Environmental pollution is one of the most relevant and frequently discussed problems of modern times, given its great impact on life on Earth. Therefore, air quality monitoring is a key aspect in reducing the prevalece of air-associated health diseases. Today, air quality is a fundamental topic in which it has become extremely important to invest. This issue has been accompanied by descriptions of indoor and outdoor monitoring systems, together with critical reviews describing the problems in terms of industrial pollution and their link to human health. This special issue also welcomed papers concerning the effect of air pollutants on patient health, especially during the COVID-19 pandemic outbreak.