AirGradient Open-Source Air Quality Monitors

AirGradient Co. Ltd. was founded in 2019 by Achim Haug and is based in Chiang Mai, Thailand. It started as a volunteer project to measure classroom air in Northern Thailand during the burning season and now builds affordable, open-source air quality monitors for schools, buildings, cities and researchers.

The range covers the AirGradient ONE indoor monitor, the Open Air and Open Air Max outdoor monitors and the new AirGradient Go portable monitor, using sensors for PM2.5, CO2, TVOC/NOx, temperature and humidity. Every monitor comes with a subscription-free dashboard offering alerts, reports, fleet management, calibration tools and full API export. Hardware designs are published under a Creative Commons license. Users include UNICEF, UNDP, the World Bank and universities such as Stanford and Imperial College London.

• Indoor monitor: AirGradient ONE tracks PM2.5, CO2, TVOC/NOx, temperature and humidity.
• Outdoor monitors: Open Air and Open Air Max for community and city networks.
• Portable monitor: AirGradient Go adds GPS, an e-ink display and on-device storage.
• Free dashboard: alerts, daily and weekly reports and historical data at 5-minute intervals.
• Enterprise tools: fleet management, SMS and webhook alerts and branded reports.
• Open data access: full API plus CSV and JSON export, with Home Assistant integration.

International and private schools in Hanoi can monitor CO2 and PM2.5 in classrooms to adjust ventilation. Industrial park operators can deploy outdoor monitors along their boundaries to share air data with nearby residents. Universities can use the open hardware for environmental research and STEM teaching.

No subscription fees for the dashboard or data access lowers the total cost of a sensor network. Each pre-built monitor ships with a test report comparing it against a Palas Fidas reference instrument. Open hardware and firmware avoid vendor lock-in, and the company reports more than 16,000 monitors sold in 2025 with customers in over 100 countries.

Seasonal haze and fine dust are recurring problems across mainland Southeast Asia, pushing schools, employers and city governments to measure PM2.5 locally instead of relying on a few reference stations. Low-cost, calibrated sensors and open data are making dense monitoring networks affordable for the public and private sectors.

AirGradient was founded in 2019 by Achim Haug (CEO) with co-founder Dominik Schraner (CTO) and is registered in Chiang Mai, Thailand. It runs partner and reseller programmes, works with more than 25 research partners, ran a nationwide school project in Lao PDR with UNICEF and is a 1% for the Planet member.