A Portable and Power-Efficient Flue Gas Monitoring System for Real-Time Air Quality Measurement

In recent years, real-time monitoring of pollutants in flue gas emissions from industrial and transportation sectors has gained significant attention due to rising environmental concerns and the implementation of pollutant capture technologies. Despite these advancements, existing systems often fail to accurately measure pollutant concentrations in high-temperature flue gases with sufficient temporal resolution. To overcome these limitations, we present a compact and power-efficient flue gas monitoring system capable of simultaneously tracking 15 vital air quality parameters, including CO₂, O₂, particulate matter (PM1.0, PM2.5, PM4.0, and PM10), temperature, humidity, volatile organic compound (VOC) index, CH₄, CO, NO, NO₂, SO₂, and H₂S, with reliable spatial and temporal resolutions. Central to the system is a modular precooling unit, which reduces flue gas temperatures from approximately $150~^{\circ } $ C to within $30~^{\circ } $ C– $45~^{\circ } $ C, enabling sensors to function optimally under thermal stress. To validate the robustness and discrimination capability of the system, field experiments were conducted by monitoring emissions from coal and torrefied biomass combustion in an industrial-scale boiler. The results demonstrate that average CO₂ emission from coal combustion reaches approximately 618 ppm, which is $1.43\times $ higher than those observed from biomass. Additionally, the power analysis of the system reveals an average current consumption of 0.0385 A, which can support the continuous operation for nearly six days using a 5000-mAh battery. The proposed system offers a scalable, cost-effective alternative to bulky commercial analyzers, with strong potential for deployment in industrial emission monitoring, environmental sensing, and smart infrastructure applications.