Low-cost air quality monitoring system design and comparative analysis with a conventional method

This paper deals with the development of a portable electronic device that simultaneously measures toxic gases and suspended particles in real time. It is based on a microcontroller board and low-cost sensors including dust sensor, smoke sensor, liquefied petroleum gas sensor, carbon dioxide (CO2) sensor, carbon monoxide (CO) sensor, temperature, and humidity sensors. The proposed electronic device presents several advantages, namely low energy consumption, low-cost equipment, easily deployable in the field, real-time, and large number measurements of parameters (in situ). It can also send automatically alert information and transmit emergency calls to the supervisor if the concentration of measured pollutant (particulate matter PM2.5) is beyond the threshold WHO limit of 25 µg/m3. The proposed electronic device can also be used as an outdoor or indoor air quality monitoring system. Compared to WHO limits, all the values of the parameters measured are generally acceptable, except CO value which slightly exceeds the average threshold value allowed in workplaces. A comparative analysis of particulate matter concentrations obtained from the proposed prototype and a conventional method based on the GENT Stacked Filter Unit Sampler (reference method) is carried out by placing both devices on the same fixed sampling site and collecting data at the same time over a period of two months. A statistical analysis based on linear regression highlighted a good agreement between these two methods with R2 = 0.8897. Furthermore, a reliability coefficient of 1.008 ± 0.01 confirms the effectiveness of the proposed device.