The intergalactic medium near a quasar must be strongly ionized by the
quasar's radiation. These hot gas bubbles are likely to be
overpressured, and to expand into their surrounding intergalactic
medium. Thus both thermal and kinematic Sunyaev-Zel'dovich effects may
arise near
quasars, and we might expect a contribution from quasars in the
spectrum of fluctuations in the CMBR
(Aghanim et al.
1996).
Aghanim et al. find that the kinematic effect dominates, and
can cause local changes of 
300 µK in the brightness
temperature of the CMBR on scales up to 1 deg. Whether such
structures are indeed present in the CMBR will be tested by the next
generation of CMBR surveys.
Sunyaev-Zel'dovich effects may also be seen from the Lyman 
absorption
clouds seen in quasar spectra
(Loeb 1996).
The
expected effects are much smaller, typically only a few µK and
with angular sizes of less than an arcminute, from the varying numbers
of Ly systems on different
lines of sight. Here again the
dominant contribution to the signal is from the kinematic
Sunyaev-Zel'dovich effect,
and relies on large velocities acquired by the Ly absorbing clouds as large-scale
structure forms.
Either of these effects, or possibly a Sunyaev-Zel'dovich effect from a quasar-related cluster with a deficiency of bright galaxies, or a kinematic effect from colliding QSO winds (Natarajan & Sigurdsson 1997), might explain the observations of CMBR anisotropies towards the quasars PHL 957 (Andernach et al. 1986) and PC 1643+4631 (Jones et al. 1997). However, the reality of these detections remains in some dispute until they are independently confirmed.