Low-cost sensor system can check indoor air quality in real time

Humans spend about 80% of their time indoors, but keeping track of the air we breathe usually requires expensive lab-grade equipment. Researchers at Concordia and Qatar University have created a low-cost sensor system that does the job just as well—and in real time.

The devices are built on Arduino microcontrollers—tiny, affordable computers often used in research and do-it-yourself projects. Hooked up to sensors, they measure carbon dioxide, fine particles and nitrogen dioxide. They also track volatile organic compounds (VOCs) like benzene, formaldehyde and acetone—gases that can be released from paint, cleaning products or car exhaust.

Data is sent wirelessly to an online dashboard, where users can view live charts and air quality indexes. The technology is detailed in an article published in the journal Atmosphere.

To prove the system’s reliability, the team tested it in two very different climates: Montreal’s cold, humid winters and Doha’s hot, dusty desert air. Many low-cost monitors struggle when conditions shift, but this system stayed accurate within 15% of commercial instruments in both environments. It also responded quickly to real-world changes, like cooking smoke or rush-hour traffic.

By making indoor air monitoring both affordable and climate-resilient, the project could help schools, workplaces and public spaces worldwide spot problems faster and keep people healthier.