Our Technology

Based on a new generation of low-cost laser particle detectors, PurpleAir sensors use WiFi to communicate and upload data to the cloud from where it is shared on the PurpleAir map.

Laser Particle Counter:
PurpleAir uses PMS6003, PMS5003, and PMS1003 laser particle counters. These sensors count suspended particles in sizes of 0.3, 0.5, 1.0, 2.5, 5.0, and 10um. These particle counts are processed by the sensor using a complex algorithm to calculate the PM1.0, PM2.5, and PM10 mass concentration in ug/m3. PMS sensors come factory calibrated.

Before deploying any devices, we verify that they are giving out readings that are consistent from sensor to sensor during tests in a smoke chamber.

ESP8266 and Arduino air quality sensor:
PurpleAir sensors use an ESP8266 chip to talk to the particle counter and provide all functionality, including connecting to a WiFi network and uploading data to the cloud. PurpleAir firmware has remote update features, meaning we can modify the software and the sensor will download the new version and update itself. Each PurpleAir air quality sensor device checks for updates from time to time.

ThingSpeak and HighCharts:
ThingSpeak provides the cloud storage for PurpleAir sensor data. PurpleAir uses HighCharts and data stored on ThingSpeak to create graphs on the PurpleAir map.

Using services from Google makes for a robust, reliable, and secure system. Google App Engine provides the hosting for the PurpleAir map.

PurpleAir is currently migrating to BigQuery for data storage and historic data will be served from the PurpleAir API (api.purpleair.com)

Mapbox provides the PurpleAir map interface.

BME280 Sensor:
Each PurpleAir sensor includes a BME280 pressure, temperature, and humidity sensor. Our FLEX sensor now also incorporates BME680 or BME688 which include a gas sensor.

Please note: Temperature values may be elevated due to the heat generated by the WiFi module, sun, and other possible influences. These values are provided as-is and are meant to give an indication of the operating conditions for the PurpleAir device. Generalized correction factors are applied to temperature and humidity data presented on the map, but this correction will not cover all circumstances.

Power Supply:
PurpleAir sensors are powered by a 5v USB power source. Read about the power supply that PurpleAir offers here.

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