How do the PM2.5 sensor and CO2 sensor work?

1. How does the PM2.5 laser sensor work?

The AirVisual Node/Pro uses a light scattering laser sensor for PM2.5 measurements. How it works is that within the sensor's measuring 'chamber', a laser light beam is shone onto particles, and this light is then irradiated in all directions from these particles (scattering). A light detector (or 'photometer detector') then measures all of this scattered light, and from this, the sensor can calculate the concentration of particles within the chamber. In this way, the sensor is able to detect near microscopic particles ranging from 1μm to 10μm. The sensor in the AirVisual Node/Pro also has a small fan to ensure a constant flow of air through the measuring chamber.

Each reading reported from the sensor is calibrated by a special algorithm which takes into account external temperature and humidity values.

2. How does the IR CO2 sensor work?

The CO2 censor is composed of an infrared (IR) lamp, a reflective gas cell, and IR filtered detectors. The IR lamp sends waves of light towards the IR filtered detectors, which can measure how much IR light reach them. While the IR light goes through the cell, CO2 modules absorb lights of certain wavelength (shown in the graph). Thus, the number of CO2 modules in the cell can be calculated by comparing the amount of light IR lamp radiated and the amount of light detectors received.

The AirVisual Pro/Node

  1. How can I make my outdoor Node/Pro's data public?
  2. Chinese users: AirVisual Node/Pro常见问题
  3. AirVisual Node/Pro software updates - Changelog
  4. Download the AirVisual Node/Pro's data using Samba
  5. How to access the AirVisual Node/Pro's API
  6. How to connect the Node/Pro to Wi-Fi?
  7. Why does my Wi-Fi disconnect frequently?
  8. How can I access the PM10 measurements from my Node/Pro?
  9. Connecting the Node/Pro to Wi-Fi networks with web authentication (captive portal)
  10. How can I update my Node/Pro’s software?
  11. How often does the Node/Pro's sensor take measurements? What is the difference between "Continuous" and "Default" mode?
  12. Why is my AirVisual Node/Pro showing higher pollution than outdoors?
  13. How can I see the PM2.5 concentation in µg/m3 on my AirVisual Node/Pro?
  14. My serial number does not exist
  15. How can I rename my AirVisual Node/Pro?
  16. How can I reset my AirVisual Node/Pro?
  17. What is pairing mode and how does it work?
  18. Can I use my AirVisual Node/Pro where there is no outdoor data?
  19. I want to register my AirVisual Node/Pro
  20. Node/Pro maintenance and sensor recalibration
  21. Payment options, shipping and warranty
  22. What's the difference between the Node/Pro's Enterprise and regular account?
  23. How can I get the most of my AirVisual Node/Pro's battery?
  24. Return Policy
  25. How do I display PM2.5 AQI and CO2 on the same screen?
  26. My Node/Pro shows a different measurement than the official outdoor station
  27. My Node/Pro shows 'No recent data' for Outdoor air quality
  28. Will my Node/Pro work without Wi-Fi?
  29. How do the PM2.5 sensor and CO2 sensor work?
  30. How does the AirVisual Node/Pro predict (forecast) future air quality?
  31. What temperature range can the AirVisual Node/Pro can function within?
  32. What is the size of the AirVisual Node/Pro's screen?
  33. What is included in the AirVisual Node/Pro box?
  34. What is the area coverage that the reading of Node/Pro is valid for?
  35. AirVisual Node/Pro Battery Information
  36. How can I view PM2.5 concentrations on the Node/Pro?
  37. Where can I find my Node/Pro’s serial number?
  38. What do each of the buttons on the Node/Pro do?
  39. AirVisual Node/Pro Dimensions & Weight
  40. Why does the AirVisual Node/Pro monitor PM2.5 and CO2?
  41. What is a "Share Code" and where can I find it?
  42. How do I view my Node/Pro’s data on the AirVisual website and app?
  43. Does the Pro/Node have an indoor & outdoor sensor?
  44. Will there be a VOC Pro/Node soon?
  45. Battery stays at 0% when charging and turns off when unplugged
  46. Cannot register my monitor's serial number
  47. How to change or unfollow an outdoor station on my Node/Pro?
  48. Node/Pro API returned JSON format
  49. Why is the Node/Pro's screen reading different to what is shown on the app?
  50. My PM2.5 sensor has got 'stuck' on a very high number
  51. Can the Pro's screen be switched off permanently, while still taking measurements?
  52. My device has stopped displaying outdoor data
  53. Samba data download troubleshooting

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