IoT Particulate Monitoring With a Raspberry Pi Pico W

10 Oct 2025 - by Archie Hilton

One of our employees lives near multiple cement manufacturing sites and has been working on a personal project to measure the level of airborne fine particulates (<2.5µm) in his local village.

This simple prototype uses a Raspberry Pi Pico W and a Plantower PMS5003 with a 1100mAh battery backup in case of power loss, allowing for up to 3 days operation without power. It pushes readings for PM1.0, PM2.5 and PM10 particulate sizes to a separate endpoint every 30 seconds over WiFi.

The average PM2.5 concentration over the course of July was 7.66µg/m³, which falls below the Air Quality Standards Regulations 2010 annual average requirement of 20µg/m³. If we assume the remaining months will be similar, this shows an acceptable level of air quality in the village.

Improvements

We identified several easy wins to turn this prototype sensor into a strong IoT solution:

  1. Using a low-power microcontroller such as the ESP32 range from Espressif can reduce idle current into the single-digit microamp range.
  2. Reducing the sample period allows for the sensor to be turned off between readings, saving more power.
  3. Alternate radio technologies in the 2.4GHz band like Zigbee, or offerings in sub-GHz territories like LoRa (with existing protocols such as LoRaWAN), could extend battery life significantly.

We estimate that average current draw could reach as low as 363uA for readings every 10 minutes, giving a battery life of ~3000 hours, just over 4 months.

Potential Applications

With connected power, the device could be deployed a mesh network within residential areas to measure particulates at various points over a wide area. Including temperature and humidity sensing (with minimal battery impact) further enriches the data gathered at these points, allowing for detailed analysis.

LoRaWAN as radio technology can also enable cheap deployment via existing public infrastructure in major cities, opening up the door to real-time particulate monitoring for major metropolitan areas.

This technology isn’t just limited to outdoors; large factories with fine particulate requirements (for both safety and quality reasons) could deploy these sensors in a similar fashion to monitor air filtration performance.