2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/10443We discuss the photoionization of the intergalactic medium by early formed quasars and propose a mechanism which could generate measurable temperature fluctuations $δ_{T }~=~ΔT/T$ of the cosmic microwave background (CMB). Early quasars produce individual ionized regions around themselves. We evaluate both thermal and kinetic (first-order Doppler) Sunyaev-Zeldovich (SZ) effects associated with those ionized regions.11 pages, 9 postscript figures, using l-aa.sty (included), gziped tar tex files; accepted (1995) in Astron.AstrophysAstrophysicstext