Minecraft wiki entry for Development_versions, associated text: New ParticleParam1 and ParticleParam2 integer tags for area effect cloud entities.
These work just like the two <params> arguments work, in /particle.
Example: /summon AreaEffectCloud ~ ~1 ~ {Duration:600,Radius:2.0f,Particle:"iconcrack",ParticleParam1:351,ParticleParam2:3}.
Summons a cloud of iconcrack particles with the texture of item 351 (dye), and data value 3 (cocoa beans).
Example: /summon AreaEffectCloud ~ ~1 ~ {Duration:600,Radius:2.0f,Particle:"blockcrack",ParticleParam1:12289}.
Summons a cloud of blockcrack particles with the texture of block 1 (stone), and data value 3 (diorite), using the formula 1+(3×4096).