[O III] line ratios and evolution of oxygen abundance with redshift

Understanding chemical evolution of galaxies has been revised by the James Webb Space Telescope up to early universe at high-redshift (high-z). Using new atomic data, we analyze reportedly observed [OIII], [OII], and [SII] line ratios from 44 local to high-z galaxies to derive electron temperatures and densities. Based on nebular temperature-abundance relations we may track the evolution of [12 + log(O/H)] with redshift. Our [O III] collisional-radiative-recombination model incorporates possible (e + O IV) --> O III recombination-cascade contributions to forbidden lines using new level-specific recombination rate coefficients and transition probabilities, with earlier collision strengths data. We find that individual galaxies show a large and systematic variation with electron temperature in the nebular range 5000-25,000K, and O-abundance down to 6.75 compared to the solar value 8.70. The O-abundances vs. redshift display a broadly decreasing trend toward high-z ~ 10, with a best fit ranging from 8.25 to 7.50 from the present epoch at z = 0, generally consistent with previous works on O-abundance-redshift variation. We also explored AI Machine Learning models to predict and complement directly derived results, with preliminary simulations trained on observed flux ratios and PyNeb-simulated datasets that are promising but limited by current sample sizes. Future work may expand datasets and refine statistical models to establish robust constraints on early-universe chemical evolution.