Countless problems have been caused by the excessive emission of polluting gases, such as carbon dioxide (CO₂), into the atmosphere. Therefore, more effective monitoring of CO₂ is essential, especially in central or industrial regions. Thus, this work shows the development of a platform for monitoring the CO₂ concentration, which is composed of autonomous and independent sensors that have their own energy source, storage capacity, and data replication for the central server. To validate the platform, CO₂ measurements were taken at three strategic points in an outdoor environment in a Brazilian urban center. This platform proved to be an evolution over another system previously proposed by the group that was based on the use of a wireless network of sensors to monitor CO₂. This new project managed to overcome limitations that compromised the efficiency of the first platform, which were mainly related to the interference in the communication signals between the network sensors due to the existence of physical barriers in the monitoring environment. With that, this new platform showed greater security in the maintenance of collected data and allowed for the expansion of the physical complexity of the environments that can be monitored.