Abstract
We present chemical evolution models for the dwarf irregular galaxy NGC 6822, using as observational constraints chemical abundances of planetary nebulae (PNe) and HII regions derived from both, collisionally excited lines (CELs) and recombination lines (RLs) methods. We built two models that reproduce gaseous mass and the O/H derived for those two methods in order to discriminate between abundances obtained by CELs and by RLs. Both models produce a fair agreement with observations, but the predicted Δ Y/Δ Z value for the RLs model is in better agreement with those values observed in Irr galaxies.
