The HVAC industry has used mechanical and electrical sensors to measure temperature, humidity, pressure, and airflow for a very long time. These measurements provide critical inputs to control the systems that maintain the comfort in a building. However, they do not provide the insight needed to understand the quality of the air from a cleanliness or hygienic perspective. To properly evaluate the overall indoor air quality, sensors are needed which measure parameters such as CO2 levels, particulate, presence of VOC contaminants and other factors that impact the quality of the indoor environment.