Impact of airflow and N/P ratio on CO2 removal by chlorella vulgaris: A study with real-time monitoring using low-cost sensors

Climate change represents one of the greatest challenges we face globally, and reducing carbon dioxide (CO 2 ) emissions is among the most urgent actions. In this study, we explored an alternative approach using microalgae ( Chlorella vulgaris ) to capture CO 2 from the air, employing an Arduino-controlled biofiltration system with accessible sensors such as the MQ-135 and TESTO 535. We tested different airflow rates (50, 75, and 100 liters per hour) and nutrient combinations (N/P ratios of 0, 108.33, and 216.67) to identify the most efficient conditions. Unlike other studies, we integrated real-time monitoring of variables such as CO 2 concentration, temperature, and light within a modular, easily adaptable system. The best results were achieved with a flow rate of 100 L/h and an N/P ratio of 216.67, yielding a capture efficiency of 34.88% and a daily productivity of nearly to 1 g/L. This proposal demonstrates that it is possible to develop effective, economical, and replicable solutions that combine accessible technology and biotechnology to help mitigate climate change. • Air biofilters to reduce CO 2 concentration can be monitored with Arduino sensors and microcontrollers. • High concentrations of N and P, even in ratios where P exceeds N, allow CO 2 concentration to be reduced at high air flows. • Chlorella vulgaris is able to remove CO 2 from the air up to 34.88%.