From Lifewire:
Todd Richmond, a professor at Pardee RAND Graduate School and an IEEE member, told Lifewire in an email that many toxins and pollutants are invisible to the naked eye, so dedicated sensors are necessary to monitor air quality.
“If you don’t know there is a problem, then you can’t try and solve it,” he added. “Having a robust and ubiquitous air monitoring system is critical for understanding risks, both current and future, and giving the necessary data to explore causes and effects. Think of low-cost air quality sensors as a neighborhood watch for your lungs.”