Mayan ruins are suffering degradation due to high relative humidity, high temperatures and natural and anthropogenic pollution. Archaeological sites and historical monuments in the mayan area were constructed of different calcareous limestone, which offers different degradation resistance to increasing contamination. In this study a characterization of two calcareous limestone were carried out, when they are exposed to natural and accelerated weathering. It was demonstrated that a calcareous white3 limestone type losses weight in an average amount of 5.75 kg/m 51 ’ , while a red one losses 6.17 kg/m , after a year of exposition in a rural atmosphere. Keywords: Mayan area, archaeological monuments, calcareous limestone, degradation, sulfur and dioxide pollution