Air quality measurement is essential for decision-making and the establishment of public policies that promote health, well-being, and sustainability. This work proposes an autonomous air quality monitoring system powered by photovoltaic energy, aiming to contribute to the expansion of sustainable environmental monitoring networks. The developed system incorporates energy harvesting elements, using solar panels and power management integrated circuits (PMICs) to ensure energy autonomy and portability. A prototype was built to monitor carbon monoxide (CO) and transmit measured data through Wi-Fi. This prototype kept continuous operation for four days having only solar power and batteries as energy sources. These results highlight the feasibility of using photovoltaic energy in low-power systems, especially in remote or hard-to-access locations, reinforcing the importance of sustainable technologies for air quality monitoring. A methodology to design air quality measurement projects was also developed, enabling the replication of the system in different contexts.