In spite of the advent of medical technology, modern newborn incubators (NIs) do not protect them from high noise levels in the neonatal intensive care units (NICUs). Allied to bibliographical research carried out measurements were made inside the dome of a NIs and the results show that the sound pressure levels, or noises, are much more intense than the levels stipulated by the norm NBR IEC 60.601.2.19 of ABNT. These measurements revealed that the NIs air convection system motor is the main source of excess noise. In view of the above, a project was developed with the objective of significantly reducing the noise level inside the dome by modifying the air convection system. Thus, a quantitative study was developed, based on the experimental method, where a ventilation mechanism was designed, constructed and tested, which operated from the network of medical compressed air, present in the NITUs and maternity rooms. Respectively, before and after the modification of the air convection system, the data of relative humidity, air velocity, atmospheric pressure, air temperature and noise [(64.9 % ur / 33.1 % ur); (0.27 m/s / 0.28 m/s); (1.013.98 hPa / 1.013, 60 hPa); (36.5 ºC / 36.3 ºC); (45.9 dBA / 30.2 dBA], were collected by electronic meters that registered the conditions of the external and internal environment of the dome of an NI with a passive humidification system. The noise measurements in the environment showed that there was a strong reduction of 15.7 dBA, or 34.2% of internal noise, measured after the modification of the ventilation system, showing a significative performance of the modified NI. Therefore, our results may be a good choose to improve NI acoustics to enable optimal care of the neonate in the neonatal intensive care units.