The Collaborative International Dictionary of English v.0.48:

Pneumato- \Pneu"ma*to-\ (n[=u]"m[.a]*t[-o]- or
   n[-u]*m[a^]t"[-o]-).
   A combining form from Gr. pney^ma, pney`matos, wind, air,
   breath, respiration; as, pneumatograph, pneumatology.
   [1913 Webster]