STELLA-AQ, a DIY handheld air quality instrument created by Paul Mirel and developed with Dr. Nyssa Rain – Outreach and Communications Coordinator for the Terra mission, is an innovative educational tool that combines carbon dioxide (CO2) and particulate matter (PM) monitoring capabilities in a user-friendly device, requiring no soldering and offering a free build guide, open-source code, and a supportive community forum.

Built on the same platform as STELLA-Q, it allows users to interchange sensors and potentially create other instruments showcasing the STELLA platform’s modularity. 

Build Your Own STELLA-AQ


Official AQI is calculated from a 24 hour average of particulate densities, and includes time averages of CO, O3, NO2, and SO2 concentrations which are not measured by the STELLA-AQ. Please see for official calculations.

* Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.