how to blur pf source particles.

Hello all max Guru`s.i have created particles falling down like water foam 
falling of a wave using pf source.The problem is i want to give a image blur 
to the particles.I can give a image blur to all other particles but cant to 
pf source.As it should look like water foam and the particles were not 
enough so i tried after burn as it was done in the Intermedia case study.But i 
cant even figure out how to blur afterburn particles.

Plz help????????

Regards,
Raj D Sakpal

(volcano picturz)