Air & water quality monitoring · PurpleAir, Inc.
PurpleAir
Low-cost outdoor and indoor air quality sensors whose PM2.5 readings feed a free public real-time map.
PurpleAir sells laser-particle-counter sensors that measure PM1, PM2.5 and PM10 alongside temperature and humidity, for indoor and outdoor use. Every registered sensor streams to the free public PurpleAir map, which is widely embedded by news outlets, fire agencies and air-quality apps (including government platforms like AirNow) alongside official regulatory monitors. Because PurpleAir units use low-cost optical sensors rather than reference-grade instruments, raw readings run high during smoke and humidity events; the US EPA publishes a correction formula that PurpleAir and downstream services apply to align consumer readings with regulatory monitors. Data is accessible through a free API for developers and researchers. Revenue comes from one-time hardware sales rather than a data subscription.
At a glance
| Vendor | PurpleAir, Inc. |
|---|---|
| Pricing model | Free tier + paid plans |
| Free tier | Yes |
| Deployment | Cloud |
| Open source | No |
| Best for | Communities, schools and individuals wanting an affordable, real-time local air quality readout, with awareness that readings need calibration against regulatory monitors. |
Pricing
Sensor map and API access are free; revenue comes from one-time hardware purchases rather than subscriptions.
Pricing has not been verified yet — see the vendor's site.
Features
- Outdoor and indoor PM sensors
- Free real-time public sensor map
- Public API for sensor data
- Temperature and humidity readings
- EPA PM2.5 correction factor support
- Wi-Fi connected, cloud-uploaded readings
- Wide embedding in fire and air-quality apps
Integrations
Profile last reviewed September 21, 2026