Environmental monitoring systems allow the evaluation of variables such as CO2, CO, volatile organic compounds, temperature, and humidity as they help maintain surveillance of closed places, providing safe and comfortable indoor environments. Several devices perform environmental monitoring for specific chemical or physical variables. In particular cases, some prototypes also opt for full monitoring models where chemical, physical, and/or geographical variables are gathered, integrating them into a single system. The main challenge is acquiring and processing signals in real-time and with different sampling frequencies. In this paper, a performance analysis is presented in prototypes of multivariable monitoring systems with different sampling times acquired with an ESP32 microcontroller, where in one case, sequential programming is proposed, widely used in monitoring systems, and a second alternative where programming is optimized that incorporates multitasking and multi-core capabilities. The results show an improvement of up to 28.5% in a monitoring system of nine different physical and chemical variables.