Description
Open Air Outdoor Air Quality Monitor
The AirGradient Open Air (Model O-1PST) is an outdoor air quality monitor that lets you know if the air you’re breathing is healthy. It measures PM 2.5, CO2, TVOCs, NOX, Temperature and Humidity. It’s fully open-source and customizable, with flexible data platform options and smart-home integrations.
Get this monitor as an easy to assemble kit - A quick & fun assembly project for people who enjoy building simple electronics kits.
Try the AirGradient Dashboard now!
Track, analyze, and visualize air quality across locations; set alerts and get daily/weekly reports. No monitor required for the demo. Launch the demo.
Community and Map
Thousands of open-hardware monitors run in 80+ countries. You can opt-in to share your outdoor data publicly on the AirGradient Map and with OpenAQ, a non-profit democratizing access to air quality data.
Easy to Assemble, Setup & Install
Available fully assembled or as a kit with detailed guides and videos. Connect to Wi-Fi, the dashboard, and the map. Get help directly from AirGradient support or the community forum.
Mounting Options
Mount on walls or poles. For poles, use two stainless steel zip ties through the holders; for walls, use two screws. A small hole allows a secure screw to deter theft. The fully weather-proof enclosure is designed for exposed outdoor installation.
Optimized Enclosure
Engineered for accurate airflow to the sensor modules, avoiding air loops and reducing internal condensation risk. The enclosure uses robust, UV-resistant ASA plastic for long-term durability and UV protection.
Get the AirGradient Open Air
- Model O-1PST
- Measures PM 2.5, CO2, TVOCs, NOX, Temperature & Humidity
- 4 m USB-C to USB-A cable (without power plug)
- 24 months AirGradient data platform with map (or connect to your own server, e.g., Home Assistant)
- Fully open-source firmware/code; local Home Assistant auto-discovery
- Fully assembled & test-chamber verified (with report)
- Certified: CE, FCC, RoHS, REACH
- 12-month warranty
Also available as a kit with the same hardware; due to self-assembly, kit units differ in warranty/certifications.
Technical Data
| Model | O-1PST (AirGradient Open Air) |
| Microcontroller | ESP32-C3-MINI (RISC-V up to 160 MHz; 4 MB flash) |
| Wi-Fi | 2.4 GHz IEEE 802.11 b/g/n |
| Bluetooth | Bluetooth LE 5 / mesh |
| Extensions | Breakouts: I2C, 3×GPIO, 2×UART |
| Peripherals | Status LED, Push Button, USB-C |
| External Watchdog | Texas Instruments TPL5010 |
| Particle Sensor | Plantower PMS5003T (PM1, PM2.5, PM10); PM2.5 accuracy ±10 μg/m³ (0–100) / ±10% (100–500) |
| T/RH Module | ENS210 (inside PMS5003T; ±0.2 °C; ±3.5% RH; dashboard applies ambient correction) |
| CO2 Sensor | SenseAir S8/S88 (NDIR) 0–10,000 ppm; accuracy ±40 ppm ±3% of reading (typical range) |
| TVOC/NOX Module | Sensirion SGP41 (VOC Index; NOX Index) |
| Enclosure | ASA plastic, UV-resistant & weather-proof |
| Mounting | Wall or pole mounting |
| Cable | 4 m USB-C to USB-A (with data lines; 2A 5V USB-A power plug required, not included) |
| Certifications | CE, RoHS, REACH, FCC ID: 2AC7Z-ESPC3MINI |
Download specification sheet (PDF)
Open Hardware, Open Source, Open Data
All code, schematics and 3D files are open-source (CC-BY-SA 4.0). You own your data — AirGradient’s philosophy rejects monetizing user data; the data your monitor generates belongs to you.
Ideally Combined with Indoor Monitors
Pairing indoor and outdoor monitors reveals sources, ventilation effectiveness, and helps compare environments in combined dashboard reports. See the indoor monitor page.
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Additional Resources