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About
PurpleAir is a community-driven air quality monitoring platform that combines low-cost IoT sensors with a free, publicly accessible real-time map. The platform hosts data from over 35,000 sensors deployed worldwide, measuring PM2.5 particulate matter, temperature, humidity, and barometric pressure. Sensors are designed for simple installation—requiring only a power outlet and Wi-Fi—and automatically publish readings to the PurpleAir network. The interactive map lets anyone visualize air quality in their neighborhood, city, or region at no cost. For professionals and researchers, PurpleAir offers a Data Download Tool and a developer API providing programmatic access to current and historical air quality records going back to 2016, enabling integration into custom applications, dashboards, and research pipelines. The hardware lineup spans from the compact $139 PIXEL—the world's smallest air quality monitor—to the full-featured $299 Zen model for indoor/outdoor use. Sensors are manufactured in the USA and have been evaluated by the U.S. EPA and AQ-SPEC, lending credibility to their accuracy. Use cases span community health advocacy, wildfire smoke tracking, school environmental education, government and municipal air quality networks, and scientific research. PurpleAir is used by individual homeowners, city agencies, academic institutions, and enterprises alike, making it one of the largest citizen science air quality datasets on the planet.
Key Features
- Real-Time Global Air Quality Map: A free, publicly accessible interactive map displaying live PM2.5 AQI readings from 35,000+ sensors worldwide, updated in real time.
- Affordable IoT Sensor Hardware: A range of sensors ($139–$299) that measure PM2.5, temperature, humidity, and pressure, requiring only a power outlet and Wi-Fi to deploy.
- PurpleAir API & Data Portal: A developer API providing programmatic access to real-time and historical air quality data dating back to 2016 for building custom applications and research tools.
- Data Download Tool: Bulk download historical sensor data for offline analysis, research, or integration into third-party analytics platforms.
- Fire & Smoke Map Integration: A dedicated fire and smoke map combining PurpleAir sensor data with AirNow, NOAA, and National Interagency Fire Center data for real-time wildfire air quality tracking.
Use Cases
- Homeowners monitoring indoor and outdoor air quality to assess the effectiveness of air purifiers during wildfire smoke events.
- Schools and educational institutions installing sensors to teach students about air pollution and environmental science in real time.
- Municipal governments and regional agencies deploying sensor networks to supplement official monitoring infrastructure at lower cost.
- Researchers and academics downloading historical PurpleAir data to study air quality trends, pollution sources, and health outcomes.
- Developers building custom air quality dashboards, mobile apps, or alert systems using the PurpleAir API.
Pros
- Free Public Map Access: Anyone can view real-time air quality data from the global sensor network at no cost, democratizing access to hyper-local environmental data.
- Large, Long-Running Dataset: With over 35,000 sensors and records going back to 2016, PurpleAir offers one of the most extensive community air quality datasets available.
- EPA-Evaluated Accuracy: Sensors have been independently evaluated by the U.S. EPA and AQ-SPEC, providing confidence in data quality relative to cost.
- Developer-Friendly API: A well-documented API enables developers and researchers to integrate real-time and historical air quality data into custom applications and dashboards.
Cons
- Hardware Purchase Required for Data Contribution: To add local data to the network, users must purchase a physical sensor ($139–$299), which may be a barrier for some individuals or organizations.
- Sensor Placement Variability: As a citizen science network, sensor placement and calibration quality can vary, potentially affecting data reliability in some locations.
- Limited Pollutant Coverage: Sensors primarily measure PM2.5 particulate matter; gases such as NO2, O3, and CO are not measured by standard PurpleAir hardware.
Frequently Asked Questions
Is it free to view air quality data on the PurpleAir map?
Yes, the real-time public map is completely free to access. You only need to purchase a sensor if you want to contribute your own local data to the network.
How do I set up a PurpleAir sensor?
PurpleAir sensors require only a power outlet and a Wi-Fi connection. After plugging in the sensor, you register it on the PurpleAir platform and it begins publishing data to the public map automatically.
How can developers access PurpleAir data?
PurpleAir offers a public API through its Developer Portal, providing access to real-time and historical sensor data. Historical records are available from as far back as 2016.
How accurate are PurpleAir sensors compared to regulatory monitors?
PurpleAir sensors have been evaluated by the U.S. EPA and AQ-SPEC and perform well relative to their cost. They are designed to complement—not replace—regulatory-grade monitors, though correction factors are available to improve accuracy.
What pollutants do PurpleAir sensors measure?
Standard PurpleAir sensors measure PM1.0, PM2.5, and PM10 particulate matter, along with temperature, humidity, and barometric pressure. They do not measure gaseous pollutants like ozone or nitrogen dioxide.
