that fell:
There are three levels of Divine sparks that fell into the Kelipos. The first level is the sparks of Kedusha that fell from Tohu as a result of the breakage of the vessels. There were a total of 288 general sparks that fell from Tohu. The second level is the sparks that fell into the Kelipos as a result of the sin of Adam and Chava, when they ate from the tree of knowledge. The third level is the sparks that fall as a result of sin, such as spilling of seed and the like.
 Siddur Im Dach p. 57b